4 * ASSEMBLY SOURCE LISTING
8 * WITH COMPILER SECURITY
9 * AND VARIABLE LENGTH NAMES
11 * Adapted by Joel Matthew Rees
12 * from fig-FORTH for 6800 by Dave Lion, et. al.
14 * This free/libre/open source publication is provided
15 * through the courtesy of:
20 * and other interested parties.
23 * P.O. Box 8231 - San Jose, CA 95155 - (408) 277-0668
24 * URL: http://www.forth.org
25 * Further distribution must include this notice.
27 NAM Copyright: FORTH Interest Group, original authors, and Joel Matthew Rees
29 * filename fig-forth-auto6809opt.asm
30 * === FORTH-6809 {date} {time}
33 * Permission is hereby granted, free of charge, to any person obtaining a copy
34 * of this software and associated documentation files (the "Software"), to deal
35 * in the Software without restriction, including without limitation the rights
36 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
37 * copies of the Software, and to permit persons to whom the Software is
38 * furnished to do so, subject to the following conditions:
40 * The above copyright notice and this permission notice shall be included in
41 * all copies or substantial portions of the Software.
43 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
44 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
45 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
46 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
47 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
48 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
51 * "Associated documentation" for this declaration of license
52 * shall be interpreted to include only the comments in this file,
53 * or, if the code is split into multiple files,
54 * all files containing the complete source.
56 * This is the MIT model license, as published by the Open Source Consortium,
57 * with associated documentation defined.
58 * It was chosen to reflect the spirit of the original
59 * terms of use, which used archaic legal terminology.
62 * Authors of the 6800 model:
63 * === Primary: Dave Lion,
67 * === The Forth Interest Group
69 * === San Carlos, CA 94070
71 * === Unbounded Computing
72 * === 1134-K Aster Ave.
73 * === Sunnyvale, CA 94086
75 NATWID EQU 2 ; bytes per natural integer/pointer
76 * The original version was developed on an AMI EVK 300 PROTO
77 * system using an ACIA for the I/O.
78 * This version is developed targeting the Tandy Color Computer.
81 * is done in three subroutines:
82 * PEMIT ( word # 182 )
86 * The FORTH words for disc related I/O follow the model
87 * of the FORTH Interest Group, but have not yet been
88 * tested using a real disc.
90 * Addresses in the 6800 implementation reflect the fact that,
91 * on the development system, it was convenient to
92 * write-protect memory at hex 1000, and leave the first
93 * 4K bytes write-enabled. As a consequence, code from
94 * location $1000 to lable ZZZZ could be put in ROM.
95 * Minor deviations from the model were made in the
96 * initialization and words ?STACK and FORGET
97 * in order to do this.
98 * Those deviations will be altered in this
99 * implementation for the 6809 -- Color Computer.
102 * MEMORY MAP for this 16K|32K system:
103 * ( delineated so that systems with 4k byte write-
104 * protected segments can write protect FORTH )
106 * addr. contents pointer init by
107 * **** ******************************* ******* ******
110 * ACIAC EQU $FBCE the ACIA control address and
111 * ACIAD EQU ACIAC+1 data address for PROTO
113 MEMT32 EQU $7FFF ; Theoretical absolute end of all ram
114 MEMT16 EQU $3FFF ; 16K is too tight until we no longer need disc emulation.
121 * substitute for disc mass memory
122 RAMSCR EQU 8 ; addresses calculate as 2 (Too much for 16K in RAM only.)
125 MASSLO EQU MASSHI-RAMSCR*SCRSZ+1
130 * "end" of "usable ram" (If disc mass memory emulation is removed, actual end.)
135 USERSZ EQU 256 ; (Addressable by DP, must be 256 on even boundary)
136 USER16 EQU 1 ; We can change these for ROMPACK or 64K.
137 USER32 EQU 2 ; maybe?
139 USERLO EQU MEMEND-USERSZ*USERCT
142 * user tables of variables
143 * registers & pointers for the virtual machine
144 * scratch area for potential use in something, maybe?
148 * This is a really awkward place to define the disk buffer records.
150 * 4 buffer sectors of VIRTUAL MEMORY
151 NBLK EQU 4 ; # of disc buffer blocks for virtual memory
152 * Should NBLK be SCRSZ/SECTSZ?
153 * each block is SECTSZ+SECTRL bytes in size,
154 * holding SECTSZ characters
156 SECTRL EQU 2*NATWID ; Currently held sector number, etc.
157 BUFSZ EQU (SECTSZ+SECTRL)*NBLK
158 BUFBAS EQU USERLO-BUFSZ
159 * *BUG* SECTRL is hard-wired into several definitions.
160 * It will take a bit of work to ferret them out.
161 * It is too small, and it should not be hard-wired.
162 * SECTSZ was also hard-wired into several definitions,
163 * will I find them all?
169 * Don't want one return too many to destroy the disc buffers.
172 * 32D8|71D8 <== RP RINIT
174 IRP EQU BUFBAS-RPBUMP
176 RSTK16 EQU $50*NATWID ; 80 max levels nesting calls
177 RSTK32 EQU $90*NATWID ; 144 max
182 SFTBND EQU IRP-RSTKSZ ; (false boundary between TIB and return stack)
184 * holds up to TIBSZ characters
185 * and is scanned upward by IN
188 ITIB EQU SFTBND-TIBSZ
190 * 3148|6FB8 <== IN TIB
192 * Don't want terminal input and parameter underflow collisions
197 * 3140|6FB0 <== SP SP0,SINIT
199 * | grows downward from 3140|6FB0
204 * I DICTIONARY grows upward
206 * >>>>>>--------Two words to start RAMmable dictionary--------<<<<<<
209 * ???? end of ram-dictionary. <== DICTPT DPINIT
212 * ???? "FORTH" ( a word ) <=, <== CONTEXT
214 * start of ram-dictionary.
216 * >>>>>> memory from here up must be in RAM area <<<<<<
219 * 6k of romable "FORTH" <== IP ABORT
221 * the VIRTUAL FORTH MACHINE
223 * 1208 initialization tables
224 * 1204 <<< WARM START ENTRY >>>
225 * 1200 <<< COLD START ENTRY >>>
226 * 1200 lowest address used by FORTH
231 * >>>>>> memory from here down left alone <<<<<<
232 * >>>>>> so we can safely call ROM routines <<<<<<
238 * CONVENTIONS USED IN THIS PROGRAM ARE AS FOLLOWS :
240 * IP (hardware Y) points to the current instruction ( pre-increment mode )
241 * RP (hardware S) points to last return address pushedin return stack
242 * SP (hardware U) points to last byte pushed in data stack
244 * Y must be IP when NEXT is entered (if using the inner loop).
246 * When A and B hold one 16 bit FORTH data word,
247 * A contains the high byte, B, the low byte.
249 * UP (hardware DP) is the base of per-task ("user") variables.
250 * (Be careful of the stray semantics of "user".)
252 * W (hardware X) is the pointer to the "code field" address of native CPU
253 * machine code to be executed for the definition of the dictionary word
254 * to be executed/currently executing.
255 * The following natural integer (word) begins any "parameter section"
256 * (body) -- similar to a "this" pointer, but not the same.
257 * It may be native CPU machine code, or it may be a global variable,
258 * or it may be a list of Forth definition words (addresses).
261 * This implementation uses the native subroutine architecture
262 * rather than a postponed-push call that the 6800 model VM uses
263 * to save code and time in leaf routines.
265 * This should allow directly calling many of the Forth words
266 * from assembly language code.
267 * (Be aware of the need for a valid W in some cases.)
268 * It won't allow mixing assembly language directly into Forth word lists.
272 * 0 is false, anything else is true.
273 * Most places in this model that set a boolean flag set true as 1.
274 * This is in contrast to many models that set a boolean flag as -1.
279 * This system is shown with one user (task),
280 * but additional users (tasks) may be added
281 * by allocating additional user tables:
285 UBASEX RMB USERSZ data table for extra users
287 * Some of this stuff gets initialized during
288 * COLD start and WARM start:
289 * [ names correspond to FORTH words of similar (no X) name ]
293 * A few useful VM variables
294 * Will be removed when they are no longer needed.
295 * All are replaced by 6809 registers.
297 N RMB 10 used as scratch by (FIND),ENCLOSE,CMOVE,EMIT,KEY,
298 * SP@,SWAP,DOES>,COLD
301 * These locations are used by the TRACE routine :
303 TRLIM RMB 1 the count for tracing without user intervention
304 TRACEM RMB 1 non-zero = trace mode
305 BRKPT RMB 2 the breakpoint address at which
306 * the program will go into trace mode
307 VECT RMB 2 vector to machine code
308 * (only needed if the TRACE routine is resident)
311 * Registers used by the FORTH virtual machine:
315 W RMB 2 the instruction register points to 6800 code
316 * This is not exactly accurate. Points to the definiton body,
317 * which is native CPU machine code when it is native CPU machine code.
318 * IP RMB 2 the instruction pointer points to pointer to 6800 code
319 * RP RMB 2 the return stack pointer
320 * UP RMB 2 the pointer to base of current user's 'USER' table
321 * ( altered during multi-tasking )
323 *UORIG RMB 6 3 reserved variables
324 RMB 6 3 reserved variables
325 XSPZER RMB 2 initial top of data stack for this user
326 XRZERO RMB 2 initial top of return stack
327 XTIB RMB 2 start of terminal input buffer
328 XWIDTH RMB 2 name field width
329 XWARN RMB 2 warning message mode (0 = no disc)
330 XFENCE RMB 2 fence for FORGET
331 XDICTP RMB 2 dictionary pointer
332 XVOCL RMB 2 vocabulary linking
333 XBLK RMB 2 disc block being accessed
334 XIN RMB 2 scan pointer into the block
335 XOUT RMB 2 cursor position
336 XSCR RMB 2 disc screen being accessed ( O=terminal )
337 XOFSET RMB 2 disc sector offset for multi-disc
338 XCONT RMB 2 last word in primary search vocabulary
339 XCURR RMB 2 last word in extensible vocabulary
340 XSTATE RMB 2 flag for 'interpret' or 'compile' modes
341 XBASE RMB 2 number base for I/O numeric conversion
342 XDPL RMB 2 decimal point place
344 XCSP RMB 2 current stack position, for compile checks
347 XDELAY RMB 2 carriage return delay count
348 XCOLUM RMB 2 carriage width
349 IOSTAT RMB 2 last acia status from write/read
360 * end of user table, start of common system variables
369 * The FORTH program ( address $1200 to about $27FF ) will be written
370 * so that it can be in a ROM, or write-protected if desired,
371 * but right now we're just getting it running.
374 * ######>> screen 3 <<
376 ***************************
377 ** C O L D E N T R Y **
378 ***************************
382 ***************************
383 ** W A R M E N T R Y **
384 ***************************
386 * JMP WENT warm-start code, keeps current dictionary intact
387 LBSR WENT warm-start code, keeps current dictionary intact
391 ******* startup parmeters **************************
393 FDB $6809,0000 cpu & revision
394 FDB 0 topmost word in FORTH vocabulary
395 * BACKSP FDB $7F backspace character for editing
396 BACKSP FDB $08 backspace character for editing
397 UPINIT FDB UORIG initial user area
398 * UPINIT FDB UORIG initial user area
399 SINIT FDB ISP ; initial top of data stack
400 * SINIT FDB ORIG-$D0 initial top of data stack
401 RINIT FDB IRP ; initial top of return stack
402 * RINIT FDB ORIG-2 initial top of return stack
403 FDB ITIB ; terminal input buffer
404 * FDB ORIG-$D0 terminal input buffer
405 FDB 31 initial name field width
406 FDB 0 initial warning mode (0 = no disc)
407 FENCIN FDB REND initial fence
408 DPINIT FDB REND cold start value for DICTPT
409 BUFINT FDB BUFBAS Start of the disk buffers area
410 VOCINT FDB FORTH+4*NATWID
411 COLINT FDB TIBSZ initial terminal carriage width
412 DELINT FDB 4 initial carriage return delay
413 ****************************************************
417 * ######>> screen 13 <<
418 * These were of questionable use anyway,
419 * kept here now to satisfy the assembler and show hints.
420 * They're too much trouble to use with native subroutine call anyway.
421 * PULABX PULS A ; 24 cycles until 'NEXT'
423 * PULABX PULU A,B ; ?? cycles until 'NEXT'
424 * STABX STA 0,X 16 cycles until 'NEXT'
426 * STABX STD 0,X ; ?? cycles until 'NEXT'
428 * GETX LDA 0,X 18 cycles until 'NEXT'
430 * GETX LDD 0,X ?? cycles until 'NEXT'
431 * PUSHBA PSHS B ; 8 cycles until 'NEXT'
433 * PUSHBA PSHU A,B ; ?? cycles until 'NEXT'
437 * "NEXT" takes ?? cycles if TRACE is removed,
439 * and ?? cycles if trace is present and NOT tracing.
441 * = = = = = = = t h e v i r t u a l m a c h i n e = = = = =
443 * NEXT itself might just completely go away.
444 * About the only reason to keep it is to allowing executing a list
445 * which allows a cheap TRACE routine.
447 * NEXT is a loop which implements the Forth VM.
448 * It basically cycles through calling the code out of code lists,
450 * Using a native CPU return for this uses a few extra cycles per call,
451 * compared to simply jumping to each definition and jumping back
452 * to the known beginning of the loop,
453 * but the loop itself is really only there for convenience.
455 * This implementation uses the native subroutine call,
456 * to break the wall between Forth code and non-Forth code.
459 * LEAX 1,X ; pre-increment mode
462 NEXT ; IP is Y, push before using, pull before you come back here.
464 * NEXT2 LDX 0,X get W which points to CFA of word to be done
465 NEXT2 LDX ,Y++ get W which points to CFA of word to be done
468 * But NEXT2 is too much trouble to use with subroutine threading anyway.
470 NEXT3 ; W is X until you use X for something else. (TOS points back here.)
471 * But NEXT3 is too much trouble to use with subroutine threading anyway.
472 * LDX 0,X get VECT which points to executable code
474 * The next instruction could be patched to JMP TRACE =
475 * if a TRACE routine is available: =
479 JSR [,X] ; Saving the postinc cycles,
480 * ; but X must be bumped NATWID to the parameters.
482 * JMP TRACE ( an alternate for the above )
483 * BSR DBGREG ( an alternate for the above )
484 * In other words, with the call and the NOP,
485 * there is room to patch the call with a JMP to your TRACE
486 * routine, which you have to provide.
508 DBGNrt PULS CC,D,X,Y,PC
519 ADDB #$C7 ; ($40-$39)-$40
536 DBGREG PSHS U,Y,X,DP,B,A,CC
551 LDD 3*NATWID+4,S ; PC:505
558 LDD 2*NATWID+4,S ; U:50E
562 LDD 1*NATWID+4,S ; Y:513
564 LDD 0*NATWID+4,S ; X at 517
576 LDD [3*NATWID+4,S] ; PC
582 LDD [2*NATWID+4,S] ; U
586 LDD [1*NATWID+4,S] ; Y
588 LDD [0*NATWID+4,S] ; X
633 DBGRdU LDY 2*NATWID+4,S
641 DBGRrt PULS CC,A,B,DP,X,Y,U,PC
642 DBGRLB FCC 'DPCC PC S U Y X A B '
648 * = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = =
655 * Pushes the following natural width integer from the instruction stream
656 * as a literal, or immediate value.
661 * FDB LITERAL-TO-BE-PUSHED
664 * In native processor code, there should be a better way, use that instead.
665 * More specifically, DO NOT CALL THIS from assembly language code.
666 * (Note that there is no compile-only flag in the fig model.)
668 * See (FIND), or PFIND , for layout of the header format.
671 FCC 'LI' ; 'LIT' : NOTE: this is different from LITERAL
672 FCB $D4 ; 'T'|'\x80' ; character code for T, with high bit set.
673 FDB 0 ; link of zero to terminate dictionary scan
674 LIT FDB *+NATWID ; Note also that LIT is meaningless in native code.
686 * ######>> screen 14 <<
689 * Pushes the following byte from the instruction stream
690 * as a literal, or immediate value.
695 * FCB LITERAL-TO-BE-PUSHED
698 * If this is kept, it should have a header for TRACE to read.
699 * If the data bus is wider than a byte, you don't want to do this.
700 * Byte shaving like this is often counter-productive anyway.
701 * Changing the name to LIT8, hoping that will be more understandable.
702 * Also, see comments for LIT.
703 * (Note that there is no compile-only flag in the fig model.)
705 FCC 'LIT' ; 'LIT8' : NOTE: this is different from LITERAL
708 LIT8 FDB *+NATWID (this was an invisible word, with no header)
709 LDB ,Y+ ; This also is meaningless in native code.
721 * off is offset in video buffer area.
723 FCC 'SHOWTO' ; 'SHOWTOS'
752 * Jump to address on stack. Used by the "outer" interpreter to
753 * interactively invoke routines.
754 * Might be useful to have EXECUTE test the pointer, as done in BIF-6809.
756 FCC 'EXECUT' ; 'EXECUTE'
760 PULU X ; Gotta have W anyway, just in case.
761 JMP [,X] ; Tail return.
763 * LDX 0,X get code field address (CFA)
764 * LEAS 1,S ; pop stack
768 * ######>> screen 15 <<
771 * Add the following word from the instruction stream to the
772 * instruction pointer (Y++). Causes a program branch in Forth code stream.
774 * In native processor code, there should be a better way, use that instead.
775 * More specifically, DO NOT CALL THIS from assembly language code.
776 * This is only for Forth code stream.
777 * Also, see comments for LIT.
779 FCC 'BRANC' ; 'BRANCH'
782 BRAN FDB ZBYES ; Go steal code in ZBRANCH
784 * Moving code around to optimize the branch taking case in 0BRANCH.
785 ZBNO LEAY NATWID,Y ; No branch.
789 * BRANCH if flag is zero.
791 * In native processor code, there should be a better way, use that instead.
792 * More specifically, DO NOT CALL THIS from assembly language code.
793 * This is only for Forth code stream.
794 * Also, see comments for LIT.
796 FCC '0BRANC' ; '0BRANCH'
803 LEAY D,Y ; IP is postinc
807 * PSHS B ; ** emulating ABA:
811 * ZBYES LDX IP Note: code is shared with BRANCH, (+LOOP), (LOOP)
819 * ZBNO LDX IP no branch. This code is shared with (+LOOP), (LOOP).
820 * LEAX 1,X ; jump over branch delta
825 * ######>> screen 16 <<
827 * ( --- ) ( limit index *** limit index+1) C
828 * ( limit index *** )
829 * Counting loop primitive. The counter and limit are the top two
830 * words on the return stack. If the updated index/counter does
831 * not exceed the limit, a branch occurs. If it does, the branch
832 * does not occur, and the index and limit are dropped from the
835 * In native processor code, there should be a better way, use that instead.
836 * More specifically, DO NOT CALL THIS from assembly language code.
837 * This is only for Forth code stream.
838 * Also, see comments for LIT.
840 FCC '(LOOP' ; '(LOOP)'
844 LDD #1 ; Borrowing from BIF-6809.
845 XLOOPA ADDD NATWID,S ; Dodge the return address.
850 LDX ,S ; synthetic return
851 LEAS 3*NATWID,S ; Clean up the index and limit.
854 * LDB #1 get set to increment counter by 1 (Clears N.)
855 * BRA XPLOP2 go steal other guy's code!
858 * ( n --- ) ( limit index *** limit index+n ) C
859 * ( limit index *** )
860 * Loop with a variable increment. Terminates when the index
861 * crosses the boundary from one below the limit to the limit. A
862 * positive n will cause termination if the result index equals the
863 * limit. A negative n must cause the index to become less than
864 * the limit to cause loop termination.
866 * Note that the end conditions are not symmetric around zero.
868 * In native processor code, there should be a better way, use that instead.
869 * More specifically, DO NOT CALL THIS from assembly language code.
870 * This is only for Forth code stream.
871 * Also, see comments for LIT.
873 FCC '(+LOOP' ; '(+LOOP)'
876 XPLOOP FDB *+NATWID ; Borrowing from BIF-6809.
878 BPL XLOOPA ; Steal plain loop code for forward count.
879 ADDD NATWID,S ; Dodge the return address
883 BRA XLOOPN ; This path is less time-sensitive.
885 * This should work, but I want to use tested code.
886 * PULU A,B ; Get the increment.
887 * XPLOP2 PULS X ; Pre-clear the return stack.
888 * PSHU A ; Save the direction in high bit.
891 * SUBD NATWID,S ; Check limit.
893 ** I think this should work:
894 * EORA ,U+ ; dir < 0 and (count - limit) >= 0
895 * BPL XPLONO ; or dir >= 0 and (count - limit) < 0
897 * LEAY D,Y ; IP is postinc
899 * XPLONO LEAS 2*NATWID,S
900 * JMP ,X ; synthetic return
902 * This definitely should work:
903 * TST ,U+ ; Get the sign
908 * LEAY D,Y ; IP is postinc
910 * XPLOF CMPD NATWID,S
912 * XPLONO LEAS 2*NATWID,S
913 * JMP ,X ; synthetic return
915 * 6800 Probably could have used the exclusive-or method, too.:
916 * PULS A ; get increment
919 * BPL XPLOF forward looping
925 * BRA XPLONO fall through
929 * ADDB 3,X add it to counter
931 * STB 3,X store new counter value
940 * XPLONO LEAX 1,X ; done, don't branch back
945 * BRA ZBNO use ZBRAN to skip over unused delta
947 * ######>> screen 17 <<
949 * ( limit index --- ) ( *** limit index )
950 * Move the loop parameters to the return stack. Synonym for D>R.
955 XDO FDB *+NATWID This is the RUNTIME DO, not the COMPILING DO
956 LDX ,S ; Save the return address.
959 PULU A,B ; Maintain order.
961 JMP ,X ; synthetic return
980 * ( --- index ) ( limit index *** limit index )
981 * Copy the loop index from the return stack. Synonym for R.
986 LDD NATWID,S ; Dodge return address.
994 * ######>> screen 18 <<
996 * ( c base --- false )
997 * ( c base --- n true )
998 * Translate C in base, yielding a translation valid flag. If the
999 * translation is not valid in the specified base, only the false
1002 FCC 'DIGI' ; 'DIGIT'
1005 DIGIT FDB *+NATWID NOTE: legal input range is 0-9, A-Z
1006 LDD NATWID,U ; Check the whole thing.
1007 SUBD #$30 ; ascii zero
1008 BMI DIGIT2 IF LESS THAN '0', ILLEGAL
1010 BMI DIGIT0 IF '9' OR LESS
1012 BMI DIGIT2 if less than 'A'
1014 BPL DIGIT2 if greater than 'Z'
1015 SUBD #7 translate 'A' thru 'F'
1016 DIGIT0 CMPD ,U ; Check the base.
1017 BPL DIGIT2 if not less than the base
1018 STD NATWID,U ; Store converted digit. (High byte known zero.)
1019 LDD #1 ; set valid flag
1020 DIGIT1 STD ,U ; store the flag
1022 DIGIT2 LDD #0 ; set not valid flag
1023 LEAU NATWID,U ; pop base
1027 * SUBA #$30 ascii zero
1028 * BMI DIGIT2 IF LESS THAN '0', ILLEGAL
1030 * BMI DIGIT0 IF '9' OR LESS
1032 * BMI DIGIT2 if less than 'A'
1034 * BPL DIGIT2 if greater than 'Z'
1035 * SUBA #7 translate 'A' thru 'F'
1037 * BPL DIGIT2 if not less than the base
1039 * STA 3,X store digit
1040 * DIGIT1 STB 1,X store the flag
1044 * LEAS 1,S ; pop bottom number
1046 * STB 0,X make sure both bytes are 00
1049 * ######>> screen 19 <<
1051 * The word definition format in the dictionary:
1053 * (Symbol names are bracketed by bytes with the high bit set, rather than linked.)
1055 * NFA (name field address):
1056 * char-count + $80 Length of symbol name, flagged with high bit set.
1057 * char 1 Characters of symbol name.
1060 * char n + $80 symbol termination flag (char set < 128 code points)
1061 * LFA (link field address):
1062 * link high byte \___pointer to previous word in list
1063 * link low byte / -- Combined allocation/dictionary list. --
1064 * CFA (code field address):
1065 * CFA high byte \___pointer to native CPU machine code
1066 * CFA low byte / -- Consider this the characteristic code. --
1067 * PFA (parameter field address):
1068 * parameter fields -- Machine code for low-level native machine CPU code,
1069 * " instruction list for high-level Forth code,
1070 * " constant data for constants, pointers to per task variables,
1071 * " space for variables, for global variables, etc.
1073 * In the case of native CPU machine code, the address at CFA will be PFA.
1075 * Definition attributes:
1076 FIMMED EQU $40 ; Immediate word flag.
1077 FSMUDG EQU $20 ; Smudged => definition not ready.
1078 CTMASK EQU ($FF&(^($80|FIMMED))) ; For unmasking the length byte.
1079 * Note that the SMUDGE bit is not masked out.
1081 * But we really want more (Thinking for a new model, need one more byte):
1082 * FCOMPI EQU $10 ; Compile-time-only.
1083 * FASSEM EQU $08 ; Assembly-language code only.
1084 * F4THLV EQU $04 ; Must not be called from assembly language code.
1085 * These would require some significant adjustments to the model.
1086 * We also want to put the low-level VM stuff in its own vocabulary.
1089 * (FIND) ( name vocptr --- locptr length true )
1090 * ( name vocptr --- false )
1091 * Search vocabulary for a symbol called name.
1092 * name is a pointer to a high-bit bracket string with length head.
1093 * vocptr is a pointer to the NFA of the tail-end (LATEST) definition
1094 * in the vocabulary to be searched.
1095 * Hidden (SMUDGEd) definitions are lexically not equal to their name strings.
1097 FCC '(FIND' ; '(FIND)'
1101 PSHS Y ; Have to track two pointers.
1102 * Use the stack and registers instead of temp area N.
1103 PA0 EQU NATWID ; pointer to the length byte of name being searched against
1104 PD EQU 0 ; pointer to NFA of dict word being checked
1108 LDX PD,U ; Start in on the vocabulary (NFA).
1109 PFNDLP LDY PA0,U ; Point to the name to check against.
1110 LDB ,X+ ; get dict name length byte
1111 TFR B,A ; Save it in case it matches.
1114 CMPB ,Y+ ; Compare lengths
1118 TSTB ; ; Is high bit of character in dictionary entry set?
1122 ANDB #$7F ; Clear high bit from dictionary.
1123 CMPB ,Y+ ; Compare "last" characters.
1125 BEQ FOUND ; Matches even if dictionary actual length is shorter.
1126 PFNDLN LDX ,X++ ; Get previous link in vocabulary.
1128 BNE PFNDLP ; Continue if link not=0
1131 LEAU NATWID,U ; Return only false flag.
1138 PFNDCH CMPB ,Y+ ; Compare characters.
1142 PFNDSC LDB ,X+ ; scan forward to end of this name in dictionary
1150 FOUND LEAX 2*NATWID,X
1164 * NOP ; Probably leftovers from a debugging session.
1166 * PD EQU N ptr to dict word being checked
1172 * PFIND0 PULS A ; loop to get arguments
1179 * PFNDLP LDB 0,X get count dict count
1185 * LDA 0,X get count from arg
1187 * STX PA intialize PA
1188 * PSHS B ; ** emulating CBA:
1189 * CMPA ,S+ ; compare lengths
1199 * TSTB ; is dict entry neg. ?
1201 * ANDB #$7F clear sign
1202 * PSHS B ; ** emulating CBA:
1205 * PFNDLN LDX 0,X get new link
1206 * BNE PFNDLP continue if link not=0
1213 * PFNDCH PSHS B ; ** emulating CBA:
1217 * PFNDSC LDB 0,X scan forward to end of this name
1224 * FOUND LDA PD compute CFA
1237 * PSHS A ; Left over from a stray copy-paste, I guess.
1243 * ######>> screen 20 <<
1245 * ( buffer ch --- buffer symboloffset delimiteroffset scancount )
1246 * ( buffer ch --- buffer symboloffset nuloffset scancount ) ( Scan count == nuloffset )
1247 * ( buffer ch --- buffer nuloffset onepast scancount )
1248 * Scan buffer for a symbol delimited by ch or ASCII NUL,
1249 * return the length of the buffer region scanned,
1250 * the offset to the trailing delimiter,
1251 * and the offset of the first character of the symbol.
1252 * Leave the buffer on the stack.
1253 * Scancount is also offset to first character not yet looked at.
1254 * If no symbol in buffer, scancount and symboloffset point to NUL
1255 * and delimiteroffset points one beyond for some reason.
1256 * On trailing NUL, delimiteroffset == scancount.
1257 * (Buffer is the address of the buffer array to scan.)
1258 * (This is a bit too tricky, really.)
1260 FCC 'ENCLOS' ; 'ENCLOSE'
1264 LDA 1,U ; Delimiter character to match against in A.
1265 LDX NATWID,U ; Buffer to scan in.
1266 CLRB ; Initialize offset. (Buffer < 256 wide!)
1267 * Scan to a non-delimiter or a NUL
1268 ENCDEL TST B,X ; NUL ?
1270 CMPA B,X ; Delimiter?
1272 INCB ; count character
1274 * Found first character. Save the offset.
1275 ENC1ST STB 1,U ; Found first non-delimiter character --
1276 CLR ,U ; store the count, zero high byte.
1277 * Scan to a delimiter or a NUL
1278 ENCSYM TST B,X ; NUL ?
1280 CMPA B,X ; delimiter?
1284 * Found end of symbol. Push offset to delimiter found.
1285 ENCEND CLRA ; high byte -- buffer < 255 wide!
1286 PSHU A,B ; Offset to seen delimiter.
1287 * Advance and push address of next character to check.
1288 ADDD #1 ; In case offset was 255.
1291 * Found NUL before non-delimiter, therefore there is no word
1292 ENCNUL CLRA ; high byte -- buffer < 255 wide!
1293 STD ,U ; offset to NUL.
1294 ADDD #1 ; Point after NUL to allow (FIND) to match it.
1296 SUBD #1 ; Next is not passed NUL.
1297 PSHU A,B ; Stealing code will save only one byte.
1299 * Found NUL following the word instead of delimiter.
1304 PSHU A,B ; Save offset to first after symbol (NUL)
1306 PSHU A,B ; and count scanned.
1311 * FC means offset (bytes) to First Character of next word
1312 * EW " " to End of Word
1313 * NC " " to Next Character to start next enclose at
1314 * ENCLOS FDB *+NATWID
1316 * PULS B ; now, get the low byte, for an 8-bit delimiter
1320 * * wait for a non-delimiter or a NUL
1323 * PSHS B ; ** emulating CBA:
1324 * CMPA ,S+ ; CHECK FOR DELIM
1329 * * found first character. Push FC
1330 * ENC1ST LDA N found first char.
1334 * wait for a delimiter or a NUL
1337 * PSHS B ; ** emulating CBA:
1338 * CMPA ,S+ ; ckech for delim.
1343 * * found EW. Push it
1348 * * advance and push NC
1351 * found NUL before non-delimiter, therefore there is no word
1352 * ENCNUL LDB N found NUL
1356 * BRA ENC0TR+2 ; ********** POTENTIAL BUG HERE *******
1357 * ******** Should use labels in case opcodes change! ********
1358 * found NUL following the word instead of SPACE
1362 * ENCL8 LDB N save NC
1367 * ######>> screen 21 <<
1368 * The next 4 words call system dependant I/O routines
1369 * which are listed after word "-->" ( lable: "arrow" )
1370 * in the dictionary.
1374 * Write c to the output device (screen or printer).
1375 * ROM Uses the ECB device number at address $6F,
1376 * -2 is printer, 0 is screen.
1383 LBSR PEMIT ; PEMIT expects the character in D.
1392 * INC XOUT+1-UORIG,X
1394 * ****WARNING**** HARD OFFSET: *+4 ****
1401 * Wait for a key from the keyboard.
1402 * If the key is BREAK, set the high byte (result $FF03).
1408 LBSR PKEY ; PKEY leaves the key/break code in D.
1419 * Scan keyboard, but do not wait.
1420 * Return 0 if no key,
1421 * BREAK ($ff03) if BREAK is pressed,
1422 * or key currently pressed.
1424 FCC '?TERMINA' ; '?TERMINAL'
1428 LBSR PQTER ; PQTER leaves the flag/key in D.
1433 * JMP PUSHBA stack the flag
1437 * EMIT a Carriage Return (ASCII CR).
1443 LBRA PCR ; Nothing really to do here.
1447 * ######>> screen 22 <<
1449 * ( source target count --- )
1450 * Copy/move count bytes from source to target.
1451 * Moves ascending addresses,
1452 * so that overlapping only works if the source is above the destination.
1454 FCC 'CMOV' ; 'CMOVE' : source, destination, count
1458 * Another way ; takes ( 42+17*count+9*(count/256) cycles )
1460 SUBD ,U++ ; #2~9 ; invert the count
1471 CMOVEX PULS A,Y,PC ; #2~10
1491 * One way: ; takes ( 37+17*count+9*(count/256) cycles )
1492 * PSHS Y ; #2~7 ; Gotta have our pointers.
1495 * PULU D,X,Y ; #2~11
1496 * PSHS A ; #2~6 ; Gotta have our pointers.
1507 * BPL CMOVLP ; #2~3 ; If this actually works, it is limited to 32k here.
1509 * PULS A,Y,PC ; #2~10
1510 * Yet another way ; takes ( 37+29*count cycles )
1512 * LDX NATWID,U ; #2~6
1513 * LDY NATWID,U ; #3~7
1523 * LEAU 3*NATWID,U ; #2~5
1525 * Yet another way ; takes ( 44+24*odd+33*count/2 cycles )
1527 * LDX NATWID,U ; #2~6
1528 * LDY 2*NATWID,U ; #3~7
1546 * LEAU 3*NATWID,U ; #2~5
1548 * From the 6800 model:
1549 * CMOVE FDB *+2 takes ( 43+47*count cycles ) on 6800
1553 * STA 0,X move parameters to scratch area
1575 * ######>> screen 23 <<
1578 * Multiplies the top two unsigned integers,
1579 * yielding a double integer product.
1586 LDA 2*NATWID+1,U ; least
1590 LDA 2*NATWID,U ; most
1594 LDD 2*NATWID+1,U ; first inner (u2 lo, u1 hi)
1600 LDA 2*NATWID,U ; second inner (u2 hi)
1601 LDB 3*NATWID,U ; (u1 lo)
1618 * The following is a subroutine which
1619 * multiplies top 2 words on stack,
1620 * leaving 32-bit result: high order word in A,B
1621 * low order word in 2nd word of stack.
1623 * USTARS LDA #16 bits/word counter
1628 * USTAR2 ROR 5,X shift multiplier
1636 * RORB ; shift result
1638 * USTAR4 LEAS 1,S ; dump counter
1641 * ######>> screen 24 <<
1643 * ( ud u --- uremainder uquotient )
1644 * Divides the top unsigned integer
1645 * into the second and third words on the stack
1646 * as a single unsigned double integer,
1647 * leaving the remainder and quotient (quotient on top)
1648 * as unsigned integers.
1650 * The smaller the divisor, the more likely dropping the high word
1651 * of the quotient loses significant bits. See M/MOD .
1660 LDD NATWID,U ; dividend
1661 USLDIV CMPD ,U ; divisor
1663 ANDCC #~1 ; carry clear
1666 ORCC #1 ; quotient, (carry set)
1667 USLBIT ROL 2*NATWID+1,U ; save it
1679 PULS A,PC ; Avoiding a LEAS 1,S by discarding A.
1692 * USL2 ANDCC #~$01 ; CLC :
1710 * JMP SWAP+4 reverse quotient & remainder
1712 * ######>> screen 25 <<
1715 * Bitwise and the top two integers.
1735 * Bitwise or the top two integers.
1755 * Bitwise exclusive or the top two integers.
1773 * ######>> screen 26 <<
1776 * Fetch the parameter stack pointer (before it is pushed).
1777 * This points at whatever was on the top of stack before.
1787 * STX N scratch area
1792 * ( whatever --- nothing )
1793 * Initialize the parameter stack pointer from the USER variable S0.
1794 * Effectively clears the stack.
1803 * LDX XSPZER-UORIG,X
1804 * TFR X,S ; TXS : watch it ! X and S are not equal on 6800.
1807 * ( whatever *** nothing )
1808 * Initialize the return stack pointer from the initialization table
1809 * instead of the user variable R0, for some reason.
1810 * Quite possibly, this should be from R0.
1811 * Effectively aborts all in process definitions, except the active one.
1812 * An emergency measure, to be sure.
1813 * The routine that calls this must never execute a return.
1814 * So this should never be executed from the terminal, I guess.
1815 * This is another that should be compile-time only, and in a separate vocabulary.
1821 PULS X ; But this guy has to return to his caller.
1824 * LDX RINIT initialize from rom constant
1830 * Pop IP from return stack (return from high-level definition).
1831 * Can be used in a screen to force interpretion to terminate.
1832 * Must not be executed when temporaries are saved on top of the return stack.
1838 PULS D,Y ; return address in D, and saved IP in Y.
1839 TFR D,PC ; Synthetic return.
1846 * LDX 0,X get address we have just finished.
1847 * JMP NEXT+2 increment the return address & do next word
1849 * ######>> screen 27 <<
1851 * ( limit index *** index index )
1852 * Force the terminating condition for the innermost loop by
1853 * copying its index to its limit.
1854 * Termination is postponed until the next
1855 * LOOP or +LOOP instruction is executed.
1856 * The index remains available for use until
1857 * the LOOP or +LOOP instruction is encountered.
1858 * Note that the assumption is that the current count is the correct count
1859 * to end at, rather than pushing the count to the final count.
1861 FCC 'LEAV' ; 'LEAVE'
1865 LDD NATWID,S ; Dodge the return address.
1878 * Move top of parameter stack to top of return stack.
1886 STD ,S ; Put it where the return address was.
1901 * Move top of return stack to top of parameter stack.
1921 * Copy the top of return stack to top of parameter stack.
1933 * ######>> screen 28 <<
1936 * Logically invert top of stack;
1937 * or flag true if top is zero, otherwise false.
1947 * Logically invert top of stack;
1948 * or flag true if top is zero, otherwise false.
1966 *ZEQU2 TFR S,X ; TSX :
1971 * Flag true if top is negative (MSbit set), otherwise false.
1984 * LDA #$80 check the sign bit
1993 * ######>> screen 29 <<
1995 * ( n1 n2 --- n1+n2 )
1996 * Add top two words.
2013 * ( d1 d2 --- d1+d2 )
2014 * Add top two double integers.
2030 * ANDCC #~$01 ; CLC :
2046 * Negate (two's complement) top of stack.
2048 FCC 'MINU' ; 'MINUS'
2057 * from 6800 model code:
2068 * Negate (two's complement) top two words on stack as a double integer.
2070 FCC 'DMINU' ; 'DMINUS'
2075 SUBD NATWID,U ; #2~7
2095 * ######>> screen 30 <<
2097 * ( n1 n2 --- n1 n2 n1 )
2098 * Push a copy of the second word on stack.
2114 * Discard the top word on stack.
2127 * ( n1 n2 --- n2 n1 )
2128 * Swap the top two words on stack.
2152 * Push a copy of the top word on stack.
2167 * ######>> screen 31 <<
2170 * Add the second word on stack to the word at the adr on top of stack.
2185 * PULS A ; get stack data
2187 * ADDB 1,X add & store low byte
2189 * ADCA 0,X add & store hi byte
2195 * Exclusive or byte at adr with low byte of top word.
2197 FCC 'TOGGL' ; 'TOGGLE'
2205 * Using the model code would be less likely to introduce bugs,
2206 * but that would sort-of defeat my purposes here.
2207 * Anyway, I can borrow from theoretically known good bif-6809 code
2208 * and it's fewer bytes and much faster code this way.
2210 * FDB DOCOL,OVER,CAT,XOR,SWAP,CSTORE
2213 * ######>> screen 32 <<
2216 * Replace address on stack with the word at the address.
2225 * LDX 0,X get address
2232 * Replace address on top of stack with the byte at the address.
2233 * High byte of result is clear.
2255 * Store second word on stack at address on top of stack.
2265 * LDX 0,X get address
2272 * Store low byte of second word on stack at address on top of stack.
2273 * High byte is ignored.
2284 * LDX 0,X get address
2293 * ######>> screen 33 <<
2296 * { : name sundry-activities ; } typical input
2297 * If executing (not compiling),
2298 * record the data stack mark in CSP,
2299 * Set the CONTEXT vocabulary to CURRENT,
2301 * set state to compile,
2302 * and compile the call to the trailing native CPU machine code DOCOL.
2304 * This would not be hard to flatten to native code.
2305 * But that's not the purpose of a model.
2309 COLON FDB DOCOL,QEXEC,SCSP,CURENT,AT,CONTXT,STORE
2313 * Here is the IP pusher for allowing
2314 * nested words in the virtual machine:
2315 * ( ;S is the equivalent un-nester )
2318 * Characteristic of a colon (:) definition.
2319 * Begins execution of a high-level definition,
2320 * i. e., nests the definition and begins processing icodes.
2321 * Mechanically, it pushes the IP (Y register)
2322 * and loads the Parameter Field Address of the definition which
2323 * called it into the IP.
2324 DOCOL LDD ,S ; Save the return address.
2325 STY ,S ; Nest the old IP.
2326 LEAY NATWID,X ; W still in X, bump to parameters, load as new IP.
2327 TFR D,PC ; synthetic return to interpret.
2329 * DOCOL LDX RP make room in the stack
2335 * STA 2,X Store address of the high level word
2336 * STB 3,X that we are starting to execute
2337 * LDX W Get first sub-word of that definition
2338 * JMP NEXT+2 and execute it
2342 * { : name sundry-activities ; } typical input
2343 * ERROR check data stack against mark in CSP,
2345 * unSMUDGE LATEST definition,
2346 * and set state to interpretation.
2347 FCB $C1 ; imnediate code
2350 SEMI FDB DOCOL,QCSP,COMPIL,SEMIS,SMUDGE,LBRAK
2353 * ######>> screen 34 <<
2356 * { value CONSTANT name } typical input
2359 * compile the constant value,
2360 * and compile the call to the trailing native CPU machine code DOCON.
2362 FCC 'CONSTAN' ; 'CONSTANT'
2365 CON FDB DOCOL,CREATE,SMUDGE,COMMA,PSCODE
2367 * Characteristic of a CONSTANT.
2368 * A CONSTANT simply loads its value from its parameter field
2369 * and pushes it on the stack.
2370 DOCON LDD NATWID,X ; Get the first natural width word of the parameter field.
2375 * LDB 3,X A & B now contain the constant
2378 * Not in model, needed for abstraction:
2380 * The byte width of objects on stack.
2382 FCC 'NATWI' ; 'NATWID'
2388 * Not in model, needed for abstraction:
2389 * Note that this is not defined as an INCREMENTER!
2390 * Coded to increment by the exact constant returned by NATWID
2391 * ( n --- n+NATWID )
2398 ADDD NATWCV,PCR ; Looking ahead, does not have to be PCRelative.
2401 * How this might have been done for 6800 model:
2402 * CLRA ; We know the natural width is less than 255, LOL.
2411 * { init VARIABLE name } typical input
2412 * Use CONSTANT to CREATE a header and compile the initial value, init,
2413 * then overwrite the characteristic to point to DOVAR.
2415 FCC 'VARIABL' ; 'VARIABLE'
2418 VAR FDB DOCOL,CON,PSCODE
2420 * Characteristic of a VARIABLE.
2421 * A VARIABLE pushes its PFA address on the stack.
2422 * The parameter field of a VARIABLE is the actual allocation of the variable,
2423 * so that pushing its address allows its contents to be @ed (fetched).
2424 * Ordinary arrays and strings that do not subscript themselves
2425 * may be allocated by defining a variable
2426 * and immediately ALLOTting the remaining needed space.
2427 * VARIABLES are global to all users,
2428 * and thus should be hidden in resource monitors, but aren't.
2429 DOVAR LEAX NATWID,X ; Point to the first natural width word of the parameters.
2435 * ADCA #0 A,B now contain the address of the variable
2440 * { uboffset USER name } typical input
2441 * CREATE a header and compile the unsigned byte offset in the per-USER table,
2442 * then overwrite the header with a call to DOUSER.
2443 * The USER is entirely responsible for maintaining allocation!
2448 USER FDB DOCOL,CON,PSCODE
2450 * Characteristic of a per-USER variable.
2451 * USER variables are similiar to VARIABLEs,
2452 * but are allocated (by hand!) in the per-user table.
2453 * A USER variable's parameter field contains its offset in the per-user table.
2454 DOUSER TFR DP,A ; Make a pointer to the direct page.
2456 * See Alternative -- alternatives start from this point.
2457 ADDD NATWID,X ; Add it to the offset to the per-user variable.
2459 TFR D,X ; Cache the pointer in X for the caller.
2461 * Hey, the per-user table could actually be larger than 256 bytes!
2462 * But we knew that. It's just not as esthetic to calculate it this way.
2464 * LDX NATWID,X ; Keep the offset
2465 * EXG D,X ; Prepare for EA
2470 * PSHS Y ; Get Y free for calculations.
2471 * TFR D,Y ; Y points to the UP base
2472 * LDD NATWID,X ; Get the offset
2473 * LEAX D,Y ; Leave the pointer cached in X.
2477 * From the 6800 model:
2478 * DOUSER LDX W get offset into user's table
2481 * ADDB UP+1 add to users base address
2483 * JMP PUSHBA push address of user's variable
2485 * ######>> screen 35 <<
2520 * ASCII SPACE character
2525 BL FDB DOCON ascii blank
2529 * This really shouldn't be a CONSTANT.
2531 * The base of the disk buffer space.
2533 FCC 'FIRS' ; 'FIRST'
2538 * FDB MEMEND-528 (132 * NBLK)
2541 * This really shouldn't be a CONSTANT.
2543 * The limit of the disk buffer space.
2545 FCC 'LIMI' ; 'LIMIT' : ( the end of memory +1 )
2550 * In 6800 model, was
2554 * ( --- sectorsize )
2555 * The size, in bytes, of a buffer control region.
2557 FCC 'B/CT' ; 'B/CTL' : (bytes/control region)
2563 * ( --- sectorsize )
2564 * The size, in bytes, of a buffer.
2566 FCC 'B/BU' ; 'B/BUF' : (bytes/buffer)
2571 * Hardcoded in 6800 model:
2575 * ( --- blocksperscreen )
2576 * The size, in blocks, of a screen.
2577 * Should this be the same as NBLK, the number of block buffers maintained?
2579 FCC 'B/SC' ; 'B/SCR' : (blocks/screen)
2584 * Hardcoded in 6800 model as:
2586 * blocks/screen = 1024 / "B/BUF" = 8, if sectors are 128 bytes.
2590 * Calculate the address of entry (#n/2) in the boot-up parameter table.
2591 * (Adds the base of the boot-up table to n.)
2593 FCC '+ORIGI' ; '+ORIGIN'
2596 PORIG FDB DOCOL,LIT,ORIG,PLUS
2599 * ######>> screen 36 <<
2602 * This is the per-task variable recording the initial parameter stack pointer.
2612 * This is the per-task variable recording the initial return stack pointer.
2622 * Terminal Input Buffer address.
2623 * Note that this is a variable, so users may allocate their own buffers, but it must be @ed.
2632 * ( --- maxnamewidth )
2633 * This is the maximum width to which symbol names will be recorded.
2635 FCC 'WIDT' ; 'WIDTH'
2643 * Availability of error messages on disk.
2644 * Contains 1 if messages available,
2646 * -1 if a disk error has occurred.
2648 FCC 'WARNIN' ; 'WARNING'
2656 * Boundary for FORGET.
2658 FCC 'FENC' ; 'FENCE'
2666 * Dictionary pointer, fetched by HERE.
2668 FCC 'D' ; 'DP' : points to first free byte at end of dictionary
2675 * ( --- vadr ) ******* Need to check what this is!
2676 * Used in maintaining vocabularies.
2677 * I think it points to the "parent" vocabulary, but I'm not sure.
2678 * Or maybe this is the CONTEXT vocabulary. I'll have to come back here. *****
2680 FCC 'VOC-LIN' ; 'VOC-LINK'
2688 * Disk block being interpreted.
2689 * Zero refers to terminal.
2690 * ******** Should be made a 32 bit user variable! ********
2691 * But the base system needs to have full 32 bit support, div and mul, etc.
2692 * before we can do that.
2702 * Input buffer offset/cursor.
2704 FCC 'I' ; 'IN' : scan pointer for input line buffer
2712 * Output buffer offset/cursor.
2722 * Screen currently being edited, once we have an editor running.
2729 * ######>> screen 37 <<
2733 * Sector offset for LOADing screens,
2734 * set by DRIVE to make a new drive the default.
2735 * This should also be 32 bit or bigger.
2737 FCC 'OFFSE' ; 'OFFSET'
2745 * Current context of interpretation (vocabulary root).
2747 FCC 'CONTEX' ; 'CONTEXT' : points to pointer to vocab to search first
2755 * Current context of definition (vocabulary root).
2757 FCC 'CURREN' ; 'CURRENT' : points to ptr. to vocab being extended
2765 * Compiler/interpreter state.
2767 FCC 'STAT' ; 'STATE' : 1 if compiling, 0 if not
2775 * Numeric conversion base.
2777 FCC 'BAS' ; 'BASE' : number base for all input & output
2785 * Decimal point location for output.
2795 * Field width for I/O formatting.
2805 * Compiler stack mark for stack check.
2815 * Editing cursor location.
2825 * Pointer to last HELD character in PAD.
2833 * ======>> 82.5 <<== SPECIAL
2835 * Line width of active terminal.
2837 FCC 'COLUMN' ; 'COLUMNS' : line width of terminal
2843 * ######>> screen 38 <<
2845 ** An INCREMENTER probably should not be defined without a defined CONSTANT?
2847 ** Make an INCREMENTER compiling word (not in model):
2849 ** { n INCREMENTER name } typical input
2850 ** CREATE a header and compile the increment constant,
2851 ** then overwrite the header with a call to DOINC.
2853 * FCC 'INCREMENTE' ; 'INCREMENTER'
2856 * INCR FDB DOCOL,CON,PSCODE
2858 ** Characteristic of an INCREMENTER.
2859 ** This is too naive:
2861 * ADDD NATWID,X ; Add the increment.
2864 * Compiling word should check that it is compiling a CONSTANT.
2872 * Using the model keeps things semantically connected for other processors:
2873 ONEP FDB DOCOL,ONE,PLUS
2875 ** Greedy alternative:
2881 * Naive alternative:
2884 * Naive alternative:
2887 * ADDD #1 ; It's hard to imagine 1+ being other than 1.
2897 * Using the model keeps things semantically connected for other processors:
2898 TWOP FDB DOCOL,TWO,PLUS
2900 ** Greedy alternative:
2903 * ADDD TWOV,PCR ; See NAT+ (NATP)
2906 * Naive alternative:
2909 * Naive alternative:
2912 * ADDD #2 ; See NAT+ (NATP)
2918 * Get the DICTPT allocation, like a USER constant.
2919 * Should check the stack and heap for collision.
2924 HERE FDB DOCOL,DICTPT,AT
2929 * Increase/decrease heap (add n to DP),
2930 * Should ERROR check stack/heap.
2932 FCC 'ALLO' ; 'ALLOT'
2935 ALLOT FDB DOCOL,DICTPT,PSTORE
2940 * Store word n at DP++,
2941 * Should ERROR check stack/heap.
2945 COMMA FDB DOCOL,HERE,STORE,NATWC,ALLOT
2947 * COMMA FDB DOCOL,HERE,STORE,TWO,ALLOT
2952 * Store byte b at DP+,
2953 * Should ERROR check stack/heap.
2958 CCOMM FDB DOCOL,HERE,CSTORE,ONE,ALLOT
2962 * ( n1 n2 --- n1-n2 )
2963 * Subtract top two words.
2972 * SUB FDB DOCOL,MINUS,PLUS
2973 * FDB SEMIS ; Costs 6 bytes and lots of cycles.
2976 * ( n1 n2 --- n1==n2 )
2977 * Return flag true if n1 and n2 are equal, otherwise false.
2981 EQUAL FDB DOCOL,SUB,ZEQU
2985 * ( n1 n2 --- n1<n2 )
2986 * Return flag true if n1 is less than n2, otherwise false.
3007 * CMPB 1,X ; Why not sub, sbc, bge?
3017 * ( n1 n2 --- n1>n2 )
3018 * Return flag true if n1 is greater than n2, false otherwise.
3022 GREAT FDB DOCOL,SWAP,LESS
3026 * ( n1 n2 n3 --- n2 n3 n1 )
3027 * Rotate the top three words on stack,
3028 * bringing the third word to the top.
3039 * ROT FDB DOCOL,TOR,SWAP,FROMR,SWAP
3046 FCC 'SPAC' ; 'SPACE'
3049 SPACE FDB DOCOL,BL,EMIT
3053 * ( n0 n1 --- min(n0,n1) )
3054 * Leave the minimum of the top two integers.
3055 * Being too greedy here, but, whatever.
3066 * MIN FDB DOCOL,OVER,OVER,GREAT,ZBRAN
3073 * ( n0 n1 --- max(n0,n1) )
3074 * Leave the maximum of the top two integers.
3075 * Really should leave this as in the model.
3086 * MAX FDB DOCOL,OVER,OVER,LESS,ZBRAN
3105 * DDUP FDB DOCOL,DUP,ZBRAN
3106 * FDB DDUP2-*-NATWID
3110 * ######>> screen 39 <<
3115 * Change top integer to its sign.
3117 FCC 'SIGNU' ; 'SIGNUM'
3125 SIGNUP SEX ; Couldn't they have called SignEXtend EXT instead?
3126 STD ,U ; Am I too much of a prude?
3128 * 6800 model version should be something like this:
3139 * ( adr1 direction --- adr2 )
3140 * TRAVERSE the symbol name.
3141 * If direction is 1, find the end.
3142 * If direction is -1, find the beginning.
3144 FCC 'TRAVERS' ; 'TRAVERSE'
3148 BSR SIGNUE ; Convert negative to -, zero or positive to 1.
3149 LDD ,U++ ; Still in D, but we have to pop it anyway.
3150 LDX ,U ; If D is 1 or -1, so is B.
3152 TRAVLP LEAX B,X ; Don't look at the one we start at.
3153 CMPA ,X ; Not sure why we aren't just doing LDA ,X ; BPL.
3157 * Doing this in 6809 just because it can be done may be getting too greedy.
3158 * TRAV FDB DOCOL,SWAP
3159 * TRAV2 FDB OVER,PLUS,LIT8
3161 * FDB OVER,CAT,LESS,ZBRAN
3162 * FDB TRAV2-*-NATWID
3168 * Fetch CURRENT as a per-USER constant.
3170 FCC 'LATES' ; 'LATEST'
3173 LATEST FDB DOCOL,CURENT,AT,AT
3175 * LATEST FDB *+NATWID
3176 * Getting too greedy:
3181 * LDD CURENT+NATWID,PCR
3183 * PSHU X ; Leave the address in X.
3192 * Too greedy, too many smantic holes to fall through.
3193 * If the address at the CFA is made relative,
3194 * this is part of the code that would be affected
3195 * if it is in native CPU code.
3198 * Wanted to do these as INCREMENTERs,
3199 * but I need to stick with the model as much as possible,
3200 * (mostly, LOL) adding code only to make the model more clear.
3202 * Convert PFA to LFA, unchecked. (Bump back from contents to allocation link.)
3215 * Convert PFA to CFA, unchecked. (Bump back from contents to characterist code link.)
3220 * CFA FDB DOCOL,TWO,SUB
3221 CFA FDB DOCOL,NATWC,SUB
3226 * Convert PFA to NFA. (Bump back from contents to beginning of symbol name.)
3234 FDB SUB,ONE,MINUS,TRAV
3239 * Convert NFA to PFA. (Bump up from beginning of symbol name to contents.)
3244 PFA FDB DOCOL,ONE,TRAV,LIT8
3250 * ######>> screen 40 <<
3253 * Save the parameter stack pointer in CSP for compiler checks.
3258 SCSP FDB DOCOL,SPAT,CSP,STORE
3262 * ( 0 n --- ) ( *** )
3263 * ( true n --- IN BLK ) ( anything *** nothing )
3264 * If flag is false, do nothing.
3265 * If flag is true, issue error MESSAGE and QUIT or ABORT, via ERROR.
3266 * Leaves cursor position (IN)
3267 * and currently loading block number (BLK) on stack, for analysis.
3269 * This one is too important to be high-level Forth codes.
3270 * When we have an error, we want to disturb as little as possible.
3271 * But fixing that cascades through ERROR and MESSAGE
3272 * into the disk block system.
3273 * And we aren't ready for that yet.
3275 FCC '?ERRO' ; '?ERROR'
3283 ** this doesn't work anyway: QERROR LBR ERROR
3284 QERR FDB DOCOL,SWAP,ZBRAN
3292 * STATE is compiling:
3294 * STATE is compiling:
3295 * ( --- IN BLK ) ( anything *** nothing )
3296 * ERROR if not compiling.
3298 FCC '?COM' ; '?COMP'
3301 QCOMP FDB DOCOL,STATE,AT,ZEQU,LIT8
3307 * STATE is executing:
3309 * STATE is executing:
3310 * ( --- IN BLK ) ( anything *** nothing )
3311 * ERROR if not executing.
3313 FCC '?EXE' ; '?EXEC'
3316 QEXEC FDB DOCOL,STATE,AT,LIT8
3322 * ( n1 n1 --- ) ( *** )
3323 * ( n1 n2 --- IN BLK ) ( anything *** nothing )
3324 * ERROR if top two are unequal.
3325 * MESSAGE says compiled conditionals do not match.
3327 FCC '?PAIR' ; '?PAIRS'
3330 QPAIRS FDB DOCOL,SUB,LIT8
3336 * CSP and parameter stack are balanced (equal):
3338 * CSP and parameter stack are not balanced (unequal):
3339 * ( --- IN BLK ) ( anything *** nothing )
3340 * ERROR if return/control stack is not at same level as last !CSP.
3341 * Usually indicates that a definition has been left incomplete.
3346 QCSP FDB DOCOL,SPAT,CSP,AT,SUB,LIT8
3354 * No active BLK input:
3355 * ( --- IN BLK ) ( anything *** nothing )
3356 * ERROR if not loading, i. e., if BLK is zero.
3358 FCC '?LOADIN' ; '?LOADING'
3361 QLOAD FDB DOCOL,BLK,AT,ZEQU,LIT8
3366 * ######>> screen 41 <<
3369 * Compile an in-line literal value from the instruction stream.
3371 FCC 'COMPIL' ; 'COMPILE'
3374 * COMPIL FDB DOCOL,QCOMP,FROMR,TWOP,DUP,TOR,AT,COMMA
3375 * COMPIL FDB DOCOL,QCOMP,FROMR,NATP,DUP,TOR,AT,COMMA
3376 COMPIL FDB DOCOL,QCOMP,FROMR,DUP,NATP,TOR,AT,COMMA
3381 * Clear the compile state bit(s) (shift to interpret).
3385 LBRAK FDB DOCOL,ZERO,STATE,STORE
3392 * Set the compile state bit(s) (shift to compile).
3396 RBRAK FDB DOCOL,LIT8
3403 * Toggle SMUDGE bit of LATEST definition header,
3404 * to hide it until defined or reveal it after definition.
3406 FCC 'SMUDG' ; 'SMUDGE'
3409 SMUDGE FDB DOCOL,LATEST,LIT8
3416 * Set the conversion base to sixteen (b00010000).
3423 FCB 16 ; decimal sixteen
3429 * Set the conversion base to ten (b00001010).
3431 FCC 'DECIMA' ; 'DECIMAL'
3436 FCB 10 ; decimal ten
3440 * ######>> screen 42 <<
3442 * ( --- ) ( IP *** )
3443 * Pop the saved IP and use it to
3444 * compile the latest symbol as a reference to a ;CODE definition;
3445 * overwrite the code field of the symbol found by LATEST
3446 * with the address of the low-level characteristic code
3447 * provided in the defining definition.
3448 * Look closely at where things return, consider the operation of R> and >R .
3450 * The machine-level code which follows (;CODE) in the instruction stream
3451 * is not executed by the defining symbol,
3452 * but becomes the characteristic of the defined symbol.
3453 * This is the usual way to generate the characteristics of VARIABLEs,
3454 * CONSTANTs, COLON definitions, etc., when FORTH compiles itself.
3456 * Finally, note that, if code shifts from low level back to high
3457 * (native CPU machine code calling into a list of FORTH codes),
3458 * the low level code can't just call a high-level definition.
3459 * Leaf definitions can directly call other leaf definitions,
3460 * but not non-leafs.
3461 * It will need an anonymous list, probably embedded in the low-level code,
3462 * and Y and X will have to be set appropriately before entering the list.
3464 FCC '(;CODE' ; '(;CODE)'
3467 * PSCODE FDB DOCOL,FROMR,TWOP,LATEST,PFA,CFA,STORE
3468 PSCODE FDB DOCOL,FROMR ; Y/IP is post-inc, needs no adjustment.
3469 FDB LATEST,PFA,CFA,STORE
3474 * ?CSP to see if there are loose ends in the defining definition
3475 * before shifting to the assembler,
3476 * compile (;CODE) in the defining definition's instruction stream,
3477 * shift to interpreting,
3478 * make the ASSEMBLER vocabulary current,
3479 * and !CSP to mark the stack
3480 * in preparation for assembling low-level code.
3481 * Note that ;CODE, unlike DOES>, is IMMEDIATE,
3482 * and compiles (;CODE),
3483 * which will do the actual work of changing
3484 * the LATEST definition's characteristic when the defining word runs.
3485 * Assembly is done by the interpreter, rather than the compiler.
3486 * I could have avoided the anomalous three-byte code fields by
3488 * Note that the ASSEMBLER is not part of the model (at this time).
3489 * That means that, until the assembler is ready,
3490 * if you want to define low-level words,
3491 * you have to poke (comma) in hand-assembled stuff.
3494 FCC ';COD' ; ';CODE'
3497 SEMIC FDB DOCOL,QCSP,COMPIL,PSCODE,SMUDGE,LBRAK,QSTACK
3499 * note: "QSTACK" will be replaced by "ASSEMBLER" later
3501 * ######>> screen 43 <<
3504 * Make the word currently being defined
3505 * build a header for DOES> definitions.
3506 * Actually just compiles a CONSTANT zero
3507 * which can be overwritten later by DOES>.
3508 * Since the fig models were established, this technique has been deprecated.
3510 * Note that <BUILDS is not IMMEDIATE,
3511 * and therefore executes during a definition's run-time,
3512 * rather than its compile-time.
3513 * It is not intended to be used directly,
3514 * but rather so that one definition word can build another.
3515 * Also, note that nothing particularly special happens
3516 * in the defining definition until DOES> executes.
3517 * The name <BUILDS is intended to be a reminder of what is about to occur.
3519 * <BUILDS probably should have compiled an ERROR instead of a ZERO CONSTANT.
3521 FCC '<BUILD' ; '<BUILDS'
3524 BUILDS FDB DOCOL,ZERO,CON
3528 * ( --- ) ( IP *** ) C
3529 * Define run-time behavior of definitions compiled/defined
3530 * by a high-level defining definition --
3531 * the FORTH equivalent of a compiler-compiler.
3532 * DOES> assumes that the LATEST symbol table entry
3533 * has at least one word of parameter field,
3534 * which <BUILDS provides.
3535 * Note that DOES> is also not IMMEDIATE.
3537 * When the defining word containing DOES> executes the DOES> icode,
3538 * it overwrites the LATEST symbol's CFA with jsr <XDOES,
3539 * overwrites the first word of that symbol's parameter field with its own IP,
3540 * and pops the previous IP from the return stack.
3541 * The icodes which follow DOES> in the stream
3542 * do not execute at the defining word's run-time.
3544 * Examining XDOES in the virtual machine shows
3545 * that the defined word will execute those icodes
3546 * which follow DOES> at its own run-time.
3548 * The advantage of this kind of behaviour,
3549 * which you will also note in ;CODE,
3550 * is that the defined word can contain
3551 * both operations and data to be operated on.
3552 * This is how FORTH data objects define their own behavior.
3554 * Finally, note that the effective parameter field for DOES> definitions
3555 * starts two NATWID words after the CFA, instead of just one
3556 * (four bytes instead of two in a sixteen-bit addressing Forth).
3558 * VOCABULARYs will use this. See definition of word FORTH.
3560 FCC 'DOES' ; 'DOES>'
3563 * DOES FDB DOCOL,FROMR,TWOP,LATEST,PFA,STORE
3564 DOES FDB DOCOL,FROMR ; Y/IP is post-inc, needs no adjustment.
3565 FDB LATEST,PFA,STORE
3568 * ( --- PFA+NATWID ) ( *** IP )
3569 * Characteristic of a DOES> defined word.
3570 * The characteristics of DOES> definitions are written in high-level
3571 * Forth codes rather than native CPU machine level code.
3572 * The first parameter word points to the high-level characteristic.
3573 * This routine's job is to push the IP,
3574 * load the high level characteristic pointer in IP,
3575 * and leave the address following the characteristic pointer on the stack
3576 * so the parameter field can be accessed.
3577 DODOES LDD ,S ; Keep the return address.
3578 STY ,S ; Save/nest the current IP on the return stack.
3579 LDY NATWID,X ; First parameter is new IP.
3580 LEAX 2*NATWID,X ; Address of second parameter.
3582 TFR D,PC ; Synthetic return.
3584 * From the 6800 model:
3587 * LDX RP make room on return stack
3591 * STA 2,X push return address
3593 * LDX W get addr of pointer to run-time code
3596 * STX N stash it in scratch area
3597 * LDX 0,X get new IP
3599 * CLRA ; get address of parameter
3603 * PSHS B ; and push it on data stack
3607 * ######>> screen 44 <<
3609 * ( strptr --- strptr+1 count )
3610 * Convert counted string to string and count.
3611 * (Fetch the byte at strptr, post-increment.)
3613 FCC 'COUN' ; 'COUNT'
3616 COUNT FDB DOCOL,DUP,ONEP,SWAP,CAT
3620 * ( strptr count --- )
3621 * EMIT count characters at strptr.
3626 TYPE FDB DOCOL,DDUP,ZBRAN
3628 FDB OVER,PLUS,SWAP,XDO
3629 TYPE2 FDB I,CAT,EMIT,XLOOP
3637 * ( strptr count1 --- strptr count2 )
3638 * Supress trailing blanks (subtract count of trailing blanks from strptr).
3640 FCC '-TRAILIN' ; '-TRAILING'
3643 DTRAIL FDB DOCOL,DUP,ZERO,XDO
3644 DTRAL2 FDB OVER,OVER,PLUS,ONE,SUB,CAT,BL
3656 * TYPE counted string out of instruction stream (updating IP).
3661 * PDOTQ FDB DOCOL,R,TWOP,COUNT,DUP,ONEP
3662 * PDOTQ FDB DOCOL,R,NATP,COUNT,DUP,ONEP
3663 PDOTQ FDB DOCOL,R,COUNT,DUP,ONEP
3664 FDB FROMR,PLUS,TOR,TYPE
3669 * { ." something-to-be-printed " } typical input
3670 * Use WORD to parse to trailing quote;
3671 * if compiling, compile XDOTQ and string parsed,
3672 * otherwise, TYPE string.
3682 FDB COMPIL,PDOTQ,WORD
3683 FDB HERE,CAT,ONEP,ALLOT,BRAN
3685 DOTQ1 FDB WORD,HERE,COUNT,TYPE
3688 * ######>> screen 45 <<
3689 * ======>> 126 <<== MACHINE DEPENDENT
3691 * ( --- IN BLK ) ( anything *** nothing )
3692 * ERROR if parameter stack out of bounds.
3694 * But checking whether the stack is in bounds or not
3695 * really should not use the stack.
3696 * And there really should be a ?RSTACK, as well.
3698 FCC '?STAC' ; '?STACK'
3701 QSTACK FDB DOCOL,LIT8
3704 * But why use that instead of XSPZER (S0)?
3705 * Multi-user or multi-tasking would not want that.
3707 * FDB PORIG,AT,TWO,SUB,SPAT,LESS,ONE
3708 FDB PORIG,AT,SPAT,LESS,ONE ; Not post-decrement push.
3710 * prints 'empty stack'
3713 * Here, we compare with a value at least 128
3714 * higher than dict. ptr. (DICTPT)
3716 FCB $80 ; This is a rough check anyway, leave it as is.
3719 FDB TWO ; NOT the NATWID constant!
3721 * prints 'full stack'
3725 * ======>> 127 << this word's function
3726 * is done by ?STACK in this version
3731 *QFREE FDB DOCOL,SPAT,HERE,LIT8
3733 * FDB PLUS,LESS,TWO,QERR,SEMIS ; This TWO is not NATWID!
3735 * ######>> screen 46 <<
3738 * ***** Check that this is how it works here:
3739 * Get up to n-1 characters from the keyboard,
3740 * storing at buffer and echoing, with backspace editing,
3741 * quitting when a CR is read.
3742 * Terminate it with a NUL.
3744 FCC 'EXPEC' ; 'EXPECT'
3747 EXPECT FDB DOCOL,OVER,PLUS,OVER,XDO ; brace the buffer area
3748 * EXPEC2 FDB KEY,DUP,LIT8
3750 * FDB LIT,$1C,SHOTOS ; DBG
3753 FDB PORIG,AT,EQUAL,ZBRAN ; check for backspacing
3756 FCB 8 ( backspace character to emit )
3757 FDB OVER,I,EQUAL,DUP,FROMR,TWO,SUB,PLUS ; back I up TWO characters
3761 FCB $D ( carriage return )
3764 FDB LEAVE,DROP,BL,ZERO,BRAN ; I think this is the NUL terminator.
3767 EXPEC5 FDB I,CSTORE,ZERO,I,ONEP,STORE
3768 EXPEC6 FDB EMIT,XLOOP
3775 * EXPECT 128 (TWID) characters to TIB.
3777 FCC 'QUER' ; 'QUERY'
3780 QUERY FDB DOCOL,TIB,AT,COLUMS
3781 FDB AT,EXPECT,ZERO,IN,STORE
3786 * End interpretation of a line or screen, and/or prepare for a new block.
3787 * Note that the name of this definition is an empty string,
3788 * so it matches on the terminating NUL in the terminal or block buffer.
3789 FCB $C1 immediate < carriage return >
3792 NULL FDB DOCOL,BLK,AT,ZBRAN
3795 FDB ZERO,IN,STORE,BLK,AT,BSCR,MOD
3797 * check for end of screen
3800 FDB QEXEC,FROMR,DROP
3803 NULL2 FDB FROMR,DROP
3806 * ######>> screen 47 <<
3809 * Fill n bytes at adr with b.
3810 * This relies on CMOVE having a certain lack of parameter checking,
3811 * where overlapping regions are not properly inverted in copy.
3812 * And this really should be done in low-level.
3813 * None of the advantages of doing things in high-level apply to fill.
3818 FILL FDB DOCOL,SWAP,TOR,OVER,CSTORE,DUP,ONEP
3819 FDB FROMR,ONE,SUB,CMOVE
3824 * Fill n bytes with 0.
3826 FCC 'ERAS' ; 'ERASE'
3829 ERASE FDB DOCOL,ZERO,FILL
3834 * Fill n bytes with ASCII SPACE.
3836 FCC 'BLANK' ; 'BLANKS'
3839 BLANKS FDB DOCOL,BL,FILL
3844 * Format a character at the left of the HLD output buffer.
3849 HOLD FDB DOCOL,LIT,$FFFF,HLD,PSTORE,HLD,AT,CSTORE
3854 * Give the address of the output PAD buffer.
3855 * PAD points to the end of a 68 byte buffer for numeric conversion.
3860 PAD FDB DOCOL,HERE,LIT8
3865 * ######>> screen 48 <<
3868 * Scan a string terminated by the character c or ASCII NUL out of input;
3869 * store symbol at WORDPAD with leading count byte and trailing ASCII NUL.
3870 * Leading c are passed over, per ENCLOSE.
3871 * Scans from BLK, or from TIB if BLK is zero.
3872 * May overwrite the numeric conversion pad,
3873 * if really long (length > 31) symbols are scanned.
3878 WORD FDB DOCOL,BLK,AT,ZBRAN
3880 FDB BLK,AT,BLOCK,BRAN
3883 WORD3 FDB IN,AT,PLUS,SWAP,ENCLOS,HERE,LIT8
3885 FDB BLANKS,IN,PSTORE,OVER,SUB,TOR,R,HERE
3886 FDB CSTORE,PLUS,HERE,ONEP,FROMR,CMOVE
3889 * ######>> screen 49 <<
3891 * ( d1 string --- d2 adr )
3892 * Convert the text at string into a number, accumulating the result into d1,
3893 * leaving adr pointing to the first character not converted.
3894 * If DPL is non-negative at entry,
3895 * accumulates the number of characters converted into DPL.
3897 FCC '(NUMBER' ; '(NUMBER)'
3901 PNUMB2 FDB ONEP,DUP,TOR,CAT,BASE,AT,DIGIT,ZBRAN
3903 FDB SWAP,BASE,AT,USTAR,DROP,ROT,BASE
3904 FDB AT,USTAR,DPLUS,DPL,AT,ONEP,ZBRAN
3907 PNUMB3 FDB FROMR,BRAN
3914 * Convert text at ctstr to a double integer,
3915 * taking the 0 ERROR if the conversion is not valid.
3916 * If a decimal point is present,
3917 * accumulate the count of digits to the decimal point's right into DPL
3918 * (negative DPL at exit indicates single precision).
3919 * ctstr is a counted string
3920 * -- the first byte at ctstr is the length of the string,
3921 * but NUMBER ignores the count and expects a NUL terminator instead.
3923 FCC 'NUMBE' ; 'NUMBER'
3926 NUMB FDB DOCOL,ZERO,ZERO,ROT,DUP,ONEP,CAT,LIT8
3928 FDB EQUAL,DUP,TOR,PLUS,LIT,$FFFF
3929 NUMB1 FDB DPL,STORE,PNUMB,DUP,CAT,BL,SUB
3934 FDB SUB,ZERO,QERR,ZERO,BRAN
3936 NUMB2 FDB DROP,FROMR,ZBRAN
3942 * ( --- locptr length true ) { -FIND name } typical input
3944 * Parse a word, then FIND,
3945 * first in the definition vocabulary,
3946 * then in the CONTEXT (interpretation) vocabulary, if necessary.
3947 * Returns what (FIND) returns, flag and optional location and length.
3949 FCC '-FIN' ; '-FIND'
3952 DFIND FDB DOCOL,BL,WORD,HERE,CONTXT,AT,AT
3953 FDB PFIND,DUP,ZEQU,ZBRAN
3955 FDB DROP,HERE,LATEST,PFIND
3958 * ######>> screen 50 <<
3960 * ( anything --- nothing ) ( anything *** nothing )
3961 * An indirection for ABORT, for ERROR,
3962 * which may be modified carefully.
3964 FCC '(ABORT' ; '(ABORT)'
3967 PABORT FDB DOCOL,ABORT
3972 FCC 'ERRO' ; 'ERROR'
3975 * This really should not be high level, according to best practices.
3976 * But fixing that cascades through MESSAGE,
3977 * requiring re-architecting the disk block system.
3978 * First, we need to get this transliteration running.
3979 ERROR FDB DOCOL,WARN,AT,ZLESS
3984 * 0 to print error #
3985 * and 1 to print error message from disc
3987 ERROR2 FDB HERE,COUNT,TYPE,PDOTQ
3990 FDB MESS,SPSTOR,IN,AT,BLK,AT,QUIT
3995 * Mask byte at adr with n.
3996 * Not in FIG, don't need it for 8 bit characters after all.
3998 * FCC 'CMAS' ; 'CMASK'
4001 * CMASK FDB *+NATWID
4009 * Mask high bit of tail of name in PAD buffer.
4010 * Not in FIG, need it for 8 bit characters.
4012 FCC 'IDFLA' ; 'IDFLAT'
4017 LDB ,X ; get the count
4019 LDA B,X ; point to the tail
4020 ANDA #$7F ; Clear the EndOfName flag bit.
4025 * Print definition's name from its NFA.
4030 IDDOT FDB DOCOL,PAD,LIT8
4033 FCB $5F ( underline )
4034 FDB FILL,DUP,PFA,LFA,OVER,SUB,PAD
4035 * FDB SWAP,CMOVE,PAD,COUNT,LIT8
4043 * ######>> screen 51 <<
4045 * ( --- ) { CREATE name } input
4046 * Parse a name (length < 32 characters) and create a header,
4047 * reporting first duplicate found in either the defining vocabulary
4048 * or the context (interpreting) vocabulary.
4049 * Install the header in the defining vocabulary
4050 * with CFA dangerously pointing to the parameter field.
4051 * Leave the name SMUDGEd.
4053 FCC 'CREAT' ; 'CREATE'
4056 CREATE FDB DOCOL,DFIND,ZBRAN
4065 CREAT2 FDB HERE,DUP,CAT,WIDTH,AT,MIN
4066 FDB ONEP,ALLOT,DUP,LIT8
4067 FCB ($80|FSMUDG) ; Bracket the name.
4068 FDB TOGGLE,HERE,ONE,SUB,LIT8
4070 FDB TOGGLE,LATEST,COMMA,CURENT,AT,STORE
4071 * FDB HERE,TWOP,COMMA
4075 * ######>> screen 52 <<
4078 * { [COMPILE] name } typical use
4079 * -DFIND next WORD and COMPILE it, literally;
4080 * used to compile immediate definitions into words.
4082 FCC '[COMPILE' ; '[COMPILE]'
4085 BCOMP FDB DOCOL,DFIND,ZEQU,ZERO,QERR,DROP,CFA,COMMA
4089 * ( n --- ) if compiling. P
4090 * ( n --- n ) if interpreting.
4091 * Compile n as a literal, if compiling.
4093 FCC 'LITERA' ; 'LITERAL'
4096 LITER FDB DOCOL,STATE,AT,ZBRAN
4098 FDB COMPIL,LIT,COMMA
4102 * ( d --- ) if compiling. P
4103 * ( d --- d ) if interpreting.
4104 * Compile d as a double literal, if compiling.
4106 FCC 'DLITERA' ; 'DLITERAL'
4109 DLITER FDB DOCOL,STATE,AT,ZBRAN
4111 FDB SWAP,LITER,LITER ; Just two literals in the right order.
4114 * ######>> screen 53 <<
4117 * Interpret or compile, according to STATE.
4118 * Searches words parsed in dictionary first, via -FIND,
4119 * then checks for valid NUMBER.
4120 * Pushes or COMPILEs double literal if NUMBER leaves DPL non-negative.
4121 * ERROR checks the stack via ?STACK before returning to its caller.
4123 FCC 'INTERPRE' ; 'INTERPRET'
4127 INTER2 FDB DFIND,ZBRAN
4137 INTER5 FDB HERE,NUMB,DPL,AT,ONEP,ZBRAN
4141 INTER6 FDB DROP,LITER
4142 INTER7 FDB QSTACK,BRAN
4144 * FDB SEMIS never executed
4147 * ######>> screen 54 <<
4150 * Toggle precedence bit of LATEST definition header.
4151 * During compiling, most symbols scanned are compiled.
4152 * IMMEDIATE definitions execute whenever the outer INTERPRETer scans them,
4153 * but may be compiled via ' (TICK).
4155 FCC 'IMMEDIAT' ; 'IMMEDIATE'
4158 IMMED FDB DOCOL,LATEST,LIT8
4164 * ( --- ) { VOCABULARY name } input
4165 * Create a vocabulary entry with a flag for terminating vocabulary searches.
4166 * Store the current search context in it for linking.
4167 * At run-time, VOCABULARY makes itself the CONTEXT vocabulary.
4169 FCC 'VOCABULAR' ; 'VOCABULARY'
4172 VOCAB FDB DOCOL,BUILDS,LIT,$81A0,COMMA,CURENT,AT,CFA
4173 FDB COMMA,HERE,VOCLIN,AT,COMMA,VOCLIN,STORE,DOES
4174 * DOVOC FDB TWOP,CONTXT,STORE
4175 DOVOC FDB NATP,CONTXT,STORE
4180 * Note: FORTH does not go here in the rom-able dictionary,
4181 * since FORTH is a type of variable.
4183 * (Should make a proper architecture for this at some point.)
4188 * Makes the current interpretation CONTEXT vocabulary
4189 * also the CURRENT defining vocabulary.
4191 FCC 'DEFINITION' ; 'DEFINITIONS'
4194 DEFIN FDB DOCOL,CONTXT,AT,CURENT,STORE
4199 * Parse out a comment and toss it away.
4200 * Leaves the first 32 characters in WORDPAD, which may or may not be useful.
4204 PAREN FDB DOCOL,LIT8
4209 * ######>> screen 55 <<
4211 * ( anything *** nothing )
4212 * Clear return stack.
4213 * Then INTERPRET and, if not compiling, prompt with OK,
4219 QUIT FDB DOCOL,ZERO,BLK,STORE
4222 * Here is the outer interpretter
4223 * which gets a line of input, does it, prints " OK"
4225 QUIT2 FDB RPSTOR,CR,QUERY,INTERP,STATE,AT,ZEQU
4233 * FDB SEMIS ( never executed )
4236 * ( anything --- nothing ) ( anything *** nothing )
4237 * Clear parameter stack,
4238 * set STATE to interpret and BASE to DECIMAL,
4239 * return to input from terminal,
4240 * restore DRIVE OFFSET to 0,
4241 * print out "Forth-68",
4242 * set interpret and define vocabularies to FORTH,
4243 * and finally, QUIT.
4244 * Used to force the system to a known state
4245 * and return control to the initial INTERPRETer.
4247 FCC 'ABOR' ; 'ABORT'
4250 ABORT FDB DOCOL,SPSTOR,DEC,QSTACK,DRZERO,CR,PDOTQ
4255 * FDB SEMIS never executed
4258 * ######>> screen 56 <<
4259 * bootstrap code... moves rom contents to ram :
4266 * Ultimately, we want position indepence,
4267 * so I'm using PCR where it seems reasonable.
4268 CENT LDS SINIT,PCR ; Get a useable return stack, at least.
4269 LDA #IUPDP ; This is not relative to PC.
4270 TFR A,DP ; And a useable direct page, too.
4271 SETDP IUPDP ; (For good measure.)
4273 * We'll keep this here for the time being.
4274 * There are better ways to do this, of course.
4275 * Re-architect, re-architect.
4276 LEAX ERAM,PCR ; end of stuff to move
4277 STX <XFENCE ; Borrow this variable for a loop terminator.
4278 LDY #RBEG ; bottom of open-ended destination
4279 LEAX RAM,PCR ; bottom of stuff to move
4281 STA ,Y+ ; move TASK & FORTH to ram
4284 * Leaves USE and PREV uninitialized.
4289 * STX <XFENCE ; Borrow this variable for a loop terminator.
4290 * LEAY REND,PCR ; top of destination (included XUSE and XPREV)
4291 * LEAX ERAM,PCR ; top of stuff to move (included initializers for XUSE and XPREV)
4293 * STA ,-Y ; move TASK & FORTH to ram
4297 * CENT LDS #REND-1 top of destination
4298 * LDX #ERAM top of stuff to move
4301 * PSHS A ; move TASK & FORTH to ram
4305 * LDS #XFENCE-1 put stack at a safe place for now
4306 * But that is taken care of.
4328 WENT LDS SINIT,PCR ; Get a useable return stack, at least.
4329 LDA #IUPDP ; This is not relative to PC.
4330 TFR A,DP ; And a useable direct page, too.
4331 SETDP IUPDP ; (For good measure.)
4334 PSHS X ; for loop termination
4335 CLRB ; Yes, I'm being a little ridiculous. Only a little.
4337 LEAY XFENCE-UORIG,Y ; top of destination
4338 LEAX FENCIN,PCR ; top of stuff to move
4339 WARM2 LDD ,--X ; All entries are 16 bit.
4343 LEAS 2,S ; But we'll reset the return stack shortly, anyway.
4344 LDU <XSPZER ; So we can clear the hole above the TOS
4345 * WENT LDS #XFENCE-1 top of destination
4346 * LDX #FENCIN top of stuff to move
4354 * S is already there.
4356 * STX UP init user ram pointer
4357 * UP is already there (DP).
4360 LEAY ABORT+NATWID,PCR ; IP never points to DOCOL!
4362 NOP Here is a place to jump to special user
4363 NOP initializations such as I/0 interrups
4366 * For systems with TRACE:
4368 STX ,U The hole above the parameter stack
4369 * STX TRLIM clear trace mode
4370 STX <TRLIM clear trace mode (both bytes)
4372 * STX BRKPT clear breakpoint address
4373 STX <BRKPT clear breakpoint address
4374 * JMP RPSTOR+2 start the virtual machine running !
4375 LBSR RPSTOR+NATWID start the virtual machine running !
4376 LEAX WENT,PCR ; But we must also give RP! someplace to return.
4377 STX ,S ; This rail might get walked on by (DO).
4379 * RP! sets up the return stack pointer, then Y references abort.
4381 * Here is the stuff that gets copied to ram :
4382 * (not * at address $140:)
4383 * at an appropriate address:
4385 * RAM FDB $3000,$3000,0,0
4386 * RAM FDB BUFBAS,BUFBAS,0,0 ; ... except the direct page has moved.
4387 * These initialization values for USE and PREV were here to help pack the code.
4388 * They don't belong here unless we move the USER table
4389 * back below the writable dictionary,
4390 * *and* move these USER variables to the end of the direct page --
4391 * *or* let these definitions exist in the USER table.
4396 * Makes FORTH the current interpretation vocabulary.
4397 * In order to make this ROMmable, this entry is set up as the tail-end,
4398 * and copied to RAM in the start-up code.
4399 * We want a more elegant solution to this, too. Greedy, maybe.
4401 FCC 'FORT' ; 'FORTH'
4403 FDB NOOP-7 ; Note that this does not link to COLD!
4404 RFORTH FDB DODOES,DOVOC,$81A0,TASK-7
4406 FCC "Copyright 1979 Forth Interest Group, David Lion,"
4408 FCC "Parts Copyright 2019 Joel Matthew Rees"
4414 RTASK FDB DOCOL,SEMIS
4416 ERAMSZ EQU *-RAM ; So we can get a look at it.
4419 * ######>> screen 57 <<
4422 * Sign extend n0 to a double integer.
4426 FDB COLD-7 ; Note that this does not link to FORTH (RFORTH)!
4427 STOD FDB DOCOL,DUP,ZLESS,MINUS
4433 * ( multiplier multiplicand --- product )
4434 * Signed word multiply.
4439 LBSR USTAR+NATWID ; or [USTAR,PCR]?
4440 LEAU NATWID,U ; Drop high word.
4448 * ( dividend divisor --- remainder quotient )
4449 * M/ in word-only form, i. e., signed division of 2nd word by top word,
4450 * yielding signed word quotient and remainder.
4451 * Except *BUG* it isn't signed.
4456 SLMOD FDB DOCOL,TOR,STOD,FROMR,USLASH
4460 * ( dividend divisor --- quotient )
4461 * Signed word divide without remainder.
4462 * Except *BUG* it isn't signed.
4466 SLASH FDB DOCOL,SLMOD,SWAP,DROP
4470 * ( dividend divisor --- remainder )
4471 * Remainder function, result takes sign of dividend.
4476 MOD FDB DOCOL,SLMOD,DROP
4480 * ( multiplier multiplicand divisor --- remainder quotient )
4481 * Signed precise division of product:
4482 * multiply 2nd and 3rd words on stack
4483 * and divide the 31-bit product by the top word,
4484 * leaving both quotient and remainder.
4485 * Remainder takes sign of product.
4486 * Guaranteed not to lose significant bits in 16 bit integer math.
4488 FCC '*/MO' ; '*/MOD'
4491 SSMOD FDB DOCOL,TOR,USTAR,FROMR,USLASH
4495 * ( multiplier multiplicand divisor --- quotient )
4496 * */MOD without remainder.
4501 SSLASH FDB DOCOL,SSMOD,SWAP,DROP
4505 * ( ud1 u1 --- u2 ud2 )
4506 * U/ with an (unsigned) double quotient.
4507 * Guaranteed not to lose significant bits in 32 bit / 16 bit bit integer math,
4508 * if you are prepared to deal with the extra 16 bits of result.
4510 FCC 'M/MO' ; 'M/MOD'
4513 MSMOD FDB DOCOL,TOR,ZERO,R,USLASH
4514 FDB FROMR,SWAP,TOR,USLASH,FROMR
4520 * Convert the top of stack to its absolute value.
4525 ABS FDB DOCOL,DUP,ZLESS,ZBRAN
4533 * Convert the top double to its absolute value.
4538 DABS FDB DOCOL,DUP,ZLESS,ZBRAN
4543 * ######>> screen 58 <<
4547 * Least Recently Used buffer.
4548 * Really should be with FIRST and LIMIT in the per-task table.
4557 * Most Recently Used buffer.
4558 * Really should be with FIRST and LIMIT in the per-task table.
4566 * ( buffer1 --- buffer2 f )
4567 * Bump to next buffer,
4568 * flag false if result is PREVious buffer,
4569 * otherwise flag true.
4570 * Used in the LRU allocation routines.
4575 * PBUF FDB DOCOL,LIT8
4576 * FCB $84 ; This was a hard-wiring bug.
4577 PBUF FDB DOCOL,BBUF,BCTL,PLUS ; Size of the buffer record.
4578 * FDB PLUS,DUP,LIMIT,EQUAL,ZBRAN
4579 FDB PLUS,DUP,LIMIT,LESS,ZEQU,OVER,FIRST,LESS,OR,ZBRAN
4580 FDB PBUF2-*-NATWID ; Use defensive programming.
4582 PBUF2 FDB DUP,PREV,AT,SUB
4587 * Flag to mark a buffer dirty, in need of being written out.
4588 * This flag limits the max number of sectors in a disk to ((256^NATWID)/2)-1.
4589 * It also hard-codes an implicit test which is used elsewhere.
4591 FCC 'UPDATE-BI' ; 'UPDATE-BIT'
4598 * Mark PREVious buffer dirty, in need of being written out.
4600 FCC 'UPDAT' ; 'UPDATE'
4603 * UPDATE FDB DOCOL,PREV,AT,AT,LIT,$8000,OR,PREV,AT,STORE
4604 UPDATE FDB DOCOL,PREV,AT,AT,UPDBIT,OR,PREV,AT,STORE
4609 * Mark the buffer addressed as empty.
4610 * Have to add code to avoid block 0 appearing to be in a buffer from COLD.
4611 * Usually, there is no sector 0 (?), but the RAM buffers are too simple.
4612 * Note that without this block number being made illegal,
4613 * about 8 binaryMegabytes (256 bytes/block) of disk can be addressed total.
4614 * With this block number made illegal, the max is 1 block less,
4615 * still about 8 biMeg.
4617 FCC 'KILL-BUFFE' ; 'KILL-BUFFER'
4620 KILBUF FDB *+NATWID ; DOCOL,UPDBIT,ONE,SUB,SWAP,STORE
4622 LDD UPDBIT+NATWID,PCR
4629 FCC 'KILL-BUFFER' ; 'KILL-BUFFERS'
4635 LDD FIRST+NATWID,PCR
4643 ADDD BBUF+NATWID,PCR
4644 ADDD BCTL+NATWID,PCR
4655 * Erase and mark all buffers empty.
4656 * Standard method of discarding changes.
4658 FCC 'EMPTY-BUFFER' ; 'EMPTY-BUFFERS'
4661 MTBUF FDB DOCOL,FIRST,LIMIT,OVER,SUB,ERASE
4662 * FDB FIRST,DUP,KILBUF,PBUF,DROP,DUP,KILBUF
4663 * FDB PBUF,DROP,DUP,KILBUF,PBUF,DROP,KILBUF
4669 * Clear the current offset to the block numbers in the drive interface.
4670 * The drives need to be re-architected.
4671 * Would be cool to have RAM and ROM drives supported
4672 * in addition to regular physical persistent store.
4677 DRZERO FDB DOCOL,ZERO,OFSET,STORE
4680 * ======>> 174 <<== system dependant word
4682 * Set the current offset in the drive interface to reference the second drive.
4683 * The hard-coded number in there needs to be in a table.
4688 DRONE FDB DOCOL,LIT,$07D0,OFSET,STORE
4689 ; **** hard-codes the size of the disc !!!!
4692 * ######>> screen 59 <<
4695 * Get a free buffer,
4696 * assign it to block n,
4697 * return buffer address.
4698 * Will free a buffer by writing it, if necessary.
4699 * Does not actually read the block.
4700 * A bug in the fig LRU algorithm, which I have not fixed,
4701 * gives the PREVious buffer if USE gets set to PREVious.
4702 * (The bug is that USE sometimes gets set to PREVious.)
4703 * This bug sometimes causes sector moves to become sector fills.
4705 FCC 'BUFFE' ; 'BUFFER'
4708 BUFFER FDB DOCOL,USE,AT,DUP,TOR
4709 BUFFR2 FDB PBUF,ZBRAN
4711 FDB USE,STORE,R,AT,ZLESS
4714 * FDB R,TWOP,R,AT,LIT,$7FFF,AND,ZERO,RW
4715 FDB R,NATP,R,AT,UPDBIT,LNOT,AND,ZERO,RW
4716 * BUFFR3 FDB R,STORE,R,PREV,STORE,FROMR,TWOP
4717 BUFFR3 FDB R,STORE,R,PREV,STORE,FROMR,NATP
4720 * ######>> screen 60 <<
4723 * Get BUFFER containing block n, relative to OFFSET.
4724 * If block n is not in a buffer, bring it in.
4725 * Returns buffer address.
4727 FCC 'BLOC' ; 'BLOCK'
4730 BLOCK FDB DOCOL,OFSET,AT,PLUS,TOR
4731 FDB PREV,AT,DUP,AT,R,SUB,DUP,PLUS,ZBRAN
4733 BLOCK3 FDB PBUF,ZEQU,ZBRAN
4735 * FDB DROP,R,BUFFER,DUP,R,ONE,RW,TWO,SUB
4736 FDB DROP,R,BUFFER,DUP,R,ONE,RW,NATWC,SUB
4737 BLOCK4 FDB DUP,AT,R,SUB,DUP,PLUS,ZEQU,ZBRAN
4740 * BLOCK5 FDB FROMR,DROP,TWOP
4741 BLOCK5 FDB FROMR,DROP,NATP
4744 * ######>> screen 61 <<
4746 * ( line screen --- buffer C/L)
4747 * Bring in the sector containing the specified line of the specified screen.
4748 * Returns the buffer address and the width of the screen.
4749 * Screen number is relative to OFFSET.
4750 * The line number may be beyond screen 4,
4751 * (LINE) will get the appropriate screen.
4753 FCC '(LINE' ; '(LINE)'
4756 PLINE FDB DOCOL,TOR,LIT8
4758 FDB BBUF,SSMOD,FROMR,BSCR,STAR,PLUS,BLOCK,PLUS,LIT8
4763 * ( line screen --- )
4764 * Print the line of the screen as found by (LINE), suppress trailing BLANKS.
4766 FCC '.LIN' ; '.LINE'
4769 DLINE FDB DOCOL,PLINE,DTRAIL,TYPE
4774 * If WARNING is 0, print "MESSAGE #n";
4775 * otherwise, print line n relative to screen 4,
4776 * the line number may be negative.
4777 * Uses .LINE, but counter-adjusts to be relative to the real drive 0.
4779 FCC 'MESSAG' ; 'MESSAGE'
4782 MESS FDB DOCOL,WARN,AT,ZBRAN
4788 FDB OFSET,AT,BSCR,SLASH,SUB,DLINE,BRAN
4792 FCC 'err # ' ; 'err # '
4798 * Begin interpretation of screen (block) n.
4799 * See also ARROW, SEMIS, and NULL.
4801 FCC 'LOA' ; 'LOAD' : input:scr #
4804 LOAD FDB DOCOL,BLK,AT,TOR,IN,AT,TOR,ZERO,IN,STORE
4805 FDB BSCR,STAR,BLK,STORE
4806 FDB INTERP,FROMR,IN,STORE,FROMR,BLK,STORE
4811 * Continue interpreting source code on the next screen.
4816 ARROW FDB DOCOL,QLOAD,ZERO,IN,STORE,BSCR
4817 FDB BLK,AT,OVER,MOD,SUB,BLK,PSTORE
4822 * ######>> screen 63 <<
4823 * The next 4 subroutines are machine dependent, and are
4824 * called by words 13 through 16 in the dictionary.
4826 * ======>> 182 << code for EMIT
4827 * ( --- ) No parameter stack effect.
4828 * Interfaces directly with ROM. Expects output character in D (therefore, B).
4829 * Output using rom CHROUT: redirectable to a printer on Coco.
4830 * Outputs the character on stack (low byte of 1 bit word/cell).
4831 PEMIT PSHS Y,U,DP ; Save everything important! (For good measure, only.)
4832 TFR B,A ; Coco ROM wants it in A.
4834 TFR B,DP ; Give the ROM its direct page.
4835 JSR [$A002] ; Output the character in A.
4837 * PEMIT STB N save B
4840 * BITB #2 check ready bit
4841 * BEQ PEMIT+4 if not ready for more data
4844 * STB IOSTAT-UORIG,X
4845 * LDB N recover B & X
4847 * RTS only A register may change
4848 * PEMIT JMP $E1D1 for MIKBUG
4849 * PEMIT FCB $3F,$11,$39 for PROTO
4850 * PEMIT JMP $D286 for Smoke Signal DOS
4852 * ======>> 183 << code for KEY
4853 * ( --- ) No parameter stack effect.
4854 * Returns character or break flag in D, since this interfaces with Coco ROM.
4855 * Wait for key from POLCAT on Coco.
4856 * Returns the character code for the key pressed.
4857 PKEY PSHS Y,U,DP ; Must save everything important for this one.
4858 LDA #$CF ; a cursor of sorts
4870 PKEYR CLRB ; for the break flag, shares code with PQTER
4873 COMB ; for the break flag
4874 PKEYGT EXG A,B ; Leave it in D for return.
4875 PULS Y,U,DP,PC ; Shares exit with PQTER
4881 * BCC PKEY+4 no incoming data yet
4883 * ANDA #$7F strip parity bit
4885 * STB IOSTAT+1-UORIG,X
4889 * PKEY JMP $E1AC for MIKBUG
4890 * PKEY FCB $3F,$14,$39 for PROTO
4891 * PKEY JMP $D289 for Smoke Signal DOS
4893 * ######>> screen 64 <<
4894 * ======>> 184 << code for ?TERMINAL
4895 * ( --- f ) Should change this to no stack effect.
4896 * check break key using POLCAT
4897 * Returns a flag to tell whether the break key was pressed or not.
4901 JSR [$A000] ; Look but don't wait.
4903 * PQTER LDA ACIAC Test for 'break' condition
4904 * ANDA #$11 mask framing error bit and
4907 * LDA ACIAD clear input buffer
4914 * ======>> 185 << code for CR
4915 * ( --- ) No stack effect.
4916 * Interfaces directly with ROM.
4917 * For Coco just output a CR.
4918 * Also subject to redirection in Coco BASIC ROM.
4920 BRA PEMIT ; Just steal the code.
4921 * PCR LDA #$D carriage return
4927 * LDB XDELAY+1-UORIG,X
4929 * BMI PQTER2 return if minus
4930 * PSHS B ; save counter
4931 * BSR PEMIT print RUBOUTs to delay.....
4938 * ######>> screen 66 <<
4941 * Query the disk, I suppose.
4942 * Not sure what the model had in mind for this stub.
4944 FCC '?DIS' ; '?DISC'
4950 * ######>> screen 67 <<
4953 * Write one block of data to disk.
4954 * Parameters unspecified in model. Stub in model.
4956 FCC 'BLOCK-WRIT' ; 'BLOCK-WRITE'
4962 * ######>> screen 68 <<
4965 * Read one block of data from disk.
4966 * Parameters unspecified in model. Stub in model.
4968 FCC 'BLOCK-REA' ; 'BLOCK-READ'
4974 *The next 3 words are written to create a substitute for disc
4975 * mass memory,located between MASSLO & MASSHI in ram --
4976 * ($3210 and $3fff in the 6800 model).
4983 FDB MEMEND a system dependent equate at front
4991 FDB MEMTOP ( $3FFF or $7FFF in this version )
4993 * ######>> screen 69 <<
4995 * ( buffer sector f --- )
4996 * Read or Write the specified (absolute -- ignores OFFSET) sector
4997 * from or to the specified buffer.
4998 * A zero flag specifies write,
4999 * non-zero specifies read.
5000 * Sector is an unsigned integer,
5001 * buffer is the buffer's address.
5002 * Will need to use the CoCo ROM disk routines.
5003 * For now, provides a virtual disk in RAM.
5008 RW FDB DOCOL,TOR,BBUF,STAR,LO,PLUS,DUP,HI,GREAT,ZBRAN
5012 FCC ' Range ?' ; ' Range ?'
5022 * LDY $C006 control table
5023 * LDX #DROFFS+7 ; This is BIF's table of drive sizes.
5025 * RWD SUBD ,X++ sectors
5027 * BVC RWR table end?
5031 * RWR ADDD ,--X back one
5034 * LDD #18 sectors/track
5044 * PULS D table entry
5057 * JSR [$C004] ROM handles timeout
5058 * PULS Y,U,DP if IRQ enabled
5061 * LDB 6,X coco status
5071 * ######>> screen 72 <<
5073 * ( --- ) compiling P
5074 * ( --- adr ) interpreting
5076 * Parse a symbol name from input and search the dictionary for it, per -FIND;
5077 * compile the address as a literal if compiling,
5078 * otherwise just push it.
5082 TICK FDB DOCOL,DFIND,ZEQU,ZERO,QERR,DROP,LITER
5086 * ( --- ) { FORGET name } input
5087 * Parse out name of definition to FORGET to, -DFIND it,
5088 * then lop it and everything that follows out of the dictionary.
5089 * In fig Forth, CURRENT and CONTEXT have to be the same to FORGET.
5091 FCC 'FORGE' ; 'FORGET'
5094 FORGET FDB DOCOL,CURENT,AT,CONTXT,AT,SUB,LIT8
5096 FDB QERR,TICK,DUP,FENCE,AT,LESS,LIT8
5098 FDB QERR,DUP,ZERO,PORIG,GREAT,LIT8
5100 FDB QERR,DUP,NFA,DICTPT,STORE,LFA,AT,CONTXT,AT,STORE
5103 * ######>> screen 73 <<
5106 * Calculate a back reference from HERE and compile it.
5111 * BACK FDB DOCOL,HERE,SUB,COMMA
5112 BACK FDB DOCOL,HERE,NATP,SUB,COMMA
5117 * typical use: BEGIN code-loop test UNTIL
5118 * typical use: BEGIN code-loop AGAIN
5119 * typical use: BEGIN code-loop test WHILE code-true REPEAT
5120 * ( --- adr n ) compile time P,C
5121 * Push HERE for BACK reference for general (non-counting) loops,
5122 * with BEGIN construct flag.
5123 * A better flag: $4245 (ASCII for 'BE').
5125 FCC 'BEGI' ; 'BEGIN'
5128 BEGIN FDB DOCOL,QCOMP,HERE,ONE ; ONE is a flag for BEGIN loops.
5133 * typical use: test IF code-true ELSE code-false ENDIF
5134 * ENDIF is just a sort of intersection piece,
5135 * marking where execution resumes after both branches.
5136 * ( adr n --- ) compile time
5137 * Check the mark and resolve the IF.
5138 * A better flag: $4846 (ASCII for 'IF').
5140 FCC 'ENDI' ; 'ENDIF'
5143 ENDIF FDB DOCOL,QCOMP,TWO,QPAIRS,HERE ; This TWO is a flag for IF.
5144 FDB OVER,NATP,SUB,SWAP,STORE
5149 * typical use: test IF code-true ELSE code-false ENDIF
5156 THEN FDB DOCOL,ENDIF
5160 * ( limit index --- ) runtime
5161 * typical use: DO code-loop LOOP
5162 * typical use: DO code-loop increment +LOOP
5163 * Counted loop, index is initial value of index.
5164 * Will loop until index equals (positive going)
5165 * or passes (negative going) limit.
5166 * ( --- adr n ) compile time P,C
5167 * Compile (DO), push HERE for BACK reference,
5168 * and push DO control construct flag.
5169 * A better flag: $444F (ASCII for 'DO').
5174 DO FDB DOCOL,COMPIL,XDO,HERE,THREE ; THREE is a flag for DO loops.
5179 * typical use: DO code-loop LOOP
5180 * Increments the index by one and branches back to beginning of loop.
5181 * Will loop until index equals limit.
5182 * ( adr n --- ) compile time P,C
5183 * Check the mark and compile (LOOP), fill in BACK reference.
5184 * A better flag: $444F (ASCII for 'DO').
5189 LOOP FDB DOCOL,THREE,QPAIRS,COMPIL,XLOOP,BACK ; THREE for DO loops.
5194 * typical use: DO code-loop increment +LOOP
5195 * Increments the index by n and branches back to beginning of loop.
5196 * Will loop until index equals (positive going)
5197 * or passes (negative going) limit.
5198 * ( adr n --- ) compile time P,C
5199 * Check the mark and compile (+LOOP), fill in BACK reference.
5200 * A better flag: $444F (ASCII for 'DO').
5202 FCC '+LOO' ; '+LOOP'
5205 PLOOP FDB DOCOL,THREE,QPAIRS,COMPIL,XPLOOP,BACK ; THREE for DO loops.
5210 * typical use: BEGIN code-loop test UNTIL
5211 * Will loop until UNTIL tests true.
5212 * ( adr n --- ) compile time P,C
5213 * Check the mark and compile (0BRANCH), fill in BACK reference.
5214 * A better flag: $4245 (ASCII for 'BE').
5216 FCC 'UNTI' ; 'UNTIL' : ( same as END )
5219 UNTIL FDB DOCOL,ONE,QPAIRS,COMPIL,ZBRAN,BACK ; ONE for BEGIN loops.
5222 * ######>> screen 74 <<
5225 * typical use: BEGIN code-loop test END
5237 * typical use: BEGIN code-loop AGAIN
5239 * (or until something uses R> DROP to force the current definition to die,
5240 * or perhaps ABORT or ERROR or some such other drastic means stops things).
5241 * ( adr n --- ) compile time P,C
5242 * Check the mark and compile (0BRANCH), fill in BACK reference.
5243 * A better flag: $4245 (ASCII for 'BE').
5245 FCC 'AGAI' ; 'AGAIN'
5248 AGAIN FDB DOCOL,ONE,QPAIRS,COMPIL,BRAN,BACK ; ONE for BEGIN loops.
5253 * typical use: BEGIN code-loop test WHILE code-true REPEAT
5254 * Will loop until WHILE tests false, skipping code-true on end.
5255 * REPEAT marks where execution resumes after the WHILE find a false flag.
5256 * ( aadr1 n1 adr2 n2 --- ) compile time P,C
5257 * Check the marks for WHILE and BEGIN,
5258 * compile BRANCH and BACK fill adr1 reference,
5259 * FILL-IN 0BRANCH reference at adr2.
5260 * Better flags: $4245 (ASCII for 'BE') and $5747 (ASCII for 'WH').
5262 FCC 'REPEA' ; 'REPEAT'
5265 REPEAT FDB DOCOL,TOR,TOR,AGAIN,FROMR,FROMR ; ONE for BEGIN loops.
5266 FDB TWO,SUB,ENDIF ; TWO is for IF, 4 is for WHILE.
5271 * typical use: test IF code-true ELSE code-false ENDIF
5272 * Will pass execution to the true part on a true flag
5273 * and to the false part on a false flag.
5274 * ( --- adr n ) compile time P,C
5275 * Compile a 0BRANCH and dummy offset
5276 * and push IF reference to fill in and
5277 * IF control construct flag.
5278 * A better flag: $4946 (ASCII for 'IF').
5283 IF FDB DOCOL,COMPIL,ZBRAN,HERE,ZERO,COMMA,TWO ; TWO is a flag for IF.
5288 * typical use: test IF code-true ELSE code-false ENDIF
5289 * ELSE is just a sort of intersection piece,
5290 * marking where execution resumes on a false branch.
5291 * ( adr1 n --- adr2 n ) compile time P,C
5293 * compile BRANCH with dummy offset,
5294 * resolve IF reference,
5295 * and leave reference to BRANCH for ELSE.
5296 * A better flag: $4946 (ASCII for 'IF').
5301 ELSE FDB DOCOL,TWO,QPAIRS,COMPIL,BRAN,HERE
5302 FDB ZERO,COMMA,SWAP,TWO,ENDIF,TWO ; TWO is a flag for IF.
5307 * typical use: BEGIN code-loop test WHILE code-true REPEAT
5308 * Will loop until WHILE tests false, skipping code-true on end.
5309 * ( --- adr n ) compile time P,C
5310 * Compile 0BRANCH with dummy offset (using IF),
5311 * push WHILE reference.
5312 * BEGIN flag will sit underneath this.
5313 * Better flags: $4245 (ASCII for 'BE') and $5747 (ASCII for 'WH').
5315 FCC 'WHIL' ; 'WHILE'
5318 WHILE FDB DOCOL,IF,TWOP ; TWO is a flag for IF, 4 is for WHILE.
5321 * ######>> screen 75 <<
5324 * EMIT count spaces, for non-zero, non-negative counts.
5326 FCC 'SPACE' ; 'SPACES'
5329 SPACES FDB DOCOL,ZERO,MAX,DDUP,ZBRAN
5332 SPACE2 FDB SPACE,XLOOP
5338 * Initialize HLD for converting a double integer.
5339 * Stores the PAD address in HLD.
5344 BDIGS FDB DOCOL,PAD,HLD,STORE
5348 * ( d --- string length )
5349 * Terminate numeric conversion,
5350 * drop the number being converted,
5351 * leave the address of the conversion string and the length, ready for TYPE.
5356 EDIGS FDB DOCOL,DROP,DROP,HLD,AT,PAD,OVER,SUB
5361 * Put sign of n (as a flag) at the head of the conversion string.
5362 * Drop the sign flag.
5367 SIGN FDB DOCOL,ROT,ZLESS,ZBRAN
5376 * Generate next most significant digit in the conversion BASE,
5377 * putting the digit at the head of the conversion string.
5381 DIG FDB DOCOL,BASE,AT,MSMOD,ROT,LIT8
5395 * Convert d to a numeric string using # until the result is zero.
5396 * Leave the double result on the stack for #> to drop.
5402 DIGS2 FDB DIG,OVER,OVER,OR,ZEQU,ZBRAN
5406 * ######>> screen 76 <<
5409 * Print n on the output device in the current conversion base,
5411 * right aligned in a field at least width wide.
5416 DOTR FDB DOCOL,TOR,STOD,FROMR,DDOTR
5421 * Print d on the output device in the current conversion base,
5423 * right aligned in a field at least width wide.
5428 DDOTR FDB DOCOL,TOR,SWAP,OVER,DABS,BDIGS,DIGS,SIGN
5429 FDB EDIGS,FROMR,OVER,SUB,SPACES,TYPE
5434 * Print d on the output device in the current conversion base,
5436 * in free format with trailing space.
5441 DDOT FDB DOCOL,ZERO,DDOTR,SPACE
5446 * Print n on the output device in the current conversion base,
5448 * in free format with trailing space.
5452 DOT FDB DOCOL,STOD,DDOT
5457 * Print signed word at adr, per DOT.
5461 QUEST FDB DOCOL,AT,DOT
5464 * ######>> screen 77 <<
5467 * Print out screen n as a field of ASCII,
5468 * with line numbers in decimal.
5469 * Needs a console more than 70 characters wide.
5474 LIST FDB DOCOL,DEC,CR,DUP,SCR,STORE,PDOTQ
5480 LIST2 FDB CR,I,THREE
5481 FDB DOTR,SPACE,I,SCR,AT,DLINE,XLOOP
5488 * Print comment lines (line 0, and line 1 if C/L < 41) of screens
5489 * from start to end.
5490 * Needs a console more than 70 characters wide.
5492 FCC 'INDE' ; 'INDEX'
5495 INDEX FDB DOCOL,CR,ONEP,SWAP,XDO
5496 INDEX2 FDB CR,I,THREE
5497 FDB DOTR,SPACE,ZERO,I,DLINE
5507 * List a printer page full of screens.
5508 * Line and screen number are in current base.
5509 * Needs a console more than 70 characters wide.
5511 FCC 'TRIA' ; 'TRIAD'
5514 TRIAD FDB DOCOL,THREE,SLASH,THREE,STAR
5515 FDB THREE,OVER,PLUS,SWAP,XDO
5517 FDB LIST,QTERM,ZBRAN
5527 * ######>> screen 78 <<
5530 * Alphabetically list the definitions in the current vocabulary.
5531 * Expects to output to printer, not TRS80 Color Computer screen.
5533 FCC 'VLIS' ; 'VLIST'
5536 VLIST FDB DOCOL,LIT8
5538 FDB OUT,STORE,CONTXT,AT,AT
5539 VLIST1 FDB OUT,AT,COLUMS,AT,LIT8
5543 FDB CR,ZERO,OUT,STORE
5544 VLIST2 FDB DUP,IDDOT,SPACE,SPACE,PFA,LFA,AT
5545 FDB DUP,ZEQU,QTERM,OR,ZBRAN
5550 * Need some utility stuff that isn't in the fig FORTH:
5552 * Emit dot if c is less than blank, else emit c
5554 FCC 'BEMI' ; 'BEMIT'
5558 FDB DUP,BL,LESS,ZBRAN
5566 * Output n in hexadecimal field width.
5572 FDB BASE,AT,TOR,HEX,DOTR,FROMR,BASE,STORE
5576 * Dump a line of 4 bytes in memory, in hex and as characters.
5578 FCC 'BLIN' ; 'BLINE'
5585 BLINEX FDB I,CAT,THREE,XDOTR,XLOOP
5591 BLINEC FDB I,CAT,BEMIT,XLOOP
5596 * Dump 4 byte lines from start to end.
5598 FCC 'BDUM' ; 'BDUMP'
5616 * Mostly for place holding (fig Forth).
5623 * Without the RTS, would misalign the stack.
5624 * NOOP NEXT a useful no-op
5625 ZZZZ FDB 0,0,0,0,0,0,0,0 end of rom program
5628 * These things, up through the lable 'REND', are overwritten
5629 * at time of cold load and should have the same contents
5632 * This can be moved whereever the bottom of the
5633 * user's dictionary is going to be put.
5637 FCC 'FORT' ; 'FORTH'
5640 FORTH FDB DODOES,DOVOC,$81A0,TASK-7
5643 FCC "Copyright 1979 Forth Interest Group, David Lion,"
5645 FCC "Parts Copyright 2019 Joel Matthew Rees"
5652 TASK FDB DOCOL,SEMIS
5654 REND EQU * ( first empty location in dictionary )
5655 RSIZE EQU *-RBEG ; So we can look at it.
5659 * "0 1 2 3 4 5 6 " ;
5660 * "0123456789012345678901234567890123456789012345678901234567890123" ;
5661 FCC " 0) Index page " ; 0
5662 FCC " 1) empty line on line 1 of screen 0 block 0 " ; 1
5663 FCC " 2) Title and copyright " ; 2
5664 FCC " 3) empty line on line 3 of screen 0 block 0 " ; 3
5665 FCC " 4) Error messages 1st screen " ; 4
5666 FCC " 5) Error messages 2nd screen " ; 5
5667 FCC " 6) empty line 3 screen 0 block 1 " ; 6
5668 FCC " 7) empty line 4 " ; 7
5669 FCC " 8) and line 1 of block 2 " ; 8
5670 FCC " 9) line 2 of block 2 screen 0 is pretty much empty too " ; 9
5671 FCC " 10) listen to this. Line three of block two is too " ; 10
5672 FCC " 11) and so is line 4 4 4 4 4 4 4 4 4 4 b2s0 " ; 11
5673 FCC " 12) screen zero block three first line " ; 12
5674 FCC " 13) second line fourth block (block three) screen 0 " ; 13
5675 FCC " 14) block three screen zero line 3 3 3 3 3 3 3 3 3 " ; 14
5676 FCC " 15) fourth line block three screen 0 0 0 0 0 0 0 0 0 0 " ; 15
5677 * "0 1 2 3 4 5 6 " ;
5678 * "0123456789012345678901234567890123456789012345678901234567890123" ;
5679 FCC " test 10 b0s1 aaaa " ; 0
5680 FCC " test 11 b0s1 ee ee ee ee " ; 1
5681 FCC " test 12 b0s1 oo oo oo oo oo " ; 2
5682 FCC " test 13 b0s1 eh ehe he eh eh " ; 3
5683 FCC " ( block 1 ) b1s1 oh ohoo oh oh oh " ; 4
5684 FCC " 15 test b1s1 " ; 5
5685 FCC " 16 test b1s1 " ; 6
5686 FCC " 17 test b1s1 " ; 7
5687 FCC " 18 test b2s1 " ; 8
5688 FCC " 19 test b2s1 " ; 9
5689 FCC " 1A test b2s1 " ; 10
5690 FCC " 1B test b2ws1 " ; 11
5691 FCC " 1C test b3s1 " ; 12
5692 FCC " 1D test b3s1 " ; 13
5693 FCC " 1e this completes our second screen b3s1 " ; 14
5694 FCC " 1F test b3s1 " ; 15
5695 * "0 1 2 3 4 5 6 " ;
5696 * "0123456789012345678901234567890123456789012345678901234567890123" ;
5698 FCC " fig Forth High Level Model Code " ; 1
5700 FCC " Copyright 2018 Joel Matthew Rees " ; 3
5701 FCC " ( block 2 ) " ; 4
5713 * "0 1 2 3 4 5 6 " ;
5714 * "0123456789012345678901234567890123456789012345678901234567890123" ;
5719 FCC " ( block 3 ) " ; 4
5731 * "0 1 2 3 4 5 6 " ;
5732 * "0123456789012345678901234567890123456789012345678901234567890123" ;
5737 FCC " ( block 4 ) " ; 4
5749 * "0 1 2 3 4 5 6 " ;
5750 * "0123456789012345678901234567890123456789012345678901234567890123" ;
5751 FCC " ( ERROR MESSAGES ) " ; 0
5752 FCC " DATA STACK UNDERFLOW " ; 1
5753 FCC " DICTIONARY FULL " ; 2
5754 FCC " ADDRESS RESOLUTION ERROR " ; 3
5755 FCC " HIDES DEFINITION IN " ; 4
5767 * "0 1 2 3 4 5 6 " ;
5768 * "0123456789012345678901234567890123456789012345678901234567890123" ;
5769 FCC " more test data 2 3 4 5 6 " ; 0
5770 FCC "0123456789012345678901234567890123456789012345678901234567890123" ; 1
5771 FCC "Test data for the RAM disc emulator buffers. " ; 2
5773 FCC " ( block 6 ) " ; 4