1 /* Decimal floating point support.
2 Copyright (C) 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
22 #include "coretypes.h"
30 /* The order of the following headers is important for making sure
31 decNumber structure is large enough to hold decimal128 digits. */
33 #include "decimal128.h"
34 #include "decimal128Local.h"
35 #include "decimal64.h"
36 #include "decimal32.h"
37 #include "decNumber.h"
39 /* Initialize R (a real with the decimal flag set) from DN. Can
40 utilize status passed in via CONTEXT, if a previous operation had
41 interesting status. */
44 decimal_from_decnumber (REAL_VALUE_TYPE *r, decNumber *dn, decContext *context)
46 memset (r, 0, sizeof (REAL_VALUE_TYPE));
49 if (decNumberIsNaN (dn))
51 if (decNumberIsInfinite (dn))
53 if (context->status & DEC_Overflow)
55 if (decNumberIsNegative (dn))
59 if (r->cl != rvc_normal)
62 decContextDefault (context, DEC_INIT_DECIMAL128);
65 decimal128FromNumber ((decimal128 *) r->sig, dn, context);
68 /* Create decimal encoded R from string S. */
71 decimal_real_from_string (REAL_VALUE_TYPE *r, const char *s)
75 decContextDefault (&set, DEC_INIT_DECIMAL128);
78 decNumberFromString (&dn, s, &set);
80 /* It would be more efficient to store directly in decNumber format,
81 but that is impractical from current data structure size.
82 Encoding as a decimal128 is much more compact. */
83 decimal_from_decnumber (r, &dn, &set);
86 /* Initialize a decNumber from a REAL_VALUE_TYPE. */
89 decimal_to_decnumber (const REAL_VALUE_TYPE *r, decNumber *dn)
92 decContextDefault (&set, DEC_INIT_DECIMAL128);
101 decNumberFromString (dn, "Infinity", &set);
105 decNumberFromString (dn, "snan", &set);
107 decNumberFromString (dn, "nan", &set);
110 gcc_assert (r->decimal);
111 decimal128ToNumber ((const decimal128 *) r->sig, dn);
117 /* Fix up sign bit. */
118 if (r->sign != decNumberIsNegative (dn))
122 /* Encode a real into an IEEE 754R decimal32 type. */
125 encode_decimal32 (const struct real_format *fmt ATTRIBUTE_UNUSED,
126 long *buf, const REAL_VALUE_TYPE *r)
132 decContextDefault (&set, DEC_INIT_DECIMAL128);
135 decimal_to_decnumber (r, &dn);
136 decimal32FromNumber (&d32, &dn, &set);
138 buf[0] = *(uint32_t *) d32.bytes;
141 /* Decode an IEEE 754R decimal32 type into a real. */
144 decode_decimal32 (const struct real_format *fmt ATTRIBUTE_UNUSED,
145 REAL_VALUE_TYPE *r, const long *buf)
151 decContextDefault (&set, DEC_INIT_DECIMAL128);
154 *((uint32_t *) d32.bytes) = (uint32_t) buf[0];
156 decimal32ToNumber (&d32, &dn);
157 decimal_from_decnumber (r, &dn, &set);
160 /* Encode a real into an IEEE 754R decimal64 type. */
163 encode_decimal64 (const struct real_format *fmt ATTRIBUTE_UNUSED,
164 long *buf, const REAL_VALUE_TYPE *r)
170 decContextDefault (&set, DEC_INIT_DECIMAL128);
173 decimal_to_decnumber (r, &dn);
174 decimal64FromNumber (&d64, &dn, &set);
176 buf[0] = *(uint32_t *) &d64.bytes[0];
177 buf[1] = *(uint32_t *) &d64.bytes[4];
180 /* Decode an IEEE 754R decimal64 type into a real. */
183 decode_decimal64 (const struct real_format *fmt ATTRIBUTE_UNUSED,
184 REAL_VALUE_TYPE *r, const long *buf)
190 decContextDefault (&set, DEC_INIT_DECIMAL128);
193 *((uint32_t *) &d64.bytes[0]) = (uint32_t) buf[0];
194 *((uint32_t *) &d64.bytes[4]) = (uint32_t) buf[1];
196 decimal64ToNumber (&d64, &dn);
197 decimal_from_decnumber (r, &dn, &set);
200 /* Encode a real into an IEEE 754R decimal128 type. */
203 encode_decimal128 (const struct real_format *fmt ATTRIBUTE_UNUSED,
204 long *buf, const REAL_VALUE_TYPE *r)
210 decContextDefault (&set, DEC_INIT_DECIMAL128);
213 decimal_to_decnumber (r, &dn);
214 decimal128FromNumber (&d128, &dn, &set);
216 buf[0] = *(uint32_t *) &d128.bytes[0];
217 buf[1] = *(uint32_t *) &d128.bytes[4];
218 buf[2] = *(uint32_t *) &d128.bytes[8];
219 buf[3] = *(uint32_t *) &d128.bytes[12];
222 /* Decode an IEEE 754R decimal128 type into a real. */
225 decode_decimal128 (const struct real_format *fmt ATTRIBUTE_UNUSED,
226 REAL_VALUE_TYPE *r, const long *buf)
232 decContextDefault (&set, DEC_INIT_DECIMAL128);
235 *((uint32_t *) &d128.bytes[0]) = (uint32_t) buf[0];
236 *((uint32_t *) &d128.bytes[4]) = (uint32_t) buf[1];
237 *((uint32_t *) &d128.bytes[8]) = (uint32_t) buf[2];
238 *((uint32_t *) &d128.bytes[12]) = (uint32_t) buf[3];
240 decimal128ToNumber (&d128, &dn);
241 decimal_from_decnumber (r, &dn, &set);
244 /* Helper function to convert from a binary real internal
248 decimal_to_binary (REAL_VALUE_TYPE *to, const REAL_VALUE_TYPE *from,
249 enum machine_mode mode)
252 const decimal128 *const d128 = (const decimal128 *) from->sig;
254 decimal128ToString (d128, string);
255 real_from_string3 (to, string, mode);
259 /* Helper function to convert from a binary real internal
263 decimal_from_binary (REAL_VALUE_TYPE *to, const REAL_VALUE_TYPE *from)
267 /* We convert to string, then to decNumber then to decimal128. */
268 real_to_decimal (string, from, sizeof (string), 0, 1);
269 decimal_real_from_string (to, string);
272 /* Helper function to real.c:do_compare() to handle decimal internal
273 representation including when one of the operands is still in the
274 binary internal representation. */
277 decimal_do_compare (const REAL_VALUE_TYPE *a, const REAL_VALUE_TYPE *b,
281 decNumber dn, dn2, dn3;
282 REAL_VALUE_TYPE a1, b1;
284 /* If either operand is non-decimal, create temporary versions. */
287 decimal_from_binary (&a1, a);
292 decimal_from_binary (&b1, b);
296 /* Convert into decNumber form for comparison operation. */
297 decContextDefault (&set, DEC_INIT_DECIMAL128);
299 decimal128ToNumber ((const decimal128 *) a->sig, &dn2);
300 decimal128ToNumber ((const decimal128 *) b->sig, &dn3);
302 /* Finally, do the comparison. */
303 decNumberCompare (&dn, &dn2, &dn3, &set);
305 /* Return the comparison result. */
306 if (decNumberIsNaN (&dn))
308 else if (decNumberIsZero (&dn))
310 else if (decNumberIsNegative (&dn))
316 /* Helper to round_for_format, handling decimal float types. */
319 decimal_round_for_format (const struct real_format *fmt, REAL_VALUE_TYPE *r)
324 /* Real encoding occurs later. */
325 if (r->cl != rvc_normal)
328 decContextDefault (&set, DEC_INIT_DECIMAL128);
330 decimal128ToNumber ((decimal128 *) r->sig, &dn);
332 if (fmt == &decimal_quad_format)
334 /* The internal format is already in this format. */
337 else if (fmt == &decimal_single_format)
340 decContextDefault (&set, DEC_INIT_DECIMAL32);
343 decimal32FromNumber (&d32, &dn, &set);
344 decimal32ToNumber (&d32, &dn);
346 else if (fmt == &decimal_double_format)
349 decContextDefault (&set, DEC_INIT_DECIMAL64);
352 decimal64FromNumber (&d64, &dn, &set);
353 decimal64ToNumber (&d64, &dn);
358 decimal_from_decnumber (r, &dn, &set);
361 /* Extend or truncate to a new mode. Handles conversions between
362 binary and decimal types. */
365 decimal_real_convert (REAL_VALUE_TYPE *r, enum machine_mode mode,
366 const REAL_VALUE_TYPE *a)
368 const struct real_format *fmt = REAL_MODE_FORMAT (mode);
370 if (a->decimal && fmt->b == 10)
373 decimal_to_binary (r, a, mode);
375 decimal_from_binary (r, a);
378 /* Render R_ORIG as a decimal floating point constant. Emit DIGITS
379 significant digits in the result, bounded by BUF_SIZE. If DIGITS
380 is 0, choose the maximum for the representation. If
381 CROP_TRAILING_ZEROS, strip trailing zeros. Currently, not honoring
382 DIGITS or CROP_TRAILING_ZEROS. */
385 decimal_real_to_decimal (char *str, const REAL_VALUE_TYPE *r_orig,
387 size_t digits ATTRIBUTE_UNUSED,
388 int crop_trailing_zeros ATTRIBUTE_UNUSED)
390 const decimal128 *const d128 = (const decimal128*) r_orig->sig;
392 /* decimal128ToString requires space for at least 24 characters;
393 Require two more for suffix. */
394 gcc_assert (buf_size >= 24);
395 decimal128ToString (d128, str);
399 decimal_do_add (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
400 const REAL_VALUE_TYPE *op1, int subtract_p)
406 decimal_to_decnumber (op0, &dn2);
407 decimal_to_decnumber (op1, &dn3);
409 decContextDefault (&set, DEC_INIT_DECIMAL128);
413 decNumberSubtract (&dn, &dn2, &dn3, &set);
415 decNumberAdd (&dn, &dn2, &dn3, &set);
417 decimal_from_decnumber (r, &dn, &set);
419 /* Return true, if inexact. */
420 return (set.status & DEC_Inexact);
423 /* Compute R = OP0 * OP1. */
426 decimal_do_multiply (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
427 const REAL_VALUE_TYPE *op1)
430 decNumber dn, dn2, dn3;
432 decimal_to_decnumber (op0, &dn2);
433 decimal_to_decnumber (op1, &dn3);
435 decContextDefault (&set, DEC_INIT_DECIMAL128);
438 decNumberMultiply (&dn, &dn2, &dn3, &set);
439 decimal_from_decnumber (r, &dn, &set);
441 /* Return true, if inexact. */
442 return (set.status & DEC_Inexact);
445 /* Compute R = OP0 / OP1. */
448 decimal_do_divide (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *op0,
449 const REAL_VALUE_TYPE *op1)
452 decNumber dn, dn2, dn3;
454 decimal_to_decnumber (op0, &dn2);
455 decimal_to_decnumber (op1, &dn3);
457 decContextDefault (&set, DEC_INIT_DECIMAL128);
460 decNumberDivide (&dn, &dn2, &dn3, &set);
461 decimal_from_decnumber (r, &dn, &set);
463 /* Return true, if inexact. */
464 return (set.status & DEC_Inexact);
467 /* Set R to A truncated to an integral value toward zero (decimal
471 decimal_do_fix_trunc (REAL_VALUE_TYPE *r, const REAL_VALUE_TYPE *a)
476 decContextDefault (&set, DEC_INIT_DECIMAL128);
478 set.round = DEC_ROUND_DOWN;
479 decimal128ToNumber ((const decimal128 *) a->sig, &dn2);
481 decNumberToIntegralValue (&dn, &dn2, &set);
482 decimal_from_decnumber (r, &dn, &set);
485 /* Render decimal float value R as an integer. */
488 decimal_real_to_integer (const REAL_VALUE_TYPE *r)
491 decNumber dn, dn2, dn3;
495 decContextDefault (&set, DEC_INIT_DECIMAL128);
497 set.round = DEC_ROUND_DOWN;
498 decimal128ToNumber ((const decimal128 *) r->sig, &dn);
500 decNumberToIntegralValue (&dn2, &dn, &set);
501 decNumberZero (&dn3);
502 decNumberRescale (&dn, &dn2, &dn3, &set);
504 /* Convert to REAL_VALUE_TYPE and call appropriate conversion
506 decNumberToString (&dn, string);
507 real_from_string (&to, string);
508 return real_to_integer (&to);
511 /* Likewise, but to an integer pair, HI+LOW. */
514 decimal_real_to_integer2 (HOST_WIDE_INT *plow, HOST_WIDE_INT *phigh,
515 const REAL_VALUE_TYPE *r)
518 decNumber dn, dn2, dn3;
522 decContextDefault (&set, DEC_INIT_DECIMAL128);
524 set.round = DEC_ROUND_DOWN;
525 decimal128ToNumber ((const decimal128 *) r->sig, &dn);
527 decNumberToIntegralValue (&dn2, &dn, &set);
528 decNumberZero (&dn3);
529 decNumberRescale (&dn, &dn2, &dn3, &set);
531 /* Convert to REAL_VALUE_TYPE and call appropriate conversion
533 decNumberToString (&dn, string);
534 real_from_string (&to, string);
535 real_to_integer2 (plow, phigh, &to);
538 /* Perform the decimal floating point operation described by CODE.
539 For a unary operation, OP1 will be NULL. This function returns
540 true if the result may be inexact due to loss of precision. */
543 decimal_real_arithmetic (REAL_VALUE_TYPE *r, enum tree_code code,
544 const REAL_VALUE_TYPE *op0,
545 const REAL_VALUE_TYPE *op1)
547 REAL_VALUE_TYPE a, b;
549 /* If either operand is non-decimal, create temporaries. */
552 decimal_from_binary (&a, op0);
555 if (op1 && !op1->decimal)
557 decimal_from_binary (&b, op1);
564 return decimal_do_add (r, op0, op1, 0);
567 return decimal_do_add (r, op0, op1, 1);
570 return decimal_do_multiply (r, op0, op1);
573 return decimal_do_divide (r, op0, op1);
576 if (op1->cl == rvc_nan)
578 else if (real_compare (UNLT_EXPR, op0, op1))
585 if (op1->cl == rvc_nan)
587 else if (real_compare (LT_EXPR, op0, op1))
597 decimal128FlipSign ((decimal128 *) r->sig);
598 /* Keep sign field in sync. */
606 /* Clear sign bit. */
607 decimal128ClearSign ((decimal128 *) r->sig);
608 /* Keep sign field in sync. */
614 decimal_do_fix_trunc (r, op0);
622 /* Fills R with the largest finite value representable in mode MODE.
623 If SIGN is nonzero, R is set to the most negative finite value. */
626 decimal_real_maxval (REAL_VALUE_TYPE *r, int sign, enum machine_mode mode)
636 max = "9.999999999999999E384";
639 max = "9.999999999999999999999999999999999E6144";
645 decimal_real_from_string (r, max);
647 decimal128SetSign ((decimal128 *) r->sig, 1);