1 ------------------------------------------------------------------------------
3 -- GNAT COMPILER COMPONENTS --
9 -- Copyright (C) 1992-2007, Free Software Foundation, Inc. --
11 -- GNAT is free software; you can redistribute it and/or modify it under --
12 -- terms of the GNU General Public License as published by the Free Soft- --
13 -- ware Foundation; either version 2, or (at your option) any later ver- --
14 -- sion. GNAT is distributed in the hope that it will be useful, but WITH- --
15 -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY --
16 -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License --
17 -- for more details. You should have received a copy of the GNU General --
18 -- Public License distributed with GNAT; see file COPYING. If not, write --
19 -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, --
20 -- Boston, MA 02110-1301, USA. --
22 -- As a special exception, if other files instantiate generics from this --
23 -- unit, or you link this unit with other files to produce an executable, --
24 -- this unit does not by itself cause the resulting executable to be --
25 -- covered by the GNU General Public License. This exception does not --
26 -- however invalidate any other reasons why the executable file might be --
27 -- covered by the GNU Public License. --
29 -- GNAT was originally developed by the GNAT team at New York University. --
30 -- Extensive contributions were provided by Ada Core Technologies Inc. --
32 ------------------------------------------------------------------------------
34 with Output; use Output;
35 with Tree_IO; use Tree_IO;
37 with GNAT.HTable; use GNAT.HTable;
41 ------------------------
42 -- Local Declarations --
43 ------------------------
45 Uint_Int_First : Uint := Uint_0;
46 -- Uint value containing Int'First value, set by Initialize. The initial
47 -- value of Uint_0 is used for an assertion check that ensures that this
48 -- value is not used before it is initialized. This value is used in the
49 -- UI_Is_In_Int_Range predicate, and it is right that this is a host value,
50 -- since the issue is host representation of integer values.
53 -- Uint value containing Int'Last value set by Initialize
55 UI_Power_2 : array (Int range 0 .. 64) of Uint;
56 -- This table is used to memoize exponentiations by powers of 2. The Nth
57 -- entry, if set, contains the Uint value 2 ** N. Initially UI_Power_2_Set
58 -- is zero and only the 0'th entry is set, the invariant being that all
59 -- entries in the range 0 .. UI_Power_2_Set are initialized.
62 -- Number of entries set in UI_Power_2;
64 UI_Power_10 : array (Int range 0 .. 64) of Uint;
65 -- This table is used to memoize exponentiations by powers of 10 in the
66 -- same manner as described above for UI_Power_2.
68 UI_Power_10_Set : Nat;
69 -- Number of entries set in UI_Power_10;
73 -- These values are used to make sure that the mark/release mechanism does
74 -- not destroy values saved in the U_Power tables or in the hash table used
75 -- by UI_From_Int. Whenever an entry is made in either of these tabls,
76 -- Uints_Min and Udigits_Min are updated to protect the entry, and Release
77 -- never cuts back beyond these minimum values.
79 Int_0 : constant Int := 0;
80 Int_1 : constant Int := 1;
81 Int_2 : constant Int := 2;
82 -- These values are used in some cases where the use of numeric literals
83 -- would cause ambiguities (integer vs Uint).
85 ----------------------------
86 -- UI_From_Int Hash Table --
87 ----------------------------
89 -- UI_From_Int uses a hash table to avoid duplicating entries and wasting
90 -- storage. This is particularly important for complex cases of back
93 subtype Hnum is Nat range 0 .. 1022;
95 function Hash_Num (F : Int) return Hnum;
98 package UI_Ints is new Simple_HTable (
101 No_Element => No_Uint,
106 -----------------------
107 -- Local Subprograms --
108 -----------------------
110 function Direct (U : Uint) return Boolean;
111 pragma Inline (Direct);
112 -- Returns True if U is represented directly
114 function Direct_Val (U : Uint) return Int;
115 -- U is a Uint for is represented directly. The returned result is the
116 -- value represented.
118 function GCD (Jin, Kin : Int) return Int;
119 -- Compute GCD of two integers. Assumes that Jin >= Kin >= 0
125 -- Common processing for UI_Image and UI_Write, To_Buffer is set True for
126 -- UI_Image, and false for UI_Write, and Format is copied from the Format
127 -- parameter to UI_Image or UI_Write.
129 procedure Init_Operand (UI : Uint; Vec : out UI_Vector);
130 pragma Inline (Init_Operand);
131 -- This procedure puts the value of UI into the vector in canonical
132 -- multiple precision format. The parameter should be of the correct size
133 -- as determined by a previous call to N_Digits (UI). The first digit of
134 -- Vec contains the sign, all other digits are always non- negative. Note
135 -- that the input may be directly represented, and in this case Vec will
136 -- contain the corresponding one or two digit value. The low bound of Vec
139 function Least_Sig_Digit (Arg : Uint) return Int;
140 pragma Inline (Least_Sig_Digit);
141 -- Returns the Least Significant Digit of Arg quickly. When the given Uint
142 -- is less than 2**15, the value returned is the input value, in this case
143 -- the result may be negative. It is expected that any use will mask off
144 -- unnecessary bits. This is used for finding Arg mod B where B is a power
145 -- of two. Hence the actual base is irrelevent as long as it is a power of
148 procedure Most_Sig_2_Digits
152 Right_Hat : out Int);
153 -- Returns leading two significant digits from the given pair of Uint's.
154 -- Mathematically: returns Left / (Base ** K) and Right / (Base ** K) where
155 -- K is as small as possible S.T. Right_Hat < Base * Base. It is required
156 -- that Left > Right for the algorithm to work.
158 function N_Digits (Input : Uint) return Int;
159 pragma Inline (N_Digits);
160 -- Returns number of "digits" in a Uint
162 function Sum_Digits (Left : Uint; Sign : Int) return Int;
163 -- If Sign = 1 return the sum of the "digits" of Abs (Left). If the total
164 -- has more then one digit then return Sum_Digits of total.
166 function Sum_Double_Digits (Left : Uint; Sign : Int) return Int;
167 -- Same as above but work in New_Base = Base * Base
172 Remainder : out Uint;
173 Discard_Quotient : Boolean;
174 Discard_Remainder : Boolean);
175 -- Compute euclidian division of Left by Right, and return Quotient and
176 -- signed Remainder (Left rem Right).
178 -- If Discard_Quotient is True, Quotient is left unchanged.
179 -- If Discard_Remainder is True, Remainder is left unchanged.
181 function Vector_To_Uint
183 Negative : Boolean) return Uint;
184 -- Functions that calculate values in UI_Vectors, call this function to
185 -- create and return the Uint value. In_Vec contains the multiple precision
186 -- (Base) representation of a non-negative value. Leading zeroes are
187 -- permitted. Negative is set if the desired result is the negative of the
188 -- given value. The result will be either the appropriate directly
189 -- represented value, or a table entry in the proper canonical format is
190 -- created and returned.
192 -- Note that Init_Operand puts a signed value in the result vector, but
193 -- Vector_To_Uint is always presented with a non-negative value. The
194 -- processing of signs is something that is done by the caller before
195 -- calling Vector_To_Uint.
201 function Direct (U : Uint) return Boolean is
203 return Int (U) <= Int (Uint_Direct_Last);
210 function Direct_Val (U : Uint) return Int is
212 pragma Assert (Direct (U));
213 return Int (U) - Int (Uint_Direct_Bias);
220 function GCD (Jin, Kin : Int) return Int is
224 pragma Assert (Jin >= Kin);
225 pragma Assert (Kin >= Int_0);
229 while K /= Uint_0 loop
242 function Hash_Num (F : Int) return Hnum is
244 return Standard."mod" (F, Hnum'Range_Length);
256 Marks : constant Uintp.Save_Mark := Uintp.Mark;
260 Digs_Output : Natural := 0;
261 -- Counts digits output. In hex mode, but not in decimal mode, we
262 -- put an underline after every four hex digits that are output.
264 Exponent : Natural := 0;
265 -- If the number is too long to fit in the buffer, we switch to an
266 -- approximate output format with an exponent. This variable records
267 -- the exponent value.
269 function Better_In_Hex return Boolean;
270 -- Determines if it is better to generate digits in base 16 (result
271 -- is true) or base 10 (result is false). The choice is purely a
272 -- matter of convenience and aesthetics, so it does not matter which
273 -- value is returned from a correctness point of view.
275 procedure Image_Char (C : Character);
276 -- Internal procedure to output one character
278 procedure Image_Exponent (N : Natural);
279 -- Output non-zero exponent. Note that we only use the exponent form in
280 -- the buffer case, so we know that To_Buffer is true.
282 procedure Image_Uint (U : Uint);
283 -- Internal procedure to output characters of non-negative Uint
289 function Better_In_Hex return Boolean is
290 T16 : constant Uint := Uint_2 ** Int'(16);
296 -- Small values up to 2**16 can always be in decimal
302 -- Otherwise, see if we are a power of 2 or one less than a power
303 -- of 2. For the moment these are the only cases printed in hex.
305 if A mod Uint_2 = Uint_1 then
310 if A mod T16 /= Uint_0 then
320 while A > Uint_2 loop
321 if A mod Uint_2 /= Uint_0 then
336 procedure Image_Char (C : Character) is
339 if UI_Image_Length + 6 > UI_Image_Max then
340 Exponent := Exponent + 1;
342 UI_Image_Length := UI_Image_Length + 1;
343 UI_Image_Buffer (UI_Image_Length) := C;
354 procedure Image_Exponent (N : Natural) is
357 Image_Exponent (N / 10);
360 UI_Image_Length := UI_Image_Length + 1;
361 UI_Image_Buffer (UI_Image_Length) :=
362 Character'Val (Character'Pos ('0') + N mod 10);
369 procedure Image_Uint (U : Uint) is
370 H : constant array (Int range 0 .. 15) of Character :=
375 Image_Uint (U / Base);
378 if Digs_Output = 4 and then Base = Uint_16 then
383 Image_Char (H (UI_To_Int (U rem Base)));
385 Digs_Output := Digs_Output + 1;
388 -- Start of processing for Image_Out
391 if Input = No_Uint then
396 UI_Image_Length := 0;
398 if Input < Uint_0 then
406 or else (Format = Auto and then Better_In_Hex)
420 if Exponent /= 0 then
421 UI_Image_Length := UI_Image_Length + 1;
422 UI_Image_Buffer (UI_Image_Length) := 'E';
423 Image_Exponent (Exponent);
426 Uintp.Release (Marks);
433 procedure Init_Operand (UI : Uint; Vec : out UI_Vector) is
436 pragma Assert (Vec'First = Int'(1));
440 Vec (1) := Direct_Val (UI);
442 if Vec (1) >= Base then
443 Vec (2) := Vec (1) rem Base;
444 Vec (1) := Vec (1) / Base;
448 Loc := Uints.Table (UI).Loc;
450 for J in 1 .. Uints.Table (UI).Length loop
451 Vec (J) := Udigits.Table (Loc + J - 1);
460 procedure Initialize is
465 Uint_Int_First := UI_From_Int (Int'First);
466 Uint_Int_Last := UI_From_Int (Int'Last);
468 UI_Power_2 (0) := Uint_1;
471 UI_Power_10 (0) := Uint_1;
472 UI_Power_10_Set := 0;
474 Uints_Min := Uints.Last;
475 Udigits_Min := Udigits.Last;
480 ---------------------
481 -- Least_Sig_Digit --
482 ---------------------
484 function Least_Sig_Digit (Arg : Uint) return Int is
489 V := Direct_Val (Arg);
495 -- Note that this result may be negative
502 (Uints.Table (Arg).Loc + Uints.Table (Arg).Length - 1);
510 function Mark return Save_Mark is
512 return (Save_Uint => Uints.Last, Save_Udigit => Udigits.Last);
515 -----------------------
516 -- Most_Sig_2_Digits --
517 -----------------------
519 procedure Most_Sig_2_Digits
526 pragma Assert (Left >= Right);
528 if Direct (Left) then
529 Left_Hat := Direct_Val (Left);
530 Right_Hat := Direct_Val (Right);
536 Udigits.Table (Uints.Table (Left).Loc);
538 Udigits.Table (Uints.Table (Left).Loc + 1);
541 -- It is not so clear what to return when Arg is negative???
543 Left_Hat := abs (L1) * Base + L2;
548 Length_L : constant Int := Uints.Table (Left).Length;
555 if Direct (Right) then
556 T := Direct_Val (Left);
557 R1 := abs (T / Base);
562 R1 := abs (Udigits.Table (Uints.Table (Right).Loc));
563 R2 := Udigits.Table (Uints.Table (Right).Loc + 1);
564 Length_R := Uints.Table (Right).Length;
567 if Length_L = Length_R then
568 Right_Hat := R1 * Base + R2;
569 elsif Length_L = Length_R + Int_1 then
575 end Most_Sig_2_Digits;
581 -- Note: N_Digits returns 1 for No_Uint
583 function N_Digits (Input : Uint) return Int is
585 if Direct (Input) then
586 if Direct_Val (Input) >= Base then
593 return Uints.Table (Input).Length;
601 function Num_Bits (Input : Uint) return Nat is
606 -- Largest negative number has to be handled specially, since it is in
607 -- Int_Range, but we cannot take the absolute value.
609 if Input = Uint_Int_First then
612 -- For any other number in Int_Range, get absolute value of number
614 elsif UI_Is_In_Int_Range (Input) then
615 Num := abs (UI_To_Int (Input));
618 -- If not in Int_Range then initialize bit count for all low order
619 -- words, and set number to high order digit.
622 Bits := Base_Bits * (Uints.Table (Input).Length - 1);
623 Num := abs (Udigits.Table (Uints.Table (Input).Loc));
626 -- Increase bit count for remaining value in Num
628 while Types.">" (Num, 0) loop
640 procedure pid (Input : Uint) is
642 UI_Write (Input, Decimal);
650 procedure pih (Input : Uint) is
652 UI_Write (Input, Hex);
660 procedure Release (M : Save_Mark) is
662 Uints.Set_Last (Uint'Max (M.Save_Uint, Uints_Min));
663 Udigits.Set_Last (Int'Max (M.Save_Udigit, Udigits_Min));
666 ----------------------
667 -- Release_And_Save --
668 ----------------------
670 procedure Release_And_Save (M : Save_Mark; UI : in out Uint) is
677 UE_Len : constant Pos := Uints.Table (UI).Length;
678 UE_Loc : constant Int := Uints.Table (UI).Loc;
680 UD : constant Udigits.Table_Type (1 .. UE_Len) :=
681 Udigits.Table (UE_Loc .. UE_Loc + UE_Len - 1);
686 Uints.Increment_Last;
689 Uints.Table (UI) := (UE_Len, Udigits.Last + 1);
691 for J in 1 .. UE_Len loop
692 Udigits.Increment_Last;
693 Udigits.Table (Udigits.Last) := UD (J);
697 end Release_And_Save;
699 procedure Release_And_Save (M : Save_Mark; UI1, UI2 : in out Uint) is
702 Release_And_Save (M, UI2);
704 elsif Direct (UI2) then
705 Release_And_Save (M, UI1);
709 UE1_Len : constant Pos := Uints.Table (UI1).Length;
710 UE1_Loc : constant Int := Uints.Table (UI1).Loc;
712 UD1 : constant Udigits.Table_Type (1 .. UE1_Len) :=
713 Udigits.Table (UE1_Loc .. UE1_Loc + UE1_Len - 1);
715 UE2_Len : constant Pos := Uints.Table (UI2).Length;
716 UE2_Loc : constant Int := Uints.Table (UI2).Loc;
718 UD2 : constant Udigits.Table_Type (1 .. UE2_Len) :=
719 Udigits.Table (UE2_Loc .. UE2_Loc + UE2_Len - 1);
724 Uints.Increment_Last;
727 Uints.Table (UI1) := (UE1_Len, Udigits.Last + 1);
729 for J in 1 .. UE1_Len loop
730 Udigits.Increment_Last;
731 Udigits.Table (Udigits.Last) := UD1 (J);
734 Uints.Increment_Last;
737 Uints.Table (UI2) := (UE2_Len, Udigits.Last + 1);
739 for J in 1 .. UE2_Len loop
740 Udigits.Increment_Last;
741 Udigits.Table (Udigits.Last) := UD2 (J);
745 end Release_And_Save;
751 -- This is done in one pass
753 -- Mathematically: assume base congruent to 1 and compute an equivelent
756 -- If Sign = -1 return the alternating sum of the "digits"
758 -- D1 - D2 + D3 - D4 + D5 ...
760 -- (where D1 is Least Significant Digit)
762 -- Mathematically: assume base congruent to -1 and compute an equivelent
765 -- This is used in Rem and Base is assumed to be 2 ** 15
767 -- Note: The next two functions are very similar, any style changes made
768 -- to one should be reflected in both. These would be simpler if we
769 -- worked base 2 ** 32.
771 function Sum_Digits (Left : Uint; Sign : Int) return Int is
773 pragma Assert (Sign = Int_1 or Sign = Int (-1));
775 -- First try simple case;
777 if Direct (Left) then
779 Tmp_Int : Int := Direct_Val (Left);
782 if Tmp_Int >= Base then
783 Tmp_Int := (Tmp_Int / Base) +
784 Sign * (Tmp_Int rem Base);
786 -- Now Tmp_Int is in [-(Base - 1) .. 2 * (Base - 1)]
788 if Tmp_Int >= Base then
792 Tmp_Int := (Tmp_Int / Base) + 1;
796 -- Now Tmp_Int is in [-(Base - 1) .. (Base - 1)]
803 -- Otherwise full circuit is needed
807 L_Length : constant Int := N_Digits (Left);
808 L_Vec : UI_Vector (1 .. L_Length);
814 Init_Operand (Left, L_Vec);
815 L_Vec (1) := abs L_Vec (1);
820 for J in reverse 1 .. L_Length loop
821 Tmp_Int := Tmp_Int + Alt * (L_Vec (J) + Carry);
823 -- Tmp_Int is now between [-2 * Base + 1 .. 2 * Base - 1],
824 -- since old Tmp_Int is between [-(Base - 1) .. Base - 1]
825 -- and L_Vec is in [0 .. Base - 1] and Carry in [-1 .. 1]
827 if Tmp_Int >= Base then
828 Tmp_Int := Tmp_Int - Base;
831 elsif Tmp_Int <= -Base then
832 Tmp_Int := Tmp_Int + Base;
839 -- Tmp_Int is now between [-Base + 1 .. Base - 1]
844 Tmp_Int := Tmp_Int + Alt * Carry;
846 -- Tmp_Int is now between [-Base .. Base]
848 if Tmp_Int >= Base then
849 Tmp_Int := Tmp_Int - Base + Alt * Sign * 1;
851 elsif Tmp_Int <= -Base then
852 Tmp_Int := Tmp_Int + Base + Alt * Sign * (-1);
855 -- Now Tmp_Int is in [-(Base - 1) .. (Base - 1)]
862 -----------------------
863 -- Sum_Double_Digits --
864 -----------------------
866 -- Note: This is used in Rem, Base is assumed to be 2 ** 15
868 function Sum_Double_Digits (Left : Uint; Sign : Int) return Int is
870 -- First try simple case;
872 pragma Assert (Sign = Int_1 or Sign = Int (-1));
874 if Direct (Left) then
875 return Direct_Val (Left);
877 -- Otherwise full circuit is needed
881 L_Length : constant Int := N_Digits (Left);
882 L_Vec : UI_Vector (1 .. L_Length);
890 Init_Operand (Left, L_Vec);
891 L_Vec (1) := abs L_Vec (1);
899 Least_Sig_Int := Least_Sig_Int + Alt * (L_Vec (J) + Carry);
901 -- Least is in [-2 Base + 1 .. 2 * Base - 1]
902 -- Since L_Vec in [0 .. Base - 1] and Carry in [-1 .. 1]
903 -- and old Least in [-Base + 1 .. Base - 1]
905 if Least_Sig_Int >= Base then
906 Least_Sig_Int := Least_Sig_Int - Base;
909 elsif Least_Sig_Int <= -Base then
910 Least_Sig_Int := Least_Sig_Int + Base;
917 -- Least is now in [-Base + 1 .. Base - 1]
919 Most_Sig_Int := Most_Sig_Int + Alt * (L_Vec (J - 1) + Carry);
921 -- Most is in [-2 Base + 1 .. 2 * Base - 1]
922 -- Since L_Vec in [0 .. Base - 1] and Carry in [-1 .. 1]
923 -- and old Most in [-Base + 1 .. Base - 1]
925 if Most_Sig_Int >= Base then
926 Most_Sig_Int := Most_Sig_Int - Base;
929 elsif Most_Sig_Int <= -Base then
930 Most_Sig_Int := Most_Sig_Int + Base;
936 -- Most is now in [-Base + 1 .. Base - 1]
943 Least_Sig_Int := Least_Sig_Int + Alt * (L_Vec (J) + Carry);
945 Least_Sig_Int := Least_Sig_Int + Alt * Carry;
948 if Least_Sig_Int >= Base then
949 Least_Sig_Int := Least_Sig_Int - Base;
950 Most_Sig_Int := Most_Sig_Int + Alt * 1;
952 elsif Least_Sig_Int <= -Base then
953 Least_Sig_Int := Least_Sig_Int + Base;
954 Most_Sig_Int := Most_Sig_Int + Alt * (-1);
957 if Most_Sig_Int >= Base then
958 Most_Sig_Int := Most_Sig_Int - Base;
961 Least_Sig_Int + Alt * 1; -- cannot overflow again
963 elsif Most_Sig_Int <= -Base then
964 Most_Sig_Int := Most_Sig_Int + Base;
967 Least_Sig_Int + Alt * (-1); -- cannot overflow again.
970 return Most_Sig_Int * Base + Least_Sig_Int;
973 end Sum_Double_Digits;
979 procedure Tree_Read is
984 Tree_Read_Int (Int (Uint_Int_First));
985 Tree_Read_Int (Int (Uint_Int_Last));
986 Tree_Read_Int (UI_Power_2_Set);
987 Tree_Read_Int (UI_Power_10_Set);
988 Tree_Read_Int (Int (Uints_Min));
989 Tree_Read_Int (Udigits_Min);
991 for J in 0 .. UI_Power_2_Set loop
992 Tree_Read_Int (Int (UI_Power_2 (J)));
995 for J in 0 .. UI_Power_10_Set loop
996 Tree_Read_Int (Int (UI_Power_10 (J)));
1005 procedure Tree_Write is
1010 Tree_Write_Int (Int (Uint_Int_First));
1011 Tree_Write_Int (Int (Uint_Int_Last));
1012 Tree_Write_Int (UI_Power_2_Set);
1013 Tree_Write_Int (UI_Power_10_Set);
1014 Tree_Write_Int (Int (Uints_Min));
1015 Tree_Write_Int (Udigits_Min);
1017 for J in 0 .. UI_Power_2_Set loop
1018 Tree_Write_Int (Int (UI_Power_2 (J)));
1021 for J in 0 .. UI_Power_10_Set loop
1022 Tree_Write_Int (Int (UI_Power_10 (J)));
1031 function UI_Abs (Right : Uint) return Uint is
1033 if Right < Uint_0 then
1044 function UI_Add (Left : Int; Right : Uint) return Uint is
1046 return UI_Add (UI_From_Int (Left), Right);
1049 function UI_Add (Left : Uint; Right : Int) return Uint is
1051 return UI_Add (Left, UI_From_Int (Right));
1054 function UI_Add (Left : Uint; Right : Uint) return Uint is
1056 -- Simple cases of direct operands and addition of zero
1058 if Direct (Left) then
1059 if Direct (Right) then
1060 return UI_From_Int (Direct_Val (Left) + Direct_Val (Right));
1062 elsif Int (Left) = Int (Uint_0) then
1066 elsif Direct (Right) and then Int (Right) = Int (Uint_0) then
1070 -- Otherwise full circuit is needed
1073 L_Length : constant Int := N_Digits (Left);
1074 R_Length : constant Int := N_Digits (Right);
1075 L_Vec : UI_Vector (1 .. L_Length);
1076 R_Vec : UI_Vector (1 .. R_Length);
1081 X_Bigger : Boolean := False;
1082 Y_Bigger : Boolean := False;
1083 Result_Neg : Boolean := False;
1086 Init_Operand (Left, L_Vec);
1087 Init_Operand (Right, R_Vec);
1089 -- At least one of the two operands is in multi-digit form.
1090 -- Calculate the number of digits sufficient to hold result.
1092 if L_Length > R_Length then
1093 Sum_Length := L_Length + 1;
1096 Sum_Length := R_Length + 1;
1098 if R_Length > L_Length then
1103 -- Make copies of the absolute values of L_Vec and R_Vec into X and Y
1104 -- both with lengths equal to the maximum possibly needed. This makes
1105 -- looping over the digits much simpler.
1108 X : UI_Vector (1 .. Sum_Length);
1109 Y : UI_Vector (1 .. Sum_Length);
1110 Tmp_UI : UI_Vector (1 .. Sum_Length);
1113 for J in 1 .. Sum_Length - L_Length loop
1117 X (Sum_Length - L_Length + 1) := abs L_Vec (1);
1119 for J in 2 .. L_Length loop
1120 X (J + (Sum_Length - L_Length)) := L_Vec (J);
1123 for J in 1 .. Sum_Length - R_Length loop
1127 Y (Sum_Length - R_Length + 1) := abs R_Vec (1);
1129 for J in 2 .. R_Length loop
1130 Y (J + (Sum_Length - R_Length)) := R_Vec (J);
1133 if (L_Vec (1) < Int_0) = (R_Vec (1) < Int_0) then
1135 -- Same sign so just add
1138 for J in reverse 1 .. Sum_Length loop
1139 Tmp_Int := X (J) + Y (J) + Carry;
1141 if Tmp_Int >= Base then
1142 Tmp_Int := Tmp_Int - Base;
1151 return Vector_To_Uint (X, L_Vec (1) < Int_0);
1154 -- Find which one has bigger magnitude
1156 if not (X_Bigger or Y_Bigger) then
1157 for J in L_Vec'Range loop
1158 if abs L_Vec (J) > abs R_Vec (J) then
1161 elsif abs R_Vec (J) > abs L_Vec (J) then
1168 -- If they have identical magnitude, just return 0, else swap
1169 -- if necessary so that X had the bigger magnitude. Determine
1170 -- if result is negative at this time.
1172 Result_Neg := False;
1174 if not (X_Bigger or Y_Bigger) then
1178 if R_Vec (1) < Int_0 then
1187 if L_Vec (1) < Int_0 then
1192 -- Subtract Y from the bigger X
1196 for J in reverse 1 .. Sum_Length loop
1197 Tmp_Int := X (J) - Y (J) + Borrow;
1199 if Tmp_Int < Int_0 then
1200 Tmp_Int := Tmp_Int + Base;
1209 return Vector_To_Uint (X, Result_Neg);
1216 --------------------------
1217 -- UI_Decimal_Digits_Hi --
1218 --------------------------
1220 function UI_Decimal_Digits_Hi (U : Uint) return Nat is
1222 -- The maximum value of a "digit" is 32767, which is 5 decimal digits,
1223 -- so an N_Digit number could take up to 5 times this number of digits.
1224 -- This is certainly too high for large numbers but it is not worth
1227 return 5 * N_Digits (U);
1228 end UI_Decimal_Digits_Hi;
1230 --------------------------
1231 -- UI_Decimal_Digits_Lo --
1232 --------------------------
1234 function UI_Decimal_Digits_Lo (U : Uint) return Nat is
1236 -- The maximum value of a "digit" is 32767, which is more than four
1237 -- decimal digits, but not a full five digits. The easily computed
1238 -- minimum number of decimal digits is thus 1 + 4 * the number of
1239 -- digits. This is certainly too low for large numbers but it is not
1240 -- worth worrying about.
1242 return 1 + 4 * (N_Digits (U) - 1);
1243 end UI_Decimal_Digits_Lo;
1249 function UI_Div (Left : Int; Right : Uint) return Uint is
1251 return UI_Div (UI_From_Int (Left), Right);
1254 function UI_Div (Left : Uint; Right : Int) return Uint is
1256 return UI_Div (Left, UI_From_Int (Right));
1259 function UI_Div (Left, Right : Uint) return Uint is
1262 pragma Warnings (Off, Remainder);
1266 Quotient, Remainder,
1267 Discard_Quotient => False,
1268 Discard_Remainder => True);
1276 procedure UI_Div_Rem
1277 (Left, Right : Uint;
1278 Quotient : out Uint;
1279 Remainder : out Uint;
1280 Discard_Quotient : Boolean;
1281 Discard_Remainder : Boolean)
1284 pragma Assert (Right /= Uint_0);
1286 -- Cases where both operands are represented directly
1288 if Direct (Left) and then Direct (Right) then
1290 DV_Left : constant Int := Direct_Val (Left);
1291 DV_Right : constant Int := Direct_Val (Right);
1294 if not Discard_Quotient then
1295 Quotient := UI_From_Int (DV_Left / DV_Right);
1298 if not Discard_Remainder then
1299 Remainder := UI_From_Int (DV_Left rem DV_Right);
1307 L_Length : constant Int := N_Digits (Left);
1308 R_Length : constant Int := N_Digits (Right);
1309 Q_Length : constant Int := L_Length - R_Length + 1;
1310 L_Vec : UI_Vector (1 .. L_Length);
1311 R_Vec : UI_Vector (1 .. R_Length);
1319 procedure UI_Div_Vector
1322 Quotient : out UI_Vector;
1323 Remainder : out Int);
1324 pragma Inline (UI_Div_Vector);
1325 -- Specialised variant for case where the divisor is a single digit
1327 procedure UI_Div_Vector
1330 Quotient : out UI_Vector;
1331 Remainder : out Int)
1337 for J in L_Vec'Range loop
1338 Tmp_Int := Remainder * Base + abs L_Vec (J);
1339 Quotient (Quotient'First + J - L_Vec'First) := Tmp_Int / R_Int;
1340 Remainder := Tmp_Int rem R_Int;
1343 if L_Vec (L_Vec'First) < Int_0 then
1344 Remainder := -Remainder;
1348 -- Start of processing for UI_Div_Rem
1351 -- Result is zero if left operand is shorter than right
1353 if L_Length < R_Length then
1354 if not Discard_Quotient then
1357 if not Discard_Remainder then
1363 Init_Operand (Left, L_Vec);
1364 Init_Operand (Right, R_Vec);
1366 -- Case of right operand is single digit. Here we can simply divide
1367 -- each digit of the left operand by the divisor, from most to least
1368 -- significant, carrying the remainder to the next digit (just like
1369 -- ordinary long division by hand).
1371 if R_Length = Int_1 then
1372 Tmp_Divisor := abs R_Vec (1);
1375 Quotient_V : UI_Vector (1 .. L_Length);
1378 UI_Div_Vector (L_Vec, Tmp_Divisor, Quotient_V, Remainder_I);
1380 if not Discard_Quotient then
1383 (Quotient_V, (L_Vec (1) < Int_0 xor R_Vec (1) < Int_0));
1386 if not Discard_Remainder then
1387 Remainder := UI_From_Int (Remainder_I);
1393 -- The possible simple cases have been exhausted. Now turn to the
1394 -- algorithm D from the section of Knuth mentioned at the top of
1397 Algorithm_D : declare
1398 Dividend : UI_Vector (1 .. L_Length + 1);
1399 Divisor : UI_Vector (1 .. R_Length);
1400 Quotient_V : UI_Vector (1 .. Q_Length);
1406 -- [ NORMALIZE ] (step D1 in the algorithm). First calculate the
1407 -- scale d, and then multiply Left and Right (u and v in the book)
1408 -- by d to get the dividend and divisor to work with.
1410 D := Base / (abs R_Vec (1) + 1);
1413 Dividend (2) := abs L_Vec (1);
1415 for J in 3 .. L_Length + Int_1 loop
1416 Dividend (J) := L_Vec (J - 1);
1419 Divisor (1) := abs R_Vec (1);
1421 for J in Int_2 .. R_Length loop
1422 Divisor (J) := R_Vec (J);
1427 -- Multiply Dividend by D
1430 for J in reverse Dividend'Range loop
1431 Tmp_Int := Dividend (J) * D + Carry;
1432 Dividend (J) := Tmp_Int rem Base;
1433 Carry := Tmp_Int / Base;
1436 -- Multiply Divisor by d
1439 for J in reverse Divisor'Range loop
1440 Tmp_Int := Divisor (J) * D + Carry;
1441 Divisor (J) := Tmp_Int rem Base;
1442 Carry := Tmp_Int / Base;
1446 -- Main loop of long division algorithm
1448 Divisor_Dig1 := Divisor (1);
1449 Divisor_Dig2 := Divisor (2);
1451 for J in Quotient_V'Range loop
1453 -- [ CALCULATE Q (hat) ] (step D3 in the algorithm)
1455 Tmp_Int := Dividend (J) * Base + Dividend (J + 1);
1459 if Dividend (J) = Divisor_Dig1 then
1460 Q_Guess := Base - 1;
1462 Q_Guess := Tmp_Int / Divisor_Dig1;
1467 while Divisor_Dig2 * Q_Guess >
1468 (Tmp_Int - Q_Guess * Divisor_Dig1) * Base +
1471 Q_Guess := Q_Guess - 1;
1474 -- [ MULTIPLY & SUBTRACT ] (step D4). Q_Guess * Divisor is
1475 -- subtracted from the remaining dividend.
1478 for K in reverse Divisor'Range loop
1479 Tmp_Int := Dividend (J + K) - Q_Guess * Divisor (K) + Carry;
1480 Tmp_Dig := Tmp_Int rem Base;
1481 Carry := Tmp_Int / Base;
1483 if Tmp_Dig < Int_0 then
1484 Tmp_Dig := Tmp_Dig + Base;
1488 Dividend (J + K) := Tmp_Dig;
1491 Dividend (J) := Dividend (J) + Carry;
1493 -- [ TEST REMAINDER ] & [ ADD BACK ] (steps D5 and D6)
1495 -- Here there is a slight difference from the book: the last
1496 -- carry is always added in above and below (cancelling each
1497 -- other). In fact the dividend going negative is used as
1500 -- If the Dividend went negative, then Q_Guess was off by
1501 -- one, so it is decremented, and the divisor is added back
1502 -- into the relevant portion of the dividend.
1504 if Dividend (J) < Int_0 then
1505 Q_Guess := Q_Guess - 1;
1508 for K in reverse Divisor'Range loop
1509 Tmp_Int := Dividend (J + K) + Divisor (K) + Carry;
1511 if Tmp_Int >= Base then
1512 Tmp_Int := Tmp_Int - Base;
1518 Dividend (J + K) := Tmp_Int;
1521 Dividend (J) := Dividend (J) + Carry;
1524 -- Finally we can get the next quotient digit
1526 Quotient_V (J) := Q_Guess;
1529 -- [ UNNORMALIZE ] (step D8)
1531 if not Discard_Quotient then
1532 Quotient := Vector_To_Uint
1533 (Quotient_V, (L_Vec (1) < Int_0 xor R_Vec (1) < Int_0));
1536 if not Discard_Remainder then
1538 Remainder_V : UI_Vector (1 .. R_Length);
1540 pragma Warnings (Off, Discard_Int);
1543 (Dividend (Dividend'Last - R_Length + 1 .. Dividend'Last),
1545 Remainder_V, Discard_Int);
1546 Remainder := Vector_To_Uint (Remainder_V, L_Vec (1) < Int_0);
1557 function UI_Eq (Left : Int; Right : Uint) return Boolean is
1559 return not UI_Ne (UI_From_Int (Left), Right);
1562 function UI_Eq (Left : Uint; Right : Int) return Boolean is
1564 return not UI_Ne (Left, UI_From_Int (Right));
1567 function UI_Eq (Left : Uint; Right : Uint) return Boolean is
1569 return not UI_Ne (Left, Right);
1576 function UI_Expon (Left : Int; Right : Uint) return Uint is
1578 return UI_Expon (UI_From_Int (Left), Right);
1581 function UI_Expon (Left : Uint; Right : Int) return Uint is
1583 return UI_Expon (Left, UI_From_Int (Right));
1586 function UI_Expon (Left : Int; Right : Int) return Uint is
1588 return UI_Expon (UI_From_Int (Left), UI_From_Int (Right));
1591 function UI_Expon (Left : Uint; Right : Uint) return Uint is
1593 pragma Assert (Right >= Uint_0);
1595 -- Any value raised to power of 0 is 1
1597 if Right = Uint_0 then
1600 -- 0 to any positive power is 0
1602 elsif Left = Uint_0 then
1605 -- 1 to any power is 1
1607 elsif Left = Uint_1 then
1610 -- Any value raised to power of 1 is that value
1612 elsif Right = Uint_1 then
1615 -- Cases which can be done by table lookup
1617 elsif Right <= Uint_64 then
1619 -- 2 ** N for N in 2 .. 64
1621 if Left = Uint_2 then
1623 Right_Int : constant Int := Direct_Val (Right);
1626 if Right_Int > UI_Power_2_Set then
1627 for J in UI_Power_2_Set + Int_1 .. Right_Int loop
1628 UI_Power_2 (J) := UI_Power_2 (J - Int_1) * Int_2;
1629 Uints_Min := Uints.Last;
1630 Udigits_Min := Udigits.Last;
1633 UI_Power_2_Set := Right_Int;
1636 return UI_Power_2 (Right_Int);
1639 -- 10 ** N for N in 2 .. 64
1641 elsif Left = Uint_10 then
1643 Right_Int : constant Int := Direct_Val (Right);
1646 if Right_Int > UI_Power_10_Set then
1647 for J in UI_Power_10_Set + Int_1 .. Right_Int loop
1648 UI_Power_10 (J) := UI_Power_10 (J - Int_1) * Int (10);
1649 Uints_Min := Uints.Last;
1650 Udigits_Min := Udigits.Last;
1653 UI_Power_10_Set := Right_Int;
1656 return UI_Power_10 (Right_Int);
1661 -- If we fall through, then we have the general case (see Knuth 4.6.3)
1665 Squares : Uint := Left;
1666 Result : Uint := Uint_1;
1667 M : constant Uintp.Save_Mark := Uintp.Mark;
1671 if (Least_Sig_Digit (N) mod Int_2) = Int_1 then
1672 Result := Result * Squares;
1676 exit when N = Uint_0;
1677 Squares := Squares * Squares;
1680 Uintp.Release_And_Save (M, Result);
1689 function UI_From_CC (Input : Char_Code) return Uint is
1691 return UI_From_Dint (Dint (Input));
1698 function UI_From_Dint (Input : Dint) return Uint is
1701 if Dint (Min_Direct) <= Input and then Input <= Dint (Max_Direct) then
1702 return Uint (Dint (Uint_Direct_Bias) + Input);
1704 -- For values of larger magnitude, compute digits into a vector and call
1709 Max_For_Dint : constant := 5;
1710 -- Base is defined so that 5 Uint digits is sufficient to hold the
1711 -- largest possible Dint value.
1713 V : UI_Vector (1 .. Max_For_Dint);
1715 Temp_Integer : Dint;
1718 for J in V'Range loop
1722 Temp_Integer := Input;
1724 for J in reverse V'Range loop
1725 V (J) := Int (abs (Temp_Integer rem Dint (Base)));
1726 Temp_Integer := Temp_Integer / Dint (Base);
1729 return Vector_To_Uint (V, Input < Dint'(0));
1738 function UI_From_Int (Input : Int) return Uint is
1742 if Min_Direct <= Input and then Input <= Max_Direct then
1743 return Uint (Int (Uint_Direct_Bias) + Input);
1746 -- If already in the hash table, return entry
1748 U := UI_Ints.Get (Input);
1750 if U /= No_Uint then
1754 -- For values of larger magnitude, compute digits into a vector and call
1758 Max_For_Int : constant := 3;
1759 -- Base is defined so that 3 Uint digits is sufficient to hold the
1760 -- largest possible Int value.
1762 V : UI_Vector (1 .. Max_For_Int);
1767 for J in V'Range loop
1771 Temp_Integer := Input;
1773 for J in reverse V'Range loop
1774 V (J) := abs (Temp_Integer rem Base);
1775 Temp_Integer := Temp_Integer / Base;
1778 U := Vector_To_Uint (V, Input < Int_0);
1779 UI_Ints.Set (Input, U);
1780 Uints_Min := Uints.Last;
1781 Udigits_Min := Udigits.Last;
1790 -- Lehmer's algorithm for GCD
1792 -- The idea is to avoid using multiple precision arithmetic wherever
1793 -- possible, substituting Int arithmetic instead. See Knuth volume II,
1794 -- Algorithm L (page 329).
1796 -- We use the same notation as Knuth (U_Hat standing for the obvious!)
1798 function UI_GCD (Uin, Vin : Uint) return Uint is
1800 -- Copies of Uin and Vin
1803 -- The most Significant digits of U,V
1805 A, B, C, D, T, Q, Den1, Den2 : Int;
1808 Marks : constant Uintp.Save_Mark := Uintp.Mark;
1809 Iterations : Integer := 0;
1812 pragma Assert (Uin >= Vin);
1813 pragma Assert (Vin >= Uint_0);
1819 Iterations := Iterations + 1;
1826 UI_From_Int (GCD (Direct_Val (V), UI_To_Int (U rem V)));
1830 Most_Sig_2_Digits (U, V, U_Hat, V_Hat);
1837 -- We might overflow and get division by zero here. This just
1838 -- means we cannot take the single precision step
1842 exit when (Den1 * Den2) = Int_0;
1844 -- Compute Q, the trial quotient
1846 Q := (U_Hat + A) / Den1;
1848 exit when Q /= ((U_Hat + B) / Den2);
1850 -- A single precision step Euclid step will give same answer as a
1851 -- multiprecision one.
1861 T := U_Hat - (Q * V_Hat);
1867 -- Take a multiprecision Euclid step
1871 -- No single precision steps take a regular Euclid step
1878 -- Use prior single precision steps to compute this Euclid step
1880 -- For constructs such as:
1881 -- sqrt_2: constant := 1.41421_35623_73095_04880_16887_24209_698;
1882 -- sqrt_eps: constant long_float := long_float( 1.0 / sqrt_2)
1883 -- ** long_float'machine_mantissa;
1885 -- we spend 80% of our time working on this step. Perhaps we need
1886 -- a special case Int / Uint dot product to speed things up. ???
1888 -- Alternatively we could increase the single precision iterations
1889 -- to handle Uint's of some small size ( <5 digits?). Then we
1890 -- would have more iterations on small Uint. On the code above, we
1891 -- only get 5 (on average) single precision iterations per large
1894 Tmp_UI := (UI_From_Int (A) * U) + (UI_From_Int (B) * V);
1895 V := (UI_From_Int (C) * U) + (UI_From_Int (D) * V);
1899 -- If the operands are very different in magnitude, the loop will
1900 -- generate large amounts of short-lived data, which it is worth
1901 -- removing periodically.
1903 if Iterations > 100 then
1904 Release_And_Save (Marks, U, V);
1914 function UI_Ge (Left : Int; Right : Uint) return Boolean is
1916 return not UI_Lt (UI_From_Int (Left), Right);
1919 function UI_Ge (Left : Uint; Right : Int) return Boolean is
1921 return not UI_Lt (Left, UI_From_Int (Right));
1924 function UI_Ge (Left : Uint; Right : Uint) return Boolean is
1926 return not UI_Lt (Left, Right);
1933 function UI_Gt (Left : Int; Right : Uint) return Boolean is
1935 return UI_Lt (Right, UI_From_Int (Left));
1938 function UI_Gt (Left : Uint; Right : Int) return Boolean is
1940 return UI_Lt (UI_From_Int (Right), Left);
1943 function UI_Gt (Left : Uint; Right : Uint) return Boolean is
1945 return UI_Lt (Right, Left);
1952 procedure UI_Image (Input : Uint; Format : UI_Format := Auto) is
1954 Image_Out (Input, True, Format);
1957 -------------------------
1958 -- UI_Is_In_Int_Range --
1959 -------------------------
1961 function UI_Is_In_Int_Range (Input : Uint) return Boolean is
1963 -- Make sure we don't get called before Initialize
1965 pragma Assert (Uint_Int_First /= Uint_0);
1967 if Direct (Input) then
1970 return Input >= Uint_Int_First
1971 and then Input <= Uint_Int_Last;
1973 end UI_Is_In_Int_Range;
1979 function UI_Le (Left : Int; Right : Uint) return Boolean is
1981 return not UI_Lt (Right, UI_From_Int (Left));
1984 function UI_Le (Left : Uint; Right : Int) return Boolean is
1986 return not UI_Lt (UI_From_Int (Right), Left);
1989 function UI_Le (Left : Uint; Right : Uint) return Boolean is
1991 return not UI_Lt (Right, Left);
1998 function UI_Lt (Left : Int; Right : Uint) return Boolean is
2000 return UI_Lt (UI_From_Int (Left), Right);
2003 function UI_Lt (Left : Uint; Right : Int) return Boolean is
2005 return UI_Lt (Left, UI_From_Int (Right));
2008 function UI_Lt (Left : Uint; Right : Uint) return Boolean is
2010 -- Quick processing for identical arguments
2012 if Int (Left) = Int (Right) then
2015 -- Quick processing for both arguments directly represented
2017 elsif Direct (Left) and then Direct (Right) then
2018 return Int (Left) < Int (Right);
2020 -- At least one argument is more than one digit long
2024 L_Length : constant Int := N_Digits (Left);
2025 R_Length : constant Int := N_Digits (Right);
2027 L_Vec : UI_Vector (1 .. L_Length);
2028 R_Vec : UI_Vector (1 .. R_Length);
2031 Init_Operand (Left, L_Vec);
2032 Init_Operand (Right, R_Vec);
2034 if L_Vec (1) < Int_0 then
2036 -- First argument negative, second argument non-negative
2038 if R_Vec (1) >= Int_0 then
2041 -- Both arguments negative
2044 if L_Length /= R_Length then
2045 return L_Length > R_Length;
2047 elsif L_Vec (1) /= R_Vec (1) then
2048 return L_Vec (1) < R_Vec (1);
2051 for J in 2 .. L_Vec'Last loop
2052 if L_Vec (J) /= R_Vec (J) then
2053 return L_Vec (J) > R_Vec (J);
2062 -- First argument non-negative, second argument negative
2064 if R_Vec (1) < Int_0 then
2067 -- Both arguments non-negative
2070 if L_Length /= R_Length then
2071 return L_Length < R_Length;
2073 for J in L_Vec'Range loop
2074 if L_Vec (J) /= R_Vec (J) then
2075 return L_Vec (J) < R_Vec (J);
2091 function UI_Max (Left : Int; Right : Uint) return Uint is
2093 return UI_Max (UI_From_Int (Left), Right);
2096 function UI_Max (Left : Uint; Right : Int) return Uint is
2098 return UI_Max (Left, UI_From_Int (Right));
2101 function UI_Max (Left : Uint; Right : Uint) return Uint is
2103 if Left >= Right then
2114 function UI_Min (Left : Int; Right : Uint) return Uint is
2116 return UI_Min (UI_From_Int (Left), Right);
2119 function UI_Min (Left : Uint; Right : Int) return Uint is
2121 return UI_Min (Left, UI_From_Int (Right));
2124 function UI_Min (Left : Uint; Right : Uint) return Uint is
2126 if Left <= Right then
2137 function UI_Mod (Left : Int; Right : Uint) return Uint is
2139 return UI_Mod (UI_From_Int (Left), Right);
2142 function UI_Mod (Left : Uint; Right : Int) return Uint is
2144 return UI_Mod (Left, UI_From_Int (Right));
2147 function UI_Mod (Left : Uint; Right : Uint) return Uint is
2148 Urem : constant Uint := Left rem Right;
2151 if (Left < Uint_0) = (Right < Uint_0)
2152 or else Urem = Uint_0
2156 return Right + Urem;
2160 -------------------------------
2161 -- UI_Modular_Exponentiation --
2162 -------------------------------
2164 function UI_Modular_Exponentiation
2167 Modulo : Uint) return Uint
2169 M : constant Save_Mark := Mark;
2171 Result : Uint := Uint_1;
2173 Exponent : Uint := E;
2176 while Exponent /= Uint_0 loop
2177 if Least_Sig_Digit (Exponent) rem Int'(2) = Int'(1) then
2178 Result := (Result * Base) rem Modulo;
2181 Exponent := Exponent / Uint_2;
2182 Base := (Base * Base) rem Modulo;
2185 Release_And_Save (M, Result);
2187 end UI_Modular_Exponentiation;
2189 ------------------------
2190 -- UI_Modular_Inverse --
2191 ------------------------
2193 function UI_Modular_Inverse (N : Uint; Modulo : Uint) return Uint is
2194 M : constant Save_Mark := Mark;
2214 Quotient => Q, Remainder => R,
2215 Discard_Quotient => False,
2216 Discard_Remainder => False);
2226 exit when R = Uint_1;
2229 if S = Int'(-1) then
2233 Release_And_Save (M, X);
2235 end UI_Modular_Inverse;
2241 function UI_Mul (Left : Int; Right : Uint) return Uint is
2243 return UI_Mul (UI_From_Int (Left), Right);
2246 function UI_Mul (Left : Uint; Right : Int) return Uint is
2248 return UI_Mul (Left, UI_From_Int (Right));
2251 function UI_Mul (Left : Uint; Right : Uint) return Uint is
2253 -- Simple case of single length operands
2255 if Direct (Left) and then Direct (Right) then
2258 (Dint (Direct_Val (Left)) * Dint (Direct_Val (Right)));
2261 -- Otherwise we have the general case (Algorithm M in Knuth)
2264 L_Length : constant Int := N_Digits (Left);
2265 R_Length : constant Int := N_Digits (Right);
2266 L_Vec : UI_Vector (1 .. L_Length);
2267 R_Vec : UI_Vector (1 .. R_Length);
2271 Init_Operand (Left, L_Vec);
2272 Init_Operand (Right, R_Vec);
2273 Neg := (L_Vec (1) < Int_0) xor (R_Vec (1) < Int_0);
2274 L_Vec (1) := abs (L_Vec (1));
2275 R_Vec (1) := abs (R_Vec (1));
2277 Algorithm_M : declare
2278 Product : UI_Vector (1 .. L_Length + R_Length);
2283 for J in Product'Range loop
2287 for J in reverse R_Vec'Range loop
2289 for K in reverse L_Vec'Range loop
2291 L_Vec (K) * R_Vec (J) + Product (J + K) + Carry;
2292 Product (J + K) := Tmp_Sum rem Base;
2293 Carry := Tmp_Sum / Base;
2296 Product (J) := Carry;
2299 return Vector_To_Uint (Product, Neg);
2308 function UI_Ne (Left : Int; Right : Uint) return Boolean is
2310 return UI_Ne (UI_From_Int (Left), Right);
2313 function UI_Ne (Left : Uint; Right : Int) return Boolean is
2315 return UI_Ne (Left, UI_From_Int (Right));
2318 function UI_Ne (Left : Uint; Right : Uint) return Boolean is
2320 -- Quick processing for identical arguments. Note that this takes
2321 -- care of the case of two No_Uint arguments.
2323 if Int (Left) = Int (Right) then
2327 -- See if left operand directly represented
2329 if Direct (Left) then
2331 -- If right operand directly represented then compare
2333 if Direct (Right) then
2334 return Int (Left) /= Int (Right);
2336 -- Left operand directly represented, right not, must be unequal
2342 -- Right operand directly represented, left not, must be unequal
2344 elsif Direct (Right) then
2348 -- Otherwise both multi-word, do comparison
2351 Size : constant Int := N_Digits (Left);
2356 if Size /= N_Digits (Right) then
2360 Left_Loc := Uints.Table (Left).Loc;
2361 Right_Loc := Uints.Table (Right).Loc;
2363 for J in Int_0 .. Size - Int_1 loop
2364 if Udigits.Table (Left_Loc + J) /=
2365 Udigits.Table (Right_Loc + J)
2379 function UI_Negate (Right : Uint) return Uint is
2381 -- Case where input is directly represented. Note that since the range
2382 -- of Direct values is non-symmetrical, the result may not be directly
2383 -- represented, this is taken care of in UI_From_Int.
2385 if Direct (Right) then
2386 return UI_From_Int (-Direct_Val (Right));
2388 -- Full processing for multi-digit case. Note that we cannot just copy
2389 -- the value to the end of the table negating the first digit, since the
2390 -- range of Direct values is non-symmetrical, so we can have a negative
2391 -- value that is not Direct whose negation can be represented directly.
2395 R_Length : constant Int := N_Digits (Right);
2396 R_Vec : UI_Vector (1 .. R_Length);
2400 Init_Operand (Right, R_Vec);
2401 Neg := R_Vec (1) > Int_0;
2402 R_Vec (1) := abs R_Vec (1);
2403 return Vector_To_Uint (R_Vec, Neg);
2412 function UI_Rem (Left : Int; Right : Uint) return Uint is
2414 return UI_Rem (UI_From_Int (Left), Right);
2417 function UI_Rem (Left : Uint; Right : Int) return Uint is
2419 return UI_Rem (Left, UI_From_Int (Right));
2422 function UI_Rem (Left, Right : Uint) return Uint is
2426 subtype Int1_12 is Integer range 1 .. 12;
2429 pragma Assert (Right /= Uint_0);
2431 if Direct (Right) then
2432 if Direct (Left) then
2433 return UI_From_Int (Direct_Val (Left) rem Direct_Val (Right));
2437 -- Special cases when Right is less than 13 and Left is larger
2438 -- larger than one digit. All of these algorithms depend on the
2439 -- base being 2 ** 15 We work with Abs (Left) and Abs(Right)
2440 -- then multiply result by Sign (Left)
2442 if (Right <= Uint_12) and then (Right >= Uint_Minus_12) then
2444 if Left < Uint_0 then
2450 -- All cases are listed, grouped by mathematical method It is
2451 -- not inefficient to do have this case list out of order since
2452 -- GCC sorts the cases we list.
2454 case Int1_12 (abs (Direct_Val (Right))) is
2459 -- Powers of two are simple AND's with LS Left Digit GCC
2460 -- will recognise these constants as powers of 2 and replace
2461 -- the rem with simpler operations where possible.
2463 -- Least_Sig_Digit might return Negative numbers
2466 return UI_From_Int (
2467 Sign * (Least_Sig_Digit (Left) mod 2));
2470 return UI_From_Int (
2471 Sign * (Least_Sig_Digit (Left) mod 4));
2474 return UI_From_Int (
2475 Sign * (Least_Sig_Digit (Left) mod 8));
2477 -- Some number theoretical tricks:
2479 -- If B Rem Right = 1 then
2480 -- Left Rem Right = Sum_Of_Digits_Base_B (Left) Rem Right
2482 -- Note: 2^32 mod 3 = 1
2485 return UI_From_Int (
2486 Sign * (Sum_Double_Digits (Left, 1) rem Int (3)));
2488 -- Note: 2^15 mod 7 = 1
2491 return UI_From_Int (
2492 Sign * (Sum_Digits (Left, 1) rem Int (7)));
2494 -- Note: 2^32 mod 5 = -1
2496 -- Alternating sums might be negative, but rem is always
2497 -- positive hence we must use mod here.
2500 Tmp := Sum_Double_Digits (Left, -1) mod Int (5);
2501 return UI_From_Int (Sign * Tmp);
2503 -- Note: 2^15 mod 9 = -1
2505 -- Alternating sums might be negative, but rem is always
2506 -- positive hence we must use mod here.
2509 Tmp := Sum_Digits (Left, -1) mod Int (9);
2510 return UI_From_Int (Sign * Tmp);
2512 -- Note: 2^15 mod 11 = -1
2514 -- Alternating sums might be negative, but rem is always
2515 -- positive hence we must use mod here.
2518 Tmp := Sum_Digits (Left, -1) mod Int (11);
2519 return UI_From_Int (Sign * Tmp);
2521 -- Now resort to Chinese Remainder theorem to reduce 6, 10,
2522 -- 12 to previous special cases
2524 -- There is no reason we could not add more cases like these
2525 -- if it proves useful.
2527 -- Perhaps we should go up to 16, however we have no "trick"
2530 -- To find u mod m we:
2533 -- GCD(m1, m2) = 1 AND m = (m1 * m2).
2535 -- Next we pick (Basis) M1, M2 small S.T.
2536 -- (M1 mod m1) = (M2 mod m2) = 1 AND
2537 -- (M1 mod m2) = (M2 mod m1) = 0
2539 -- So u mod m = (u1 * M1 + u2 * M2) mod m Where u1 = (u mod
2540 -- m1) AND u2 = (u mod m2); Under typical circumstances the
2541 -- last mod m can be done with a (possible) single
2544 -- m1 = 2; m2 = 3; M1 = 3; M2 = 4;
2547 Tmp := 3 * (Least_Sig_Digit (Left) rem 2) +
2548 4 * (Sum_Double_Digits (Left, 1) rem 3);
2549 return UI_From_Int (Sign * (Tmp rem 6));
2551 -- m1 = 2; m2 = 5; M1 = 5; M2 = 6;
2554 Tmp := 5 * (Least_Sig_Digit (Left) rem 2) +
2555 6 * (Sum_Double_Digits (Left, -1) mod 5);
2556 return UI_From_Int (Sign * (Tmp rem 10));
2558 -- m1 = 3; m2 = 4; M1 = 4; M2 = 9;
2561 Tmp := 4 * (Sum_Double_Digits (Left, 1) rem 3) +
2562 9 * (Least_Sig_Digit (Left) rem 4);
2563 return UI_From_Int (Sign * (Tmp rem 12));
2568 -- Else fall through to general case
2570 -- The special case Length (Left) = Length (Right) = 1 in Div
2571 -- looks slow. It uses UI_To_Int when Int should suffice. ???
2578 pragma Warnings (Off, Quotient);
2581 (Left, Right, Quotient, Remainder,
2582 Discard_Quotient => True,
2583 Discard_Remainder => False);
2592 function UI_Sub (Left : Int; Right : Uint) return Uint is
2594 return UI_Add (Left, -Right);
2597 function UI_Sub (Left : Uint; Right : Int) return Uint is
2599 return UI_Add (Left, -Right);
2602 function UI_Sub (Left : Uint; Right : Uint) return Uint is
2604 if Direct (Left) and then Direct (Right) then
2605 return UI_From_Int (Direct_Val (Left) - Direct_Val (Right));
2607 return UI_Add (Left, -Right);
2615 function UI_To_CC (Input : Uint) return Char_Code is
2617 if Direct (Input) then
2618 return Char_Code (Direct_Val (Input));
2620 -- Case of input is more than one digit
2624 In_Length : constant Int := N_Digits (Input);
2625 In_Vec : UI_Vector (1 .. In_Length);
2629 Init_Operand (Input, In_Vec);
2631 -- We assume value is positive
2634 for Idx in In_Vec'Range loop
2635 Ret_CC := Ret_CC * Char_Code (Base) +
2636 Char_Code (abs In_Vec (Idx));
2648 function UI_To_Int (Input : Uint) return Int is
2650 if Direct (Input) then
2651 return Direct_Val (Input);
2653 -- Case of input is more than one digit
2657 In_Length : constant Int := N_Digits (Input);
2658 In_Vec : UI_Vector (1 .. In_Length);
2662 -- Uints of more than one digit could be outside the range for
2663 -- Ints. Caller should have checked for this if not certain.
2664 -- Fatal error to attempt to convert from value outside Int'Range.
2666 pragma Assert (UI_Is_In_Int_Range (Input));
2668 -- Otherwise, proceed ahead, we are OK
2670 Init_Operand (Input, In_Vec);
2673 -- Calculate -|Input| and then negates if value is positive. This
2674 -- handles our current definition of Int (based on 2s complement).
2675 -- Is it secure enough???
2677 for Idx in In_Vec'Range loop
2678 Ret_Int := Ret_Int * Base - abs In_Vec (Idx);
2681 if In_Vec (1) < Int_0 then
2694 procedure UI_Write (Input : Uint; Format : UI_Format := Auto) is
2696 Image_Out (Input, False, Format);
2699 ---------------------
2700 -- Vector_To_Uint --
2701 ---------------------
2703 function Vector_To_Uint
2704 (In_Vec : UI_Vector;
2712 -- The vector can contain leading zeros. These are not stored in the
2713 -- table, so loop through the vector looking for first non-zero digit
2715 for J in In_Vec'Range loop
2716 if In_Vec (J) /= Int_0 then
2718 -- The length of the value is the length of the rest of the vector
2720 Size := In_Vec'Last - J + 1;
2722 -- One digit value can always be represented directly
2724 if Size = Int_1 then
2726 return Uint (Int (Uint_Direct_Bias) - In_Vec (J));
2728 return Uint (Int (Uint_Direct_Bias) + In_Vec (J));
2731 -- Positive two digit values may be in direct representation range
2733 elsif Size = Int_2 and then not Negative then
2734 Val := In_Vec (J) * Base + In_Vec (J + 1);
2736 if Val <= Max_Direct then
2737 return Uint (Int (Uint_Direct_Bias) + Val);
2741 -- The value is outside the direct representation range and must
2742 -- therefore be stored in the table. Expand the table to contain
2743 -- the count and tigis. The index of the new table entry will be
2744 -- returned as the result.
2746 Uints.Increment_Last;
2747 Uints.Table (Uints.Last).Length := Size;
2748 Uints.Table (Uints.Last).Loc := Udigits.Last + 1;
2750 Udigits.Increment_Last;
2753 Udigits.Table (Udigits.Last) := -In_Vec (J);
2755 Udigits.Table (Udigits.Last) := +In_Vec (J);
2758 for K in 2 .. Size loop
2759 Udigits.Increment_Last;
2760 Udigits.Table (Udigits.Last) := In_Vec (J + K - 1);
2767 -- Dropped through loop only if vector contained all zeros