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fixed bigint division bugs and added incomplete bigint-to-string conversion function

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hyung-hwan
2014-03-05 18:06:54 +00:00
parent 6d94c9b515
commit 4e7f1ce8e4
3 changed files with 156 additions and 31 deletions
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169
h2/lib/h2-scheme-bigint.adb
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@ -88,7 +88,7 @@ package body Bigint is
Y: in Object_Pointer) return Standard.Boolean is
pragma Inline (Is_Less_Unsigned);
begin
return Is_Less_Unsigned_Array (X.Half_Word_Slot, X.Size, Y.Half_Word_Slot, Y.Size);
return Is_Less_Unsigned_Array(X.Half_Word_Slot, X.Size, Y.Half_Word_Slot, Y.Size);
end Is_Less_Unsigned;
function Is_Less (X: in Object_Pointer;
@ -124,13 +124,13 @@ package body Bigint is
function Copy_Upto (Interp: access Interpreter_Record;
X: in Object_Pointer;
Last: in Half_Word_Object_Size) return Object_Pointer is
pragma Assert (Last < X.Size);
pragma Assert (Last <= X.Size);
A: aliased Object_Pointer := X;
Z: Object_Pointer;
begin
Push_Top (Interp.all, A'Unchecked_Access);
Z := Make_Bigint(Interp, Size => Last);
Pop_Tops (Interp.all, 1);
Z := Make_Bigint(Interp, Size => Last);
Pop_Tops (Interp.all, 1);
Z.Sign := A.Sign;
Z.Half_Word_Slot := A.Half_Word_Slot(1 .. Last);
return Z;
@ -148,7 +148,7 @@ package body Bigint is
end loop;
return Last;
end Count_Effective_Slots;
function Normalize (Interp: access Interpreter_Record;
X: in Object_Pointer) return Object_Pointer is
Last: Half_Word_Object_Size;
@ -165,7 +165,7 @@ package body Bigint is
when 2 =>
declare
W: Object_Word := Make_Word (X.Half_Word_Slot(1), X.Half_Word_Slot(2));
W: Object_Word := Make_Word(X.Half_Word_Slot(1), X.Half_Word_Slot(2));
begin
if X.Sign = Negative_Sign then
if W in 0 .. Object_Word(-Object_Signed_Word(Object_Integer'First)) then
@ -309,6 +309,9 @@ package body Bigint is
Borrowed_Word: constant Object_Word := Object_Word(Object_Half_Word'Last) + 1;
Borrow: Object_Half_Word := 0;
begin
pragma Assert (not Is_Less_Unsigned_Array(X, XS, Y, YS)); -- The caller must ensure that X >= Y
for I in 1 .. YS loop
W := Object_Word(Y(I)) + Object_Word(Borrow);
if Object_Word(X(I)) >= W then
@ -439,7 +442,6 @@ package body Bigint is
begin
pragma Assert (not Is_Less_Unsigned(A, B)); -- The caller must ensure that X >= Y
Push_Top (Interp, A'Unchecked_Access);
Push_Top (Interp, B'Unchecked_Access);
Push_Top (Interp, Quo'Unchecked_Access);
@ -482,27 +484,23 @@ package body Bigint is
Tmp.Half_Word_Slot := (others => 0);
Multiply_Unsigned_Array (Cand, Cand_Size, Sor.Half_Word_Slot, Sor_Size, Tmp.Half_Word_Slot);
Tmp_Size := Count_Effective_Slots(Tmp);
-- Check if the divident is less than the multiplication result.
if Is_Less_Unsigned_Array(Dend.Half_Word_Slot, Dend_Size, Tmp.Half_Word_Slot, Tmp_Size) then
-- If so, decrement the candidate by 1.
Quo.Half_Word_Slot(I) := Cand(1) - 1;
-- Dividend := Dividend - Tmp
Subtract_Unsigned_Array (Dend.Half_Word_Slot, Dend_Size, Tmp.Half_Word_Slot, Tmp_Size, Dend.Half_Word_Slot);
Dend_Size := Count_Effective_Slots(Dend);
-- Divident := Dividdent - Divisor
Subtract_Unsigned_Array (Dend.Half_Word_Slot, Dend_Size, Sor.Half_Word_Slot, Sor_Size, Dend.Half_Word_Slot);
Dend_Size := Count_Effective_Slots(Dend);
-- Check if the dividend is less than the multiplication result. Dividend < Tmp
if Is_Less_Unsigned_Array(Dend.Half_Word_Slot, Dend_Size, Tmp.Half_Word_Slot, Tmp_Size) then
-- If so, decrement the candidate by 1.
Quo.Half_Word_Slot(I - B.Size + 1) := Cand(1) - 1;
-- Tmp := Tmp - Divisor
Subtract_Unsigned_Array (Tmp.Half_Word_Slot, Tmp_Size, Sor.Half_Word_Slot, Sor_Size, Tmp.Half_Word_Slot);
Tmp_Size := Count_Effective_Slots(Tmp);
else
-- If not, the candidate is the right guess.
Quo.Half_Word_Slot(I) := Cand(1);
-- Dividend := Dividend - Tmp
Subtract_Unsigned_Array (Dend.Half_Word_Slot, Dend_Size, Tmp.Half_Word_Slot, Tmp_Size, Dend.Half_Word_Slot);
Dend_Size := Count_Effective_Slots(Dend);
Quo.Half_Word_Slot(I - B.Size + 1) := Cand(1);
end if;
-- Dividend := Dividend - Tmp
Subtract_Unsigned_Array (Dend.Half_Word_Slot, Dend_Size, Tmp.Half_Word_Slot, Tmp_Size, Dend.Half_Word_Slot);
Dend_Size := Count_Effective_Slots(Dend);
end if;
-- Shift the divisor right by 1 slot
@ -642,7 +640,9 @@ package body Bigint is
else
Sign := Negative_Sign;
end if;
Divide_Unsigned (Interp, A, B, C, D);
C.Sign := Sign;
D.Sign := Sign;
@ -658,10 +658,127 @@ package body Bigint is
procedure To_String (Interp: in out Interpreter_Record;
X: in Object_Pointer;
Radix: in Object_Half_Word;
Radix: in Object_Half_Word; -- TODO define the radix type to a subtype range 2 .. 32
Z: out Object_Pointer) is
A: aliased Object_Pointer;
B: aliased Object_Pointer;
R: aliased Object_Pointer;
W, V: Object_Word;
Sign: Object_Sign;
Radlen: Object_Word;
Seglen: Object_Word;
-- TODO: estimate the length of the character array and create a temporary string object instead of this array.
QQQ: Object_Character_Array (1.. X.Size * Object_Half_Word'Size);
QL: Character_Object_Size := 0;
begin
if Is_Integer(X) then
-- TODO: change this
ada.text_io.put_line(Object_Integer'Image(Pointer_To_Integer(X)));
return;
end if;
if X.Size <= 2 then
--TODO: sign;
if X.Size = 2 then
W := Make_Word(X.Half_Word_Slot(1), X.Half_Word_Slot(2));
else
W := Object_Word(X.Half_Word_Slot(1));
end if;
ada.text_io.put_line(Object_Word'Image(W));
return;
end if;
-- Find the largest multiple of Radix that is less than or
-- equal to Object_Word'Last.
Radlen := 1;
W := Object_Word(Radix);
loop
V := W * Object_Word(Radix);
if V = W then
Radlen := Radlen + 1;
W := V;
exit;
elsif V < W then
exit;
end if;
Radlen := Radlen + 1;
W := V;
end loop;
Push_Top (Interp, R'Unchecked_Access);
Push_Top (Interp, B'Unchecked_Access);
Push_Top (Interp, A'Unchecked_Access);
A := Copy_Upto(Interp.Self, X, X.Size);
B := Make_Bigint(Interp.Self, Size => 2);
B.Half_Word_Slot(1) := Get_Low(W);
B.Half_Word_Slot(2) := Get_High(W);
Sign := A.Sign;
A.Sign := Positive_Sign;
loop
if Is_Less_Unsigned(B, A) then
Divide_Unsigned (Interp, A, B, A, R);
A := Copy_Upto(Interp.Self, A, Count_Effective_Slots(A)); -- partial normalization
else
R := A;
end if;
if R.Size = 1 then
W := Object_Word(R.Half_Word_Slot(1));
else
W := Make_Word(R.Half_Word_Slot(1), R.Half_Word_Slot(2));
end if;
Seglen := 0;
loop
V := W rem Object_Word(Radix);
Seglen := Seglen + 1;
QL := QL + 1;
if V in 0 .. 9 then
QQQ(QL) := Object_Character'Val(Object_Character'Pos(Ch.Zero) + V);
else
QQQ(QL) := Object_Character'Val(Object_Character'Pos(Ch.UC_A) + V - 10);
end if;
W := W / Object_Word(Radix);
exit when W = 0;
end loop;
exit when R = A; -- Reached the last block
-- Fill with zeros if it's not the last block
for I in Seglen + 1 .. Radlen loop
QL := QL + 1;
QQQ(QL) := Object_Character'Val(Object_Character'Pos(Ch.Zero));
end loop;
end loop;
if Sign = Negative_Sign then
Ada.Text_IO.Put ('-');
end if;
for I in reverse 1 .. QL loop
Ada.Text_IO.Put (Standard.Character'Val(Object_Character'Pos(QQQ(I))));
end loop;
ada.text_io.new_line;
Pop_Tops (Interp, 3);
-- TODO:
--Z := Make_String_Object (...);
end To_String;
procedure From_String (Interp: in out Interpreter_Record;
X: in Object_Pointer;
Radix: in Object_Half_Word;
Z: out Object_Pointer) is
begin
null;
end To_String;
end From_String;
end Bigint;