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* Fixed overflow handling in i386 assembler implementations of fpc_div_qword and fpc_mod_qword.

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Resolves #23963.

git-svn-id: trunk@24362 -
This commit is contained in:
sergei 2013-04-29 01:12:45 +00:00
parent 1fea5a82c1
commit 97152cc41b
3 changed files with 35 additions and 13 deletions
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1
.gitattributes vendored
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@ -13383,6 +13383,7 @@ tests/webtbs/tw2382.pp svneol=native#text/plain
tests/webtbs/tw2388.pp svneol=native#text/plain
tests/webtbs/tw23912.pp svneol=native#text/plain
tests/webtbs/tw23962.pp svneol=native#text/plain
tests/webtbs/tw23963.pp svneol=native#text/plain
tests/webtbs/tw2397.pp svneol=native#text/plain
tests/webtbs/tw24007.pp svneol=native#text/plain
tests/webtbs/tw2409.pp svneol=native#text/plain

33
rtl/i386/int64p.inc
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@ -18,10 +18,10 @@
{$define FPC_SYSTEM_HAS_DIV_QWORD}
function fpc_div_qword(n,z : qword) : qword;assembler;[public,alias: 'FPC_DIV_QWORD']; compilerproc;
var
shift,lzz,lzn : longint;
saveebx,saveedi : longint;
saveebx,saveedi,saveesi : longint;
asm
movl %ebx,saveebx
movl %esi,saveesi
movl %edi,saveedi
{ the following piece of code is taken from the }
{ AMD Athlon Processor x86 Code Optimization manual }
@ -68,18 +68,23 @@
roll $1,%edi
divl %ebx
movl z,%ebx
movl %eax,%ecx
movl %eax,%esi // save quotient to esi
imull %eax,%edi
mull n
addl %edi,%edx
setcb %cl // cl:edx:eax = 65 bits quotient*divisor
movl z+4,%edi // edi:ebx = dividend
subl %eax,%ebx
movl %ecx,%eax
movl z+4,%ecx
sbbl %edx,%ecx
sbbl $0,%eax
movb $0,%al
sbbl %edx,%edi
sbbb %cl,%al
sbbl $0,%esi
xorl %edx,%edx
movl %esi,%eax
.Lexit:
movl saveebx,%ebx
movl saveesi,%esi
movl saveedi,%edi
end;
@ -87,7 +92,6 @@
{$define FPC_SYSTEM_HAS_MOD_QWORD}
function fpc_mod_qword(n,z : qword) : qword;assembler;[public,alias: 'FPC_MOD_QWORD']; compilerproc;
var
shift,lzz,lzn : longint;
saveebx,saveedi : longint;
asm
movl %ebx,saveebx
@ -139,19 +143,22 @@
roll $1,%edi
divl %ebx
movl z,%ebx
movl %eax,%ecx
imull %eax,%edi
mull n
addl %edi,%edx
subl %eax,%ebx
movl z+4,%ecx
setcb %cl // cl:edx:eax = 65 bits quotient*divisor
movl z+4,%edi
subl %eax,%ebx // subtract (quotient*divisor) from dividend
movb $0,%al
sbbl %edx,%edi
sbbb %cl,%al // if carry is set now, the quotient was off by 1,
// and we need to add divisor to result
movl n,%eax
sbbl %edx,%ecx
sbbl %edx,%edx
andl %edx,%eax
andl n+4,%edx
addl %ebx,%eax
adcl %ecx,%edx
adcl %edi,%edx
.Lexit:
movl saveebx,%ebx
movl saveedi,%edi

14
tests/webtbs/tw23963.pp Normal file
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@ -0,0 +1,14 @@
{$mode objfpc}
var
Dividend, Divisor, Quotient : QWord;
begin
Dividend := QWord( $ffffffffffffffff );
Divisor := QWord( $100000003 );
Quotient := dividend div divisor;
if quotient <> $FFFFFFFD then
Halt(1);
Quotient := dividend mod divisor;
if quotient <> 8 then
Halt(2);
end.