fpc/rtl/x86_64/strings.inc
Michael VAN CANNEYT 5ce739135b * Char -> AnsiChar
2023-07-14 17:26:10 +02:00

62 lines
1.7 KiB
PHP

{
This file is part of the Free Pascal run time library.
Copyright (c) 2003 by Florian Klaempfl, member of the
Free Pascal development team
Processor dependent part of strings.pp, that can be shared with
sysutils unit.
See the file COPYING.FPC, included in this distribution,
for details about the copyright.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
**********************************************************************}
{$ASMMODE GAS}
{$ifndef FPC_UNIT_HAS_STRCOMP}
{$define FPC_UNIT_HAS_STRCOMP}
function StrComp(Str1, Str2: PAnsiChar): SizeInt;assembler;nostackframe;
asm
{$ifndef win64}
movq %rsi,%rdx
movq %rdi,%rcx
{$endif win64}
subq %rcx,%rdx
.balign 16
.Lloop: { unrolled 4 times }
movb (%rcx),%al
cmpb (%rdx,%rcx),%al
jne .Ldiff
testb %al,%al
jz .Leq
movb 1(%rcx),%al
cmpb 1(%rdx,%rcx),%al
jne .Ldiff
testb %al,%al
jz .Leq
movb 2(%rcx),%al
cmpb 2(%rdx,%rcx),%al
jne .Ldiff
testb %al,%al
jz .Leq
movb 3(%rcx),%al
add $4,%rcx
cmpb -1(%rdx,%rcx),%al
jne .Ldiff
testb %al,%al
jnz .Lloop
.Leq:
xorq %rax,%rax
jmp .Lexit
.Ldiff:
sbbq %rax,%rax { -1 if CF was set, 0 otherwise }
orb $1,%al { 0 becomes 1, -1 remains unchanged }
.Lexit:
end;
{$endif FPC_UNIT_HAS_STRCOMP}