cosmopolitan/libc/nexgen32e/strcmp-avx.S

91 lines
3.2 KiB
ArmAsm

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 tw=8 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify │
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License. │
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. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software │
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/macros.h"
/ Compares NUL-terminated strings w/ AVX (2011+)
/
/ @param rdi first string
/ @param rsi second string
/ @return 0 if equal, etc.
/ @asyncsignalsafe
strcmp$avx:
or $-1,%rdx
/ fallthrough
.endfn strcmp$avx,globl,hidden
/ Compares NUL-terminated strings, with byte limit.
/
/ @param rdi first string
/ @param rsi second string
/ @param rdx maximum number of bytes to compare
/ @return 0 if equal, etc.
/ @asyncsignalsafe
strncmp$avx:
.leafprologue
.profilable
cmp %rsi,%rdi
je 1f
mov $-16,%rcx
vpxor %xmm0,%xmm0,%xmm0
vpcmpeqd %xmm1,%xmm1,%xmm1
3: add $16,%rcx
4: lea 16(%rcx),%rax
cmp %rdx,%rax
ja 9f
lea (%rdi,%rcx),%eax
and $0xfff,%eax
cmp $0xff0,%eax
ja 9f
lea (%rsi,%rcx),%eax
and $0xfff,%eax
cmp $0xff0,%eax
jbe 7f
9: cmpq %rcx,%rdx
je 1f
movzbl (%rdi,%rcx),%r8d
movzbl (%rsi,%rcx),%r9d
mov %r8d,%eax
sub %r9d,%eax
testl %r8d,%r8d
je 5f
incq %rcx
testl %eax,%eax
je 4b
jmp 5f
1: xor %eax,%eax
5: .leafepilogue
7: vmovdqu (%rsi,%rcx),%xmm3
vpcmpeqb (%rdi,%rcx),%xmm3,%xmm2
vpcmpeqb %xmm0,%xmm3,%xmm3
vpandn %xmm1,%xmm2,%xmm2
vpor %xmm3,%xmm2,%xmm2
vpmovmskb %xmm2,%eax
bsf %eax,%eax
jz 3b
mov %eax,%edx
add %rdx,%rdi
movzbl (%rcx,%rdi),%eax
add %rdx,%rsi
movzbl (%rcx,%rsi),%ecx
sub %ecx,%eax
jmp 5b
.endfn strncmp$avx,globl,hidden
.source __FILE__