64 lines
2.8 KiB
ArmAsm
64 lines
2.8 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/nexgen32e/x86feature.h"
|
|
#include "libc/dce.h"
|
|
#include "libc/macros.h"
|
|
|
|
/ Searches for last instance of byte in memory region.
|
|
/
|
|
/ @param rdi points to data to search
|
|
/ @param esi is treated as unsigned char
|
|
/ @param rdx is byte length of rdi
|
|
/ @return rax is address of last %sil in %rdi, or NULL
|
|
/ @note AVX2 requires Haswell (2014+) or Excavator (2015+)
|
|
/ @asyncsignalsafe
|
|
memrchr:.leafprologue
|
|
.profilable
|
|
#if !IsTiny()
|
|
cmp $32,%rdx
|
|
jb 5f
|
|
testb X86_HAVE(AVX2)+kCpuids(%rip)
|
|
jz 5f
|
|
vmovd %esi,%xmm0
|
|
vpbroadcastb %xmm0,%ymm0
|
|
3: vmovdqu -32(%rdi,%rdx),%ymm1
|
|
vpcmpeqb %ymm1,%ymm0,%ymm1
|
|
vpmovmskb %ymm1,%eax
|
|
lzcnt %eax,%eax
|
|
mov %eax,%ecx
|
|
sub %rcx,%rdx
|
|
cmp $32,%eax
|
|
jne 5f
|
|
cmp $31,%rdx
|
|
ja 3b
|
|
vzeroupper
|
|
#endif
|
|
5: xor %eax,%eax
|
|
mov %rdx,%rcx
|
|
6: sub $1,%rcx
|
|
jb 9f
|
|
cmp %sil,-1(%rdi,%rdx)
|
|
mov %rcx,%rdx
|
|
jne 6b
|
|
lea (%rdi,%rcx),%rax
|
|
9: .leafepilogue
|
|
.endfn memrchr,globl
|
|
.source __FILE__
|