cosmopolitan/libc/nexgen32e/strncmp-hook.S

50 lines
2.6 KiB
ArmAsm

/*-*- mode:unix-assembly; indent-tabs-mode:t; tab-width:8; coding:utf-8 -*-│
vi: set et ft=asm ts=8 sw=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"
/ Dispatches to fastest strncmp() implementation.
/
/ @param rdi is first non-null NUL-terminated string pointer
/ @param rsi is second non-null NUL-terminated string pointer
/ @param rdx is maximum bytes to consider
/ @return rax is <0, 0, or >0 based on uint8_t comparison
.initbss 300,_init_strncmp
hook$strncmp:
.quad 0
.endobj hook$strncmp,globl,hidden
.previous
.init.start 300,_init_strncmp
#if !IsTiny()
ezlea strncmp$avx,ax
#if !X86_NEED(AVX)
ezlea tinystrncmp,dx
testb X86_HAVE(AVX)+kCpuids(%rip)
cmovz %rdx,%rax
#endif /* AVX */
#else
ezlea tinystrncmp,ax
#endif /* TINY */
stosq
.init.end 300,_init_strncmp
.source __FILE__