cosmopolitan/libc/nexgen32e/strsak32.S

183 lines
5.7 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/macros.h"
/ Returns pointer to first instance of character.
/
/ @param rdi is a non-null NUL-terminated wchar_t string pointer
/ @param esi is the search word
/ @return rax points to character, or to NUL word if not found
/ @note this won't return NULL if search character is NUL
wcschrnul:
.leafprologue
.profilable
or $-1,%r9
jmp 0f
/ Returns pointer to first instance of character.
/
/ @param rdi is a non-null NUL-terminated wchar_t string pointer
/ @param esi is the search word
/ @return rax points to first result, or NULL if not found
/ @note this won't return NULL if search character is NUL
/ @asyncsignalsafe
wcschr: .leafprologue
.profilable
xor %r9,%r9
0: mov %esi,%edx
xor %r11d,%r11d
pushpop -1,%rsi
xor %r8,%r8
jmp wcssak
/ Returns length of wchar_t string w/ security blankets.
/
/ This is like wcsnlen() except it'll return 0 if (1) RDI is NULL
/ or (2) a NUL-terminator wasn't found in the first RSI chars.
/
/ @param rdi is a nullable NUL-terminated wchar_t string pointer
/ @param rsi is the maximum number of chars to consider
/ @return rax is the number of chars, excluding the NUL
wcsnlen_s:
.leafprologue
.profilable
xor %eax,%eax
xor %r10d,%r10d
test %rdi,%rdi
jnz 0f
.leafepilogue
.endfn wcsnlen_s,globl
/ Returns length of NUL-terminated wchar_t string.
/
/ @param rdi is non-null NUL-terminated wchar_t string pointer
/ @return rax is the number of chars, excluding the NUL
/ @asyncsignalsafe
wcslen: or $-1,%rsi
/ fallthrough
/ Returns length of NUL-terminated memory, with limit.
/
/ @param rdi is non-null memory
/ @param rsi is the maximum number of chars to consider
/ @return rax is the number of chars, excluding the NUL
/ @asyncsignalsafe
wcsnlen:.leafprologue
.profilable
or $-1,%r10
0: xor %edx,%edx
xor %r11d,%r11d
mov %rdi,%r8
jmp wcssak
/ Returns pointer to first instance of character in range.
/
/ @param rdi is a non-null pointer to memory
/ @param esi is the search word
/ @return rax points to word if found, or else undefined behavior
rawwmemchr:
or $-1,%rdx
/ fallthrough
/ Returns pointer to first instance of character in range.
/
/ @param rdi is a non-null pointer to memory
/ @param esi is the int32_t search word (officially wchar_t)
/ @param rdx is length of memory in chars
/ @return rax points to word if found or NULL
/ @asyncsignalsafe
wmemchr:.leafprologue
.profilable
xor %r8,%r8
xor %r10,%r10
mov %rdx,%rcx
mov %esi,%edx
mov %esi,%r11d
mov %rcx,%rsi
/ fallthrough
/ Swiss army knife of wchar_t string scanning.
/ Seven fast functions in one.
/
/ @param rdi is non-null wchar_t string memory
/ @param rsi is max number of chars to consider
/ @param edx is search character #1
/ @param r11d is search character #2
/ @param r8 is subtracted from result (for length vs. pointer)
/ @param r9 masks result if r11w is found (for NUL vs. NULL)
/ @param r10 masks result on chars exhausted (for length v. NULL)
/ @return rax end pointer after r8/r9/r10 modifications
wcssak: lea -4(%rdi),%rax
.align 16
1: add $4,%rax
sub $1,%rsi
jb .Lend
test $31,%al
jz .Lfast
.Lint: mov (%rax),%ecx
cmp %ecx,%edx
je .Ldone
cmp %ecx,%r11d
je .Lnul
jmp 1b
.Ldone: sub %r8,%rax
jmp .Lret
.Lend: mov %r10,%r9
.Lnul: sub %r8,%rax
and %r9,%rax
.Lret: test %r8,%r8
jz 0f
shr $2,%rax
0: .leafepilogue
.Lslow: add $8,%rsi
jmp .Lint
.Lfast:
#if !X86_NEED(AVX2)
testb X86_HAVE(AVX2)+kCpuids(%rip)
jz .Lint
#endif
movd %edx,%xmm0
movd %r11d,%xmm1
vpbroadcastd %xmm0,%ymm0
vpbroadcastd %xmm1,%ymm1
sub $32,%rax
1: add $32,%rax
sub $8,%rsi
jb .Lslow
vmovdqa (%rax),%ymm2
vpcmpeqd %ymm0,%ymm2,%ymm3
vpcmpeqd %ymm1,%ymm2,%ymm2
vpor %ymm3,%ymm2,%ymm2
vpmovmskb %ymm2,%ecx
bsf %ecx,%ecx
je 1b
vzeroupper
add %rcx,%rax
jmp .Lint
.endfn wcssak
.endfn wmemchr,globl
.endfn rawwmemchr,globl
.endfn wcsnlen,globl
.endfn wcslen,globl
.endfn wcschr,globl
.endfn wcschrnul,globl
.source __FILE__