76 lines
1.3 KiB
ArmAsm
76 lines
1.3 KiB
ArmAsm
/* SPDX-License-Identifier: GPL-2.0-only */
|
|
/*
|
|
* Copyright (C) 2021 Arm Ltd.
|
|
*/
|
|
|
|
#include <linux/linkage.h>
|
|
#include <asm/assembler.h>
|
|
|
|
/*
|
|
* Find a character in an area of memory.
|
|
*
|
|
* Parameters:
|
|
* x0 - buf
|
|
* x1 - c
|
|
* x2 - n
|
|
* Returns:
|
|
* x0 - address of first occurrence of 'c' or 0
|
|
*/
|
|
|
|
#define L(label) .L ## label
|
|
|
|
#define REP8_01 0x0101010101010101
|
|
#define REP8_7f 0x7f7f7f7f7f7f7f7f
|
|
|
|
#define srcin x0
|
|
#define chrin w1
|
|
#define cntin x2
|
|
|
|
#define result x0
|
|
|
|
#define wordcnt x3
|
|
#define rep01 x4
|
|
#define repchr x5
|
|
#define cur_word x6
|
|
#define cur_byte w6
|
|
#define tmp x7
|
|
#define tmp2 x8
|
|
|
|
.p2align 4
|
|
nop
|
|
SYM_FUNC_START_WEAK_PI(memchr)
|
|
and chrin, chrin, #0xff
|
|
lsr wordcnt, cntin, #3
|
|
cbz wordcnt, L(byte_loop)
|
|
mov rep01, #REP8_01
|
|
mul repchr, x1, rep01
|
|
and cntin, cntin, #7
|
|
L(word_loop):
|
|
ldr cur_word, [srcin], #8
|
|
sub wordcnt, wordcnt, #1
|
|
eor cur_word, cur_word, repchr
|
|
sub tmp, cur_word, rep01
|
|
orr tmp2, cur_word, #REP8_7f
|
|
bics tmp, tmp, tmp2
|
|
b.ne L(found_word)
|
|
cbnz wordcnt, L(word_loop)
|
|
L(byte_loop):
|
|
cbz cntin, L(not_found)
|
|
ldrb cur_byte, [srcin], #1
|
|
sub cntin, cntin, #1
|
|
cmp cur_byte, chrin
|
|
b.ne L(byte_loop)
|
|
sub srcin, srcin, #1
|
|
ret
|
|
L(found_word):
|
|
CPU_LE( rev tmp, tmp)
|
|
clz tmp, tmp
|
|
sub tmp, tmp, #64
|
|
add result, srcin, tmp, asr #3
|
|
ret
|
|
L(not_found):
|
|
mov result, #0
|
|
ret
|
|
SYM_FUNC_END_PI(memchr)
|
|
EXPORT_SYMBOL_NOKASAN(memchr)
|