| /* 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) |
