diff options
Diffstat (limited to 'zap/src/fndbyte.c')
-rw-r--r-- | zap/src/fndbyte.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/zap/src/fndbyte.c b/zap/src/fndbyte.c new file mode 100644 index 0000000..85fc14d --- /dev/null +++ b/zap/src/fndbyte.c @@ -0,0 +1,77 @@ +/* + Copyright 2022 Gabriel Jensen. + This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0. + If a copy of the MPL was not distributed with this file, You can obtain one at https://mozilla.org/MPL/2.0/. +*/ + +#include <zap/priv.h> + +#include <stddef.h> +#include <stdint.h> + +#if defined(zap_priv_fastimpl) +__asm__ ( + ".global zap_fndbyte\n" + + "zap_fndbyte:\n" + /* + void const * ptr + size_t num + uint_least8_t byte + */ +#if defined(sus_arch_amd64) + /* rax: Address of the current element. */ + "movq %rdi,%rax\n" + /* rsi: Address of the element after the last element. */ + "addq %rdi,%rsi\n" + /* rcx: Current element. */ + ".loop:\n" + "cmpq %rax,%rsi\n" + "je .nfnd\n" /* We have went through the entire array without finding the byte. */ + "movb (%rax),%cl\n" + "cmpb %cl,%dl\n" + "je .fnd\n" /* We have found the byte. */ + "incq %rax\n" + "jmp .loop\n" + ".fnd:\n" + "subq %rdi,%rax\n" + "ret\n" + ".nfnd:\n" + "movq $0xFFFFFFFFFFFFFFFF,%rax\n" + "ret\n" +#elif defined(sus_arch_ia32) + /* eax: Address of the current element. */ + "movl 0x4(%esp),%eax\n" + /* ecx: Address of the element after the last element. */ + "movl 0x8(%esp),%ecx\n" + "addl %eax,%ecx\n" + /* edx: Byte value. */ + "movb 0xC(%esp),%dl\n" + /* ebx: Current element. */ + "pushl %ebx\n" + ".loop:\n" + "cmpl %eax,%ecx\n" + "je .nfnd\n" /* We have went through the entire array without finding the byte. */ + "movb (%eax),%bl\n" + "cmpb %bl,%dl\n" + "je .fnd\n" /* We have found the byte. */ + "incl %eax\n" + "jmp .loop\n" + ".fnd:\n" + "popl %ebx\n" + "subl 0x4(%esp),%eax\n" + "ret\n" + ".nfnd:\n" + "popl %ebx\n" + "movl $0xFFFFFFFF,%eax\n" + "ret\n" +#endif +); +#else +size_t zap_fndbyte(void const * const _ptr,size_t const _num,uint_least8_t const _byte) { + uint_least8_t const * ptr = (uint_least8_t const *)_ptr; + uint_least8_t const * const afterbuf = ptr + _num; + for (;ptr != afterbuf;++ptr) {sus_unlikely (*ptr == _byte) {return ptr - (uint_least8_t const *)_ptr;}} + return zap_typlit_usz(-0x1); +} +#endif |