diff options
Diffstat (limited to 'zap/src/memfill.c')
-rw-r--r-- | zap/src/memfill.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/zap/src/memfill.c b/zap/src/memfill.c new file mode 100644 index 0000000..70982c4 --- /dev/null +++ b/zap/src/memfill.c @@ -0,0 +1,58 @@ +/* + 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_memfill\n" + + "zap_memfill:\n" + /* + void const * ptr + size_t num + uint_least8_t val + */ +#if defined(sus_arch_amd64) + /* rdi: Address of the current element. */ + /* rsi: Address of the element after the last element. */ + "addq %rdi,%rsi\n" + ".loop:\n" + "cmpq %rsi,%rdi\n" + "je .done\n" /* Exit loop if we have reached the final element. */ + "movb %dl,(%rdi)\n" + "incq %rdi\n" + "jmp .loop\n" /* Continue to next element. */ + ".done:\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 0x4(%esp),%ecx\n" + "addl 0x8(%esp),%ecx\n" + /* edx: Byte value. */ + "movb 0xC(%esp),%dl\n" + ".loop:\n" + "cmpl %eax,%ecx\n" + "je .done\n" /* Exit loop if we have reached the final element. */ + "movb %dl,(%eax)\n" + "incl %eax\n" + "jmp .loop\n" /* Continue to next element. */ + ".done:\n" + "ret\n" +#endif +); +#else +void zap_memfill(void * const _ptr,size_t const _num,uint_least8_t const _byte) { + uint_least8_t * pos = (uint_least8_t *)_ptr; + uint_least8_t * const afterbuf = pos + _num; + for (;pos != afterbuf;++pos) {*pos = _byte;} +} +#endif |