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/*
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>
#if defined(zap_priv_fastimpl)
__asm__ (
".globl zap_strcpy\n"
"zap_strcpy:\n"
/*
char const * in
char const * out
*/
#if defined(sus_arch_amd64)
/* rax: Address of the current input character. */
"movq %rdi,%rax\n"
/* rsi: Address of the current output character. */
"movq %rsi,%rsi\n"
/* rdx: Current character. */
".loop:\n"
"movb (%rax),%dl\n" /* Move current the character into a register... */
"movb %dl,(%rsi)\n" /* ... and then back into memory. */
"testb %dl,%dl\n" /* Check if we have reached the null-terminator... */
"jz .done\n" /* ... and if so, we are finished copying. */
"incq %rax\n" /* Increment the positions. */
"incq %rsi\n"
"jmp .loop\n" /* Restart the loop. */
".done:\n"
"subq %rdi,%rax\n" /* Get the length of the string we copyied. */
"decq %rdi\n" /* We do not count the null-terminator in the string length. */
"ret\n"
#elif defined(sus_arch_ia32)
/* eax: Address of the current input character. */
"movl 0x4(%esp),%eax\n"
/* ecx: Address of the current output character. */
"movl 0x8(%esp),%ecx\n"
/* edx: Current character. */
".loop:\n"
"movb (%eax),%dl\n" /* Move current the character into a register... */
"movb %dl,(%ecx)\n" /* ... and then back into memory. */
"testb %dl,%dl\n" /* Check if we have reached the null-terminator... */
"jz .done\n" /* ... and if so, we are finished copying. */
"incl %eax\n" /* Increment the positions. */
"incl %ecx\n"
"jmp .loop\n" /* Restart the loop. */
".done:\n"
"subl 0x4(%esp),%eax\n" /* Get the length of the string we copyied. */
"decl %ecx \n" /* We do not count the null-terminator in the string length. */
"ret\n"
#endif
);
#else
size_t zap_strcpy(char const * const _in,char * const _out) {
char const * inpos = _in;
char * outpos = _out;
for (;;++inpos,++outpos) {
char const chr = *inpos;
*outpos = chr;
if (chr == '\x0') {return (size_t)(inpos - _in);}
}
sus_unreach();
}
#endif
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