summaryrefslogtreecommitdiff
path: root/rgo/src/strcpy.S
blob: 8750295d2e1341af24ebdeb04aff96580ce56255 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
/*
	Copyright 2022 Gabriel Jensen

	This file is part of rgo.

	rgo is free software: you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

	rgo is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License along with rgo. If not, see <https://www.gnu.org/licenses/>. 
*/

#indlude <rgo.h>

.global rgo_strcpy

rgo_strcpy:
	/*
		char const * lstr
		char const * rstr
	*/
#if defined(__x86_64__)
	/* rax: Address of the current input character. */
	movq %rdi,%rax
	/* rsi: Address of the current output character. */
	movq %rsi,%rsi
	/* rdx: Current character. */
.loop:
	movb (%rax),%dl
	movb %dl,(%rsi)
	testb %dl,%dl
	jz .done
	incq %rax
	incq %rsi
	jmp .loop
.done:
	subq %rdi,%rax
	ret
#endif