/*
	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/>. 
*/

#include <rgo.h>

.global rgo_memfill

rgo_memfill:
#if defined(__x86_64__)
	/*
		rdi: void const * ptr
		rsi: size_t       num
		dl:  int_least8_t val
	*/
	/* We don't need to preserve any of the registers we use according to the ABI. */
	/* rcx: Address of the current element. */
	movq %rdi,%rcx
	/* rcx: Address of the element after the last element. */
	movq %rdi,%r8
	addq %rsi,%r8
.loop:
	cmpq %r8,%rcx
	je .done /* Exit loop if we have reached the final element. */
	movb %dl,(%rcx)
	incq %rcx /* Continue to next element. */
	jmp .loop
.done:
	ret
#endif