/*
	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:
	/*
		void const * ptr
		size_t       num
		uint8_t      val
	*/
#if defined(__i386__)
	/* eax: Address of the current element. */
	movl 0x4(%esp),%eax
	/* ecx: Address of the element after the last element. */
	movl 0x4(%esp),%ecx
	addl 0x8(%esp),%ecx
	/* rdx: Byte value. */
	movb 0xC(%esp),%dl
.loop:
	cmpl %eax,%ecx
	je .done /* Exit loop if we have reached the final element. */
	movb %dl,(%eax)
	incl %eax
	jmp .loop /* Continue to next element. */
.done:
	ret
#elif defined(__x86_64__)
	/* rdi: Address of the current element. */
	/* rsi: Address of the element after the last element. */
	addq %rdi,%rsi
.loop:
	cmpq %rsi,%rdi
	je .done /* Exit loop if we have reached the final element. */
	movb %dl,(%rdi)
	incq %rdi
	jmp .loop /* Continue to next element. */
.done:
	ret
#endif