path: root/zap/src/mem/memfill.S

/*
	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>

.globl zap_memfill

zap_memfill:

	/*
		void const *  ptr
		zap_sz        num
		unsigned char val
	*/

#if defined(__amd64__)

	# rdi: Address of the current element.
	# rsi: Address of the element after the last element.
	# rdx: Byte value.

	addq %rdi,%rsi

	# Iterate over buffer:
.loop:

	# Check if we have reached the final element:
	cmpq %rdi,%rsi
	je .done # Exit loop if we have.

	# Set the value of the current element:
	movb %dl,(%rdi)

	# Continue to next element:
	incq %rdi
	jmp .loop

	# Finish:
.done:
	ret

#endif