# 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/.

.globl zap_strfill

zap_strfill:
# Address of the current character:
#define addr  %rax
# Address of the first character of the string:
#define start %rdi
# Fill character:
#define chr   %sil

	movq start,addr

	# Iterate over string:
.loop:

	# Check if we have reached the null-terminator:
	cmpb $0x0,(addr) # if (*addr == 0x0)
	je .done         # goto done

	# Set the value of the current element:
	movb chr,(addr) # *addr = chr

	# Continue to next character:
	incq addr # ++addr
	jmp .loop # goto loop

	# Finish:
.done:

	# Get the length of the string:
	subq start,addr # addr -= start

	ret # return addr