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/*
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_streq
zap_streq:
/*
char const * lstr
char const * rstr
*/
#if defined(__amd64__)
# rdi: Address of the current left character.
# rsi: Address of the current right character.
# rax: Current left character.
# rdx: Current right character.
# Iterate over the strings:
.loop:
# Copy the characters into registers:
movb (%rdi),%al
movb (%rsi),%dl
# Check if the characters are equal:
cmpb %al,%dl
jne .neq # If not, the strings also aren't equal.
# Check if we have reached the null-terminator:
testb %al,%al
jz .eq # If so, all previous characters have compared equal, and the strings are equal.
# Continue to the next characters:
incq %rdi
incq %rsi
jmp .loop
# The strings have compared equal:
.eq:
movb $0xFF,%al
ret
/* The strings have compared unequal: */
.neq:
movb $0x0,%al
ret
#endif
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