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/*
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_memeq
rgo_memeq:
#if defined(__x86_64__)
/*
rdi: void const * lptr
rsi: size_t num
rdx: void const * rptr
*/
/* rcx: Address of the current left element. */
movq %rdi,%rcx
/* r8: Address of the current right element. */
movq %rdx,%r8
/* r9: Number of remaining elements. */
movq %rsi,%r9
/* r10: Temporary. */
/* r11: Temporary. */
.wrdeq:
cmpq $0x8,%r9
jl .byteeq
movq (%rcx),%r10
movq (%r8),%r11
cmpq %r10,%r11
jz .neq
addq $0x8,%rcx
addq $0x8,%r8
subq $0x8,%r9
jmp .wrdeq
.byteeq:
testq %r9,%r9
jz .eq /* If we have reached the final element, all previous elements have compared equal, and the memory sequences are equal. */
movb (%rcx),%r10b
movb (%r8),%r11b
cmpb %r10b,%r11b
jne .neq
incq %rcx
incq %r8
decq %r9
jmp .byteeq
.eq:
mov $0x1,%rax
ret
.neq:
mov $0x0,%rax
ret
#endif
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