diff options
Diffstat (limited to 'rgo/src/memeq.S')
| -rw-r--r-- | rgo/src/memeq.S | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/rgo/src/memeq.S b/rgo/src/memeq.S new file mode 100644 index 0000000..c3a9a63 --- /dev/null +++ b/rgo/src/memeq.S @@ -0,0 +1,60 @@ +/* + 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 |