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Diffstat (limited to 'rgo/src/memfill.S')
-rw-r--r-- | rgo/src/memfill.S | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/rgo/src/memfill.S b/rgo/src/memfill.S new file mode 100644 index 0000000..3c4fb1f --- /dev/null +++ b/rgo/src/memfill.S @@ -0,0 +1,38 @@ +/* + 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_memfill + +rgo_memfill: +#if defined(__x86_64__) + /* + rdi: void const * ptr + rsi: size_t num + dl: int_least8_t val + */ + /* We don't need to preserve any of the registers we use according to the ABI. */ + /* rcx: Address of the current element. */ + movq %rdi,%rcx + /* r8: Address of the last element. */ + movq %rdi,%r8 + addq %rsi,%r8 +.loop: + cmpq %r8,%rcx + je .done /* Exit loop if we have reached the final element. */ + movb %dl,(%rcx) + incq %rcx /* Continue to next element. */ + jmp .loop +.done: + ret +#endif |