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/*
* Copyright (C) 2025 Danny Holman <dholman@gymli.org>
*
* This file is part of BoxOS, a free and open-source Unix-like operating
* system.
*
* BoxOS is free software; you can redistribute it and/or modify under the
* terms of the GNU General Public License as published by the Free Software
* Foundation; either version 2 of the License, or (at your option) any later
* version.
*
* BoxOS is distributed in the hope it will be useful, but WITHOUT ANY WARRANTY;
* without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
* PARTICULAR PURPOSE. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* BoxOS; if not, see <https://www.gnu.org/licenses/>.
*/
.section .text
.global acquire_lock
acquire_lock:
pushq %rbp
movq %rsp, %rbp
movq $0, %rax
lock bts %rax, (%rdi)
.loop:
pause
testq %rax, %rax
jz .done
jmp .loop
.done:
popq %rbp
ret
.global release_lock
release_lock:
pushq %rbp
movq %rsp, %rbp
movq $0, %rax
lock btr %rax, (%rdi)
ret
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