/*
 * 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