1 files changed, 46 insertions, 0 deletions
diff --git a/kernel/arch/x86_64/asm/spinlock.s b/kernel/arch/x86_64/asm/spinlock.s
new file mode 100644
index 0000000..1c69820
--- /dev/null
+++ b/kernel/arch/x86_64/asm/spinlock.s
@@ -0,0 +1,46 @@
+/*
+ * 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