From d9194d46ef70e7c9f76b876b2439c24649d57d1e Mon Sep 17 00:00:00 2001
From: Aleksa Vuckovic <aleksav013@gmail.com>
Date: Sat, 28 Jan 2023 21:06:31 +0100
Subject: atomic test_and_set; spinlocks

---
 kernel/src/scheduler/atomic.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 kernel/src/scheduler/atomic.c

(limited to 'kernel/src/scheduler/atomic.c')

diff --git a/kernel/src/scheduler/atomic.c b/kernel/src/scheduler/atomic.c
new file mode 100644
index 0000000..41ce3b9
--- /dev/null
+++ b/kernel/src/scheduler/atomic.c
@@ -0,0 +1,27 @@
+#include <types.h>
+#include <atomic.h>
+#include <libk/stdio.h>
+#include <heap.h>
+
+void init_mutex(mutex_t* mutex)
+{
+	mutex->addr = (uint64_t*)kalloc(sizeof(uint64_t));
+	*(mutex->addr) = 0;
+}
+
+bool test_and_set(mutex_t mutex, bool value)
+{
+	bool rax;
+	__asm__ volatile ("lock xchg %%rax, (%%rbx);" : "=a"(rax) : "b"(mutex.addr), "a"(value));
+	return rax;
+}
+
+void lock(mutex_t mutex)
+{
+	while (test_and_set(mutex, 1)) ;
+}
+
+void unlock(mutex_t mutex)
+{
+	test_and_set(mutex, 0);
+}
-- 
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