Add ARM spinlock

os/Makefile

@@ -1,22 +0,0 @@
-CC = arm-none-eabi-gcc
-AS = arm-none-eabi-as
-LD = arm-none-eabi-ld
-CPU = -mcpu=cortex-m4
-THUMB = -mthumb
-
-LDFLAGS = -T linker.ld
-CFLAGS = -c $(CPU) $(THUMB) -g
-
-all: main.o process.o scheduler.o
-
-main.o: main.c
-	$(CC) $(CFLAGS) main.c -o main.o
-
-scheduler.o: scheduler.c
-	$(CC) $(CFLAGS) scheduler.c -o scheduler.o
-
-process.o: process.c
-	$(CC) $(CFLAGS) process.c -o process.o
-
-clean:
-	rm -f *.elf *.o *.i

os/sync/spinlock.c

@@ -0,0 +1,34 @@
+// sync_primitives.c
+#include "spinlock.h"
+
+// Initialize the spinlock
+void spinlock_init(Spinlock *spinlock) {
+    spinlock->lock = 0; // Unlocked state
+}
+
+// Acquire the spinlock
+void spinlock_acquire(Spinlock *spinlock) {
+    int status;
+    do {
+        // Wait until the lock is available
+        do {
+            __asm__ volatile ("ldrex %0, [%1]"
+                              : "=&r" (status)
+                              : "r" (&spinlock->lock)
+                              : "memory");
+        } while (status != 0);
+
+        // Try to acquire the lock using strex
+        __asm__ volatile ("strex %0, %2, [%1]"
+                          : "=&r" (status)
+                          : "r" (&spinlock->lock), "r" (1)
+                          : "memory");
+    } while (status != 0); // Retry if strex failed
+}
+
+// Release the spinlock
+void spinlock_release(Spinlock *spinlock) {
+    // Use a memory barrier to ensure proper ordering
+    __asm__ volatile ("dmb" ::: "memory");
+    spinlock->lock = 0; // Release the lock
+}

os/sync/spinlock.h

@@ -0,0 +1,16 @@
+#ifndef SPINLOCK_H
+#define SPINLOCK_H
+
+#include <stdint.h>
+
+// Spinlock
+typedef struct {
+    volatile int lock;
+} Spinlock;
+
+void spinlock_init(Spinlock *spinlock);
+void spinlock_acquire(Spinlock *spinlock);
+void spinlock_release(Spinlock *spinlock);
+
+
+#endif