Merge pull request #180 from Cleverking2003/master

OS_mutex

1 files changed, 95 insertions, 0 deletions

diff --git a/arm7/lib/src/OS_mutex.c b/arm7/lib/src/OS_mutex.c
new file mode 100644
index 00000000..7e9b05ec
--- /dev/null
+++ b/arm7/lib/src/OS_mutex.c
@@ -0,0 +1,95 @@
+#include "function_target.h"
+#include "OS_mutex.h"
+#include "OS_system.h"
+#include "OS_thread.h"
+
+ARM_FUNC void OS_InitMutex(OSMutex* mutex) {
+    OS_InitThreadQueue(&mutex->queue);
+    mutex->thread = NULL;
+    mutex->count = 0;
+}
+
+ARM_FUNC void OS_LockMutex(OSMutex* mutex) {
+    OSIntrMode mode;
+    OSThread* current;
+    
+    mode = OS_DisableInterrupts();
+    current = OS_GetCurrentThread();
+    while (1) {
+        OSThread* owner = mutex->thread;
+        if (owner == NULL) {
+            mutex->thread = current;
+            mutex->count++;
+            OSi_EnqueueTail(current, mutex);
+            break;
+        }
+        else if (owner == current) {
+            mutex->count++;
+            break;
+        }
+        else {
+            current->mutex = mutex;
+            OS_SleepThread(&mutex->queue);
+            current->mutex = NULL;
+        }
+    }
+    (void)OS_RestoreInterrupts(mode);
+}
+
+ARM_FUNC void OS_UnlockMutex(OSMutex* mutex) {
+    OSIntrMode mode;
+    OSThread* current;
+    
+    mode = OS_DisableInterrupts();
+    current = OS_GetCurrentThread();
+    if (mutex->thread == current) {
+        if (--mutex->count == 0) {
+            OSi_DequeueItem(current, mutex);
+            mutex->thread = NULL;
+            OS_WakeupThread(&mutex->queue);
+        }
+    }
+    (void)OS_RestoreInterrupts(mode);
+}
+
+ARM_FUNC void OSi_UnlockAllMutex(OSThread * thread) {
+    OSMutex * mutex;
+    while (thread->mutexQueue.head) {
+        mutex = OSi_RemoveMutexLinkFromQueue(&thread->mutexQueue);
+        mutex->count = 0;
+        mutex->thread = NULL;
+        OS_WakeupThread(&mutex->queue);
+    }
+}
+
+ARM_FUNC void OSi_EnqueueTail(OSThread * thread, OSMutex * mutex) {
+    OSMutex * tail = thread->mutexQueue.tail;
+    if (tail == NULL) {
+        thread->mutexQueue.head = mutex;
+    }
+    else {
+        tail->link.next = mutex;
+    }
+    mutex->link.prev = tail;
+    mutex->link.next = NULL;
+    thread->mutexQueue.tail = mutex;
+}
+
+ARM_FUNC void OSi_DequeueItem(OSThread * thread, OSMutex * mutex) {
+    OSMutex *next = mutex->link.next;
+    OSMutex *prev = mutex->link.prev;
+
+    if (next == NULL) {
+        thread->mutexQueue.tail = prev;
+    }
+    else {
+        next->link.prev = prev;
+    }
+
+    if (prev == NULL) {
+        thread->mutexQueue.head = next;
+    }
+    else {
+        prev->link.next = next;
+    }
+}