Add Semaphore

Implement basic semaphore, no sem_post (yet)

nx/include/switch.h

@@ -25,6 +25,7 @@ extern "C" {
 #include "switch/kernel/rwlock.h"
 #include "switch/kernel/condvar.h"
 #include "switch/kernel/thread.h"
+#include "switch/kernel/semaphore.h"
 #include "switch/kernel/virtmem.h"
 #include "switch/kernel/detect.h"
 #include "switch/kernel/random.h"

nx/include/switch/kernel/semaphore.h

@@ -0,0 +1,29 @@
+// Copyright 2018 Kevoot
+
+#ifndef __SEMAPHORE_H
+#define __SEMAPHORE_H
+
+#include "mutex.h"
+
+#define SEM_DOWN false
+#define SEM_UP   true
+
+#define EBUSY 1
+
+typedef struct sem_t
+{
+    bool flag;
+    Mutex mutex;
+} sem_t;
+
+void sem_init(sem_t *);
+void sem_uninit(sem_t *);
+/* TODO */
+void set_post(sem_t *);
+void sem_up(sem_t *);
+void sem_down(sem_t *);
+void sem_wait(sem_t *);
+void sem_waitup(sem_t *);
+bool sem_isup(sem_t *);
+
+#endif

nx/source/kernel/semaphore.c

@@ -0,0 +1,58 @@
+// Copyright 2018 Kevoot
+#include "kernel/semaphore.h"
+#include "kernel/svc.h"
+
+void _priv_sem_wait(sem_t *sem, bool flag);
+
+void sem_down(sem_t *sem) {
+    mutexLock(&sem->mutex);
+    sem->flag = SEM_DOWN;
+    mutexUnlock(&sem->mutex);
+}
+
+void sem_init(sem_t *sem) {
+    sem->flag = SEM_DOWN;
+    mutexInit(&sem->mutex);
+}
+
+void sem_uninit(sem_t *sem) {
+    sem->flag = SEM_DOWN;
+}
+            
+void sem_up(sem_t *sem) {
+    mutexLock(&sem->mutex);
+    sem->flag = SEM_UP;
+    mutexUnlock(&sem->mutex);
+}
+
+void sem_wait(sem_t *sem) {
+    _priv_sem_wait(sem, SEM_DOWN);
+}
+
+void sem_waitup(sem_t *sem) {
+    _priv_sem_wait(sem, SEM_UP);
+}
+
+bool sem_isup(sem_t *sem) {
+    bool flag;
+
+    mutexLock(&sem->mutex);
+    flag = sem->flag;
+    mutexUnlock(&sem->mutex);
+
+    return flag;
+}
+
+void _priv_sem_wait(sem_t *sem, bool flag) {
+    while (true) {
+        mutexLock(&sem->mutex);
+        
+        if (sem->flag == flag) {
+            mutexUnlock(&sem->mutex);
+            break;
+        }
+
+        mutexUnlock(&sem->mutex);
+        svcSleepThread(1000000);
+    }
+}