fixed mistakes around semaphores

main.c

@@ -85,7 +85,7 @@ void task4(void) {
     static volatile int32_t t4;
 
     while (true) {
-        sem_post32(&t4, (int32_t)1);
+        atom_inc32(&t4, (int32_t)1);
         printf("task 4 %d %lu\r\n", g_uptime, t4);
         delay(3300);
     };

semaphore.c

@@ -12,10 +12,11 @@ void sem_init(sem_t* sem, int32_t value) {
 int32_t sem_wait(sem_t* sem) {
     //while(sem->value > 0);
     //sem->value--;
-    return sem_wait32(&(sem->value), (int32_t)1);
+    while (atom_dec32(&(sem->value), (int32_t)0) > 0);
+    return atom_dec32(&(sem->value), (int32_t)1);
 }
 
 int32_t sem_post(sem_t* sem) {
     //sem->value++;
-    return sem_post32(&(sem->value), (int32_t)1);
+    return atom_inc32(&(sem->value), (int32_t)1);
 }

semoper.S

@@ -3,10 +3,10 @@
 
 .text
 
-.globl  sem_post32
-.type   sem_post32, %function
+.globl  atom_inc32
+.type   atom_inc32, %function
 
-sem_post32:
+atom_inc32:
 1:
         ldrex           r2, [r0]
         add             r2, r2, r1
@@ -17,10 +17,10 @@ sem_post32:
         bx              lr
 
 
-.globl  sem_wait32
-.type   sem_wait32, %function
+.globl  atom_dec32
+.type   atom_dec32, %function
 
-sem_wait32:
+atom_dec32:
 1:
         ldrex           r2, [r0]
         sub             r2, r2, r1

semoper.h

@@ -7,7 +7,7 @@
 
 #include <stdint.h>
 
-int32_t sem_post32(volatile int32_t *addr, int32_t value);
-int32_t sem_wait32(volatile int32_t *addr, int32_t value);
+int32_t atom_inc32(volatile int32_t *addr, int32_t value);
+int32_t atom_dec32(volatile int32_t *addr, int32_t value);
 
 #endif