From ededa698590344a0a926033be97ee21ee61ee1d7 Mon Sep 17 00:00:00 2001
From: Oleg Borodin <onborodin@gmail.com>
Date: Tue, 30 Aug 2022 19:42:30 +0200
Subject: [PATCH] fixed mistakes around semaphores

---
 main.c      |  2 +-
 semaphore.c |  5 +++--
 semoper.S   | 12 ++++++------
 semoper.h   |  4 ++--
 4 files changed, 12 insertions(+), 11 deletions(-)

diff --git a/main.c b/main.c
index 55b5668..d50c57d 100644
--- a/main.c
+++ b/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);
     };
diff --git a/semaphore.c b/semaphore.c
index a8e0032..df8ff1e 100644
--- a/semaphore.c
+++ b/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);
 }
diff --git a/semoper.S b/semoper.S
index 561f1f2..52d185d 100644
--- a/semoper.S
+++ b/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
diff --git a/semoper.h b/semoper.h
index 23d2d10..90563eb 100644
--- a/semoper.h
+++ b/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