Update functions.c

functions.c

@@ -27,12 +27,12 @@
 #define htols(x)     __bswap_16(x)
 #endif
 
-#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0)
+#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", __LINE__, __FILE__, errno, strerror(errno)); } while(0)
 
 #define MAP_SIZE (32*1024UL)
 #define MAP_MASK (MAP_SIZE - 1)
 
-void write_bits(char *device_loc, char *address, unsigned int writeval)
+int write_bits(char *device_loc, char *address, unsigned int writeval)
 {
   char *device = strdup(device_loc);
   off_t target = strtoul(address, 0, 0);
@@ -41,15 +41,19 @@ void write_bits(char *device_loc, char *address, unsigned int writeval)
 
    /* open device */
   int fd = open(device_loc, O_RDWR | O_SYNC));
-  if ((fd == -1)
+  if ((fd == -1) {
     FATAL;
+    return -1;
+  }
   printf("character device %s opened.\n", device_loc);
   fflush(stdout);
   
   /* map one page */
   void *map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-  if (map_base == (void *)-1)
+  if (map_base == (void *)-1) {
     FATAL;
+    return -1;
+  }
   printf("Memory mapped at address %p.\n", map_base);
   fflush(stdout);
 
@@ -65,9 +69,10 @@ void write_bits(char *device_loc, char *address, unsigned int writeval)
     writeval = htoll(writeval);
     *((uint32_t *) virt_addr) = writeval;
   fflush(stdout);
+  return 0;
 };
 
-unsigned int read_bits(char *device_loc, char *address)
+int read_bits(char *device_loc, char *address, uint32_t *read_result)
 {
   char *device = strdup(device_loc);
   off_t target = strtoul(address, 0, 0);
@@ -76,15 +81,19 @@ unsigned int read_bits(char *device_loc, char *address)
 
    /* open device */
   int fd = open(device_loc, O_RDWR | O_SYNC));
-  if (( fd == -1)
+  if (( fd == -1){
     FATAL;
+    return -1;
+  }
   printf("character device %s opened.\n", device_loc);
   fflush(stdout);
 
   /* map one page */
   void *map_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
-  if (map_base == (void *)-1)
+  if (map_base == (void *)-1){
     FATAL;
+    return -1;
+  }
   printf("Memory mapped at address %p.\n", map_base);
   fflush(stdout);
 
@@ -92,17 +101,18 @@ unsigned int read_bits(char *device_loc, char *address)
   void *virt_addr = map_base + target;
 
   /* Read */
-  uint32_t read_result = *((uint32_t *) virt_addr);
-
+  uint32_t read_result_tmp = *((uint32_t *) virt_addr);
+  
   /* swap 32-bit endianess if host is not little-endian */
-  read_result = ltohl(read_result);
+  read_result_tmp = ltohl(read_result_tmp);
   printf
     ("Read 32-bit value at address 0x%08x (%p): 0x%08x\n",
       (unsigned int)target, virt_addr,
-      (unsigned int)read_result);
+      (unsigned int)read_result_tmp);
 
   fflush(stdout);
-  return (unsigned int)read_result;
+  *read_result = read_result_tmp;
+  return 0;
 };
 
 void printBits(unsigned int num){