1 files changed, 18 insertions, 7 deletions
diff --git a/c/src/exec/libcsupport/include/ringbuf.h b/c/src/exec/libcsupport/include/ringbuf.h
index b2494c1527..8c80aaf9c8 100644
--- a/c/src/exec/libcsupport/include/ringbuf.h
+++ b/c/src/exec/libcsupport/include/ringbuf.h
@@ -10,13 +10,13 @@
 #define __RINGBUF_H__
 
 #ifndef RINGBUF_QUEUE_LENGTH
-#define RINGBUF_QUEUE_LENGTH 200
+#define RINGBUF_QUEUE_LENGTH 128
 #endif
 
 typedef struct {
   char buffer[RINGBUF_QUEUE_LENGTH];
-  int  head;
-  int  tail;
+  volatile int  head;
+  volatile int  tail;
 } Ring_buffer_t;
 
 #define Ring_buffer_Initialize( _buffer ) \
@@ -27,16 +27,27 @@ typedef struct {
 #define Ring_buffer_Is_empty( _buffer ) \
    ( (_buffer)->head == (_buffer)->tail )
 
+#define Ring_buffer_Is_full( _buffer ) \
+   ( (_buffer)->head == ((_buffer)->tail + 1) % RINGBUF_QUEUE_LENGTH )
+
 #define Ring_buffer_Add_character( _buffer, _ch ) \
   do { \
-    (_buffer)->buffer[ (_buffer)->tail ] = (_ch); \
-    (_buffer)->tail = ((_buffer)->tail+1) % RINGBUF_QUEUE_LENGTH; \
+    rtems_unsigned32 isrlevel; \
+    \
+    rtems_interrupt_disable( isrlevel ); \
+      (_buffer)->tail = ((_buffer)->tail+1) % RINGBUF_QUEUE_LENGTH; \
+      (_buffer)->buffer[ (_buffer)->tail ] = (_ch); \
+    rtems_interrupt_enable( isrlevel ); \
   } while ( 0 ) 
 
 #define Ring_buffer_Remove_character( _buffer, _ch ) \
   do { \
-    (_ch) = (_buffer)->buffer[ (_buffer)->head ]; \
-    (_buffer)->head = ((_buffer)->head+1) % RINGBUF_QUEUE_LENGTH; \
+    rtems_unsigned32 isrlevel; \
+    \
+    rtems_interrupt_disable( isrlevel ); \
+      (_buffer)->head = ((_buffer)->head+1) % RINGBUF_QUEUE_LENGTH; \
+      (_ch) = (_buffer)->buffer[ (_buffer)->head ]; \
+    rtems_interrupt_enable( isrlevel ); \
   } while ( 0 ) 
 
 #endif