diff --git a/bacnet-stack/include/bits.h b/bacnet-stack/include/bits.h
index 55671e17..0e6357db 100644
--- a/bacnet-stack/include/bits.h
+++ b/bacnet-stack/include/bits.h
@@ -70,4 +70,16 @@
 #define BIT30     (0x40000000UL)
 #define BIT31     (0x80000000UL)
 
+/* a=register, b=bit number to act upon 0-n */
+#define BIT_SET(a,b) ((a) |= (1<<(b)))
+#define BIT_CLEAR(a,b) ((a) &= ~(1<<(b)))
+#define BIT_FLIP(a,b) ((a) ^= (1<<(b)))
+#define BIT_CHECK(a,b) ((a) & (1<<(b)))
+
+/* x=target variable, y=mask */
+#define BITMASK_SET(x,y) ((x) |= (y))
+#define BITMASK_CLEAR(x,y) ((x) &= (~(y)))
+#define BITMASK_FLIP(x,y) ((x) ^= (y))
+#define BITMASK_CHECK(x,y) ((x) & (y))
+
 #endif