diff --git a/block-sha1/sha1.c b/block-sha1/sha1.c
index 10fd94d179..6f885c4333 100644
--- a/block-sha1/sha1.c
+++ b/block-sha1/sha1.c
@@ -100,8 +100,8 @@
  * Where do we get the source from? The first 16 iterations get it from
  * the input data, the next mix it from the 512-bit array.
  */
-#define SHA_SRC(t) get_be32((unsigned char *) block + t*4)
-#define SHA_MIX(t) SHA_ROL(W(t+13) ^ W(t+8) ^ W(t+2) ^ W(t), 1)
+#define SHA_SRC(t) get_be32((unsigned char *) block + (t)*4)
+#define SHA_MIX(t) SHA_ROL(W((t)+13) ^ W((t)+8) ^ W((t)+2) ^ W(t), 1);
 
 #define SHA_ROUND(t, input, fn, constant, A, B, C, D, E) do { \
 	unsigned int TEMP = input(t); setW(t, TEMP); \