-
-#define mul_add_c(a,b,c0,c1,c2) { \
- BN_ULONG ta=(a),tb=(b); \
- t1 = ta * tb; \
- t2 = BN_UMULT_HIGH(ta,tb); \
- c0 += t1; t2 += (c0<t1)?1:0; \
- c1 += t2; c2 += (c1<t2)?1:0; \
- }
-
-#define mul_add_c2(a,b,c0,c1,c2) { \
- BN_ULONG ta=(a),tb=(b),t0; \
- t1 = BN_UMULT_HIGH(ta,tb); \
- t0 = ta * tb; \
- t2 = t1+t1; c2 += (t2<t1)?1:0; \
- t1 = t0+t0; t2 += (t1<t0)?1:0; \
- c0 += t1; t2 += (c0<t1)?1:0; \
- c1 += t2; c2 += (c1<t2)?1:0; \
- }
-
-#define sqr_add_c(a,i,c0,c1,c2) { \
- BN_ULONG ta=(a)[i]; \
- t1 = ta * ta; \
- t2 = BN_UMULT_HIGH(ta,ta); \
- c0 += t1; t2 += (c0<t1)?1:0; \
- c1 += t2; c2 += (c1<t2)?1:0; \
- }
+/*
+ * Keep in mind that additions to hi can not overflow, because
+ * the high word of a multiplication result cannot be all-ones.
+ */
+#define mul_add_c(a,b,c0,c1,c2) do { \
+ BN_ULONG ta = (a), tb = (b); \
+ BN_ULONG lo = ta * tb; \
+ BN_ULONG hi = BN_UMULT_HIGH(ta,tb); \
+ c0 += lo; hi += (c0<lo)?1:0; \
+ c1 += hi; c2 += (c1<hi)?1:0; \
+ } while(0)
+
+#define mul_add_c2(a,b,c0,c1,c2) do { \
+ BN_ULONG ta = (a), tb = (b), tt; \
+ BN_ULONG lo = ta * tb; \
+ BN_ULONG hi = BN_UMULT_HIGH(ta,tb); \
+ c0 += lo; tt = hi + ((c0<lo)?1:0); \
+ c1 += tt; c2 += (c1<tt)?1:0; \
+ c0 += lo; hi += (c0<lo)?1:0; \
+ c1 += hi; c2 += (c1<hi)?1:0; \
+ } while(0)
+
+#define sqr_add_c(a,i,c0,c1,c2) do { \
+ BN_ULONG ta = (a)[i]; \
+ BN_ULONG lo = ta * ta; \
+ BN_ULONG hi = BN_UMULT_HIGH(ta,ta); \
+ c0 += lo; hi += (c0<lo)?1:0; \
+ c1 += hi; c2 += (c1<hi)?1:0; \
+ } while(0)