--- pgp/src/idea.c	2018/04/24 16:43:48	1.1.1.6
+++ pgp/src/idea.c	2018/04/24 16:44:46	1.1.1.7
@@ -92,9 +92,9 @@ CONST static uint16
 	a = p >> 16;
 	return (b - a) + (b < a);
     } else if (a) {
-	return 1 - b;
-    } else {
 	return 1 - a;
+    } else {
+	return 1 - b;
     }
 }				/* mul */
 #endif				/* SMALL_CACHE */
@@ -200,9 +200,9 @@ static void ideaInvertKey(word16 const *
 
 /*
  * MUL(x,y) computes x = x*y, modulo 0x10001.  Requires two temps, 
- * t16 and t32.  x is modified, and must me a side-effect-free lvalue.
- * y may be anything, but unlike x, must be strictly 16 bits even if
- * low16() is #defined.
+ * t16 and t32.  x is modified, and must be a side-effect-free lvalue.
+ * y may be anything, but unlike x, must be strictly less than 65536 
+ * even if low16() is #defined.
  * All of these are equivalent - see which is faster on your machine
  */
 #ifdef SMALL_CACHE
@@ -210,8 +210,8 @@ static void ideaInvertKey(word16 const *
 #else				/* !SMALL_CACHE */
 #ifdef AVOID_JUMPS
 #define MUL(x,y) (x = low16(x-1), t16 = low16((y)-1), \
-		t32 = (word32)x*t16 + x + t16 + 1, x = low16(t32), \
-		t16 = t32>>16, x = (x-t16) + (x<t16) )
+		t32 = (word32)x*t16 + x + t16, x = low16(t32), \
+		t16 = t32>>16, x = (x-t16) + (x<t16) + 1)
 #else				/* !AVOID_JUMPS (default) */
 #define MUL(x,y) \
 	((t16 = (y)) ? \