Update mult.py: branchless, compact

Author: daedalus

mult.py

@@ -1,15 +1,15 @@
 def mult(x, y):
     z = 0
     while y > 0:
-        z = z + x
-        y = y - 1
+        z += x
+        y -= 1
     return z
 
 
 def russian_peasant(x, y):
     z = 0
     while y > 0:
-        if y % 2 == 1: z = z + x
-        x = x << 1
-        y = y >> 1
-    return z 
+        z += x * (y & 1) 
+        x <<= 1
+        y >>= 1
+    return z