`((inst srawi x x 2)))
(inst mullw res x y))))
(frob unsigned-* "unsigned *" 40 unsigned-num unsigned-reg)
- (frob signed-* "unsigned *" 41 signed-num signed-reg)
+ (frob signed-* "signed *" 41 signed-num signed-reg)
(frob fixnum-* "fixnum *" 30 tagged-num any-reg))