-(define-vop (merge-bits)
- (:translate merge-bits)
- (:args (shift :scs (signed-reg unsigned-reg))
- (prev :scs (unsigned-reg))
- (next :scs (unsigned-reg)))
- (:arg-types tagged-num unsigned-num unsigned-num)
- (:temporary (:scs (unsigned-reg) :to (:result 0)) temp)
- (:temporary (:scs (unsigned-reg) :to (:result 0) :target result) res)
- (:results (result :scs (unsigned-reg)))
- (:result-types unsigned-num)
- (:policy :fast-safe)
- (:generator 4
- (let ((done (gen-label)))
- (inst cmp shift)
- (inst b :eq done)
- (inst srl res next shift)
- (inst sub temp zero-tn shift)
- (inst sll temp prev temp)
- (inst or res temp)
- (emit-label done)
- (move result res))))