(in-package "SB-ROTATE-BYTE") (define-vop (%32bit-rotate-byte/c)   (:policy :fast-safe)   (:translate %unsigned-32-rotate-byte)   (:note "inline 32-bit constant rotation")   (:info count)   (:args (integer :scs (sb-vm::unsigned-reg) :target res))   (:arg-types (:constant (integer -31 31)) sb-vm::unsigned-byte-32)   (:results (res :scs (sb-vm::unsigned-reg)))   (:result-types sb-vm::unsigned-byte-32)   (:generator 5     ;; the 0 case is an identity operation and should be    ;; DEFTRANSFORMed away.    (aver (not (= count 0)))     (move res integer)     (if (> count 0)         (inst rol res count)         (inst ror res (- count))))) (define-vop (%32bit-rotate-byte-fixnum/c)   (:policy :fast-safe)   (:translate %unsigned-32-rotate-byte)   (:note "inline 32-bit constant rotation")   (:info count)   (:args (integer :scs (sb-vm::any-reg) :target res))   (:arg-types (:constant (integer -31 31)) sb-vm::positive-fixnum)   (:results (res :scs (sb-vm::unsigned-reg)))   (:result-types sb-vm::unsigned-byte-32)   (:generator 5     (aver (not (= count 0)))     (inst mov res integer)     (cond       ;; FIXME: all these 2s should be n-fixnum-tag-bits.      ((= count 2))       ((> count 2) (inst rol res (- count 2)))       (t (inst ror res (- 2 count)))))) (macrolet ((def (name arg-type)              `(define-vop (,name)                (:policy :fast-safe)                (:translate %unsigned-32-rotate-byte)                (:note "inline 32-bit rotation")                (:args (count :scs (sb-vm::signed-reg) :target ecx)                       (integer :scs (sb-vm::unsigned-reg) :target res))                (:arg-types sb-vm::tagged-num ,arg-type)                (:temporary (:sc sb-vm::signed-reg :offset sb-vm::ecx-offset)                            ecx)                (:results (res :scs (sb-vm::unsigned-reg) :from :load))                (:result-types sb-vm::unsigned-byte-32)                (:generator 10                 (let ((label (gen-label))                       (end (gen-label)))                   (move res integer)                   (move ecx count)                   (inst cmp ecx 0)                   (inst jmp :ge label)                   (inst neg ecx)                   (inst ror res :cl)                   (inst jmp end)                   (emit-label label)                   (inst rol res :cl)                   (emit-label end))))))   (def %32bit-rotate-byte sb-vm::unsigned-byte-32)   ;; FIXME: it's not entirely clear to me why we need this second  ;; definition -- or rather, why the compiler isn't smart enough to  ;; MOVE a POSITIVE-FIXNUM argument to an UNSIGNED-BYTE-32 argument,  ;; and then go from there.  Still, not having it leads to scary  ;; compilation messages of the form:  ;;  ;;    unable to do inline 32-bit constant rotation (cost 5) because:  ;;    This shouldn't happen!  Bug?  ;;    argument types invalid  ;;    argument primitive types:  ;;  (SB-VM::POSITIVE-FIXNUM SB-VM::POSITIVE-FIXNUM)  ;;  ;; so better leave it in.  (def %32bit-rotate-byte-fixnum sb-vm::positive-fixnum))