;; optional fields
(imm))
+;;; reg-no-width with #x0f prefix
+(sb!disassem:define-instruction-format (ext-reg-no-width 16
+ :default-printer '(:name :tab reg))
+ (prefix :field (byte 8 0) :value #b00001111)
+ (op :field (byte 5 11))
+ (reg :field (byte 3 8) :type 'reg))
+
;;; Same as reg/mem, but with a prefix of #b00001111
(sb!disassem:define-instruction-format (ext-reg/mem 24
:default-printer '(:name :tab reg/mem))
(emit-byte segment #b11010100)
(emit-byte segment #b00001010)))
+(define-instruction bswap (segment dst)
+ (:printer ext-reg-no-width ((op #b11001)))
+ (:emitter
+ (emit-byte segment #x0f)
+ (emit-byte-with-reg segment #b11001 (reg-tn-encoding dst))))
+
;;; CBW -- Convert Byte to Word. AX <- sign_xtnd(AL)
(define-instruction cbw (segment)
(:printer two-bytes ((op '(#b01100110 #b10011000))))
(define-instruction fxch (segment source)
(:printer floating-point-fp ((op '(#b001 #b001))))
(:emitter
- (unless (and (tn-p source)
- (eq (sb-name (sc-sb (tn-sc source))) 'float-registers))
- (cl:break))
+ (aver (and (tn-p source)
+ (eq (sb-name (sc-sb (tn-sc source))) 'float-registers)))
(emit-byte segment #b11011001)
(emit-fp-op segment source #b001)))