pred.lisp

来自「开源跨平台Lisp编译器」· LISP 代码 · 共 32 行

(in-package "SB!VM")


;;;; The Branch VOP.

;;; The unconditional branch, emitted when we can't drop through to the desired
;;; destination.  Dest is the continuation we transfer control to.
;;;
(define-vop (branch)
  (:info dest)
  (:generator 5
    (inst b dest)
    (inst nop)))


;;;; Conditional VOPs:

(define-vop (if-eq)
  (:args (x :scs (any-reg descriptor-reg zero null))
         (y :scs (any-reg descriptor-reg zero null)))
  (:conditional)
  (:info target not-p)
  (:policy :fast-safe)
  (:translate eq)
  (:generator 3
    (if not-p
        (inst bne x y target)
        (inst beq x y target))
    (inst nop)))