;;;; x86 VM definitions of various system hacking operations

;;;; This software is part of the SBCL system. See the README file for
;;;; more information.
;;;;
;;;; This software is derived from the CMU CL system, which was
;;;; written at Carnegie Mellon University and released into the
;;;; public domain. The software is in the public domain and is
;;;; provided with absolutely no warranty. See the COPYING and CREDITS
;;;; files for more information.

(in-package "SB!VM")

;;;; type frobbing VOPs

(define-vop (lowtag-of)
  (:translate lowtag-of)
  (:policy :fast-safe)
  (:args (object :scs (any-reg descriptor-reg control-stack)
                 :target result))
  (:results (result :scs (unsigned-reg)))
  (:result-types positive-fixnum)
  (:generator 1
    (move result object)
    (inst and result lowtag-mask)))

(define-vop (widetag-of)
  (:translate widetag-of)
  (:policy :fast-safe)
  (:args (object :scs (descriptor-reg)))
  (:temporary (:sc unsigned-reg :offset eax-offset :to (:result 0)) eax)
  (:results (result :scs (unsigned-reg)))
  (:result-types positive-fixnum)
  (:generator 6
    (inst mov eax object)
    (inst and al-tn lowtag-mask)
    (inst cmp al-tn other-pointer-lowtag)
    (inst jmp :e other-ptr)
    (inst cmp al-tn fun-pointer-lowtag)
    (inst jmp :e function-ptr)

    ;; Pick off structures and list pointers.
    (inst test al-tn 1)
    (inst jmp :ne done)

    ;; Pick off fixnums.
    (inst and al-tn 3)
    (inst jmp :e done)

    ;; must be an other immediate
    (inst mov eax object)
    (inst jmp done)

    FUNCTION-PTR
    (load-type al-tn object (- fun-pointer-lowtag))
    (inst jmp done)

    OTHER-PTR
    (load-type al-tn object (- other-pointer-lowtag))

    DONE
    (inst movzx result al-tn)))

(define-vop (fun-subtype)
  (:translate fun-subtype)
  (:policy :fast-safe)
  (:args (function :scs (descriptor-reg)))
  (:temporary (:sc byte-reg :from (:eval 0) :to (:eval 1)) temp)
  (:results (result :scs (unsigned-reg)))
  (:result-types positive-fixnum)
  (:generator 6
    (load-type temp function (- fun-pointer-lowtag))
    (inst movzx result temp)))

(define-vop (set-fun-subtype)
  (:translate (setf fun-subtype))
  (:policy :fast-safe)
  (:args (type :scs (unsigned-reg) :target eax)
         (function :scs (descriptor-reg)))
  (:arg-types positive-fixnum *)
  (:temporary (:sc unsigned-reg :offset eax-offset :from (:argument 0)
                   :to (:result 0) :target result)
              eax)
  (:results (result :scs (unsigned-reg)))
  (:result-types positive-fixnum)
  (:generator 6
    (move eax type)
    (inst mov
          (make-ea :byte :base function :disp (- fun-pointer-lowtag))
          al-tn)
    (move result eax)))

(define-vop (get-header-data)
  (:translate get-header-data)
  (:policy :fast-safe)
  (:args (x :scs (descriptor-reg)))
  (:results (res :scs (unsigned-reg)))
  (:result-types positive-fixnum)
  (:generator 6
    (loadw res x 0 other-pointer-lowtag)
    (inst shr res n-widetag-bits)))

(define-vop (get-closure-length)
  (:translate get-closure-length)
  (:policy :fast-safe)
  (:args (x :scs (descriptor-reg)))
  (:results (res :scs (unsigned-reg)))
  (:result-types positive-fixnum)
  (:generator 6
    (loadw res x 0 fun-pointer-lowtag)
    (inst shr res n-widetag-bits)))

(define-vop (set-header-data)
  (:translate set-header-data)
  (:policy :fast-safe)
  (:args (x :scs (descriptor-reg) :target res :to (:result 0))
         (data :scs (any-reg) :target eax))
  (:arg-types * positive-fixnum)
  (:results (res :scs (descriptor-reg)))
  (:temporary (:sc unsigned-reg :offset eax-offset
                   :from (:argument 1) :to (:result 0)) eax)
  (:generator 6
    (move eax data)
    (inst shl eax (- n-widetag-bits 2))
    (inst mov al-tn (make-ea :byte :base x :disp (- other-pointer-lowtag)))
    (storew eax x 0 other-pointer-lowtag)
    (move res x)))

(define-vop (make-fixnum)
  (:args (ptr :scs (any-reg descriptor-reg) :target res))
  (:results (res :scs (any-reg descriptor-reg)))
  (:generator 1
    ;; Some code (the hash table code) depends on this returning a
    ;; positive number so make sure it does.
    (move res ptr)
    (inst shl res 3)
    (inst shr res 1)))

(define-vop (make-other-immediate-type)
  (:args (val :scs (any-reg descriptor-reg) :target res)
         (type :scs (unsigned-reg immediate)))
  (:results (res :scs (any-reg descriptor-reg) :from (:argument 0)))
  (:generator 2
    (move res val)
    (inst shl res (- n-widetag-bits 2))
    (inst or res (sc-case type
                   (unsigned-reg type)
                   (immediate (tn-value type))))))

;;;; allocation

(define-vop (dynamic-space-free-pointer)
  (:results (int :scs (sap-reg)))
  (:result-types system-area-pointer)
  (:translate dynamic-space-free-pointer)
  (:policy :fast-safe)
  (:generator 1
    (load-symbol-value int *allocation-pointer*)))

(define-vop (binding-stack-pointer-sap)
  (:results (int :scs (sap-reg)))
  (:result-types system-area-pointer)
  (:translate binding-stack-pointer-sap)
  (:policy :fast-safe)
  (:generator 1
    (load-binding-stack-pointer int)))

(defknown (setf binding-stack-pointer-sap)
    (system-area-pointer) system-area-pointer ())

(define-vop (set-binding-stack-pointer-sap)
  (:args (new-value :scs (sap-reg) :target int))
  (:arg-types system-area-pointer)
  (:results (int :scs (sap-reg)))
  (:result-types system-area-pointer)
  (:translate (setf binding-stack-pointer-sap))
  (:policy :fast-safe)
  (:generator 1
    (store-binding-stack-pointer new-value)
    (move int new-value)))

(define-vop (control-stack-pointer-sap)
  (:results (int :scs (sap-reg)))
  (:result-types system-area-pointer)
  (:translate control-stack-pointer-sap)
  (:policy :fast-safe)
  (:generator 1
    (move int esp-tn)))

;;;; code object frobbing

(define-vop (code-instructions)
  (:translate code-instructions)
  (:policy :fast-safe)
  (:args (code :scs (descriptor-reg) :to (:result 0)))
  (:results (sap :scs (sap-reg) :from (:argument 0)))
  (:result-types system-area-pointer)
  (:generator 10
    (loadw sap code 0 other-pointer-lowtag)
    (inst shr sap n-widetag-bits)
    (inst lea sap (make-ea :byte :base code :index sap :scale 4
                           :disp (- other-pointer-lowtag)))))

(define-vop (compute-fun)
  (:args (code :scs (descriptor-reg) :to (:result 0))
         (offset :scs (signed-reg unsigned-reg) :to (:result 0)))
  (:arg-types * positive-fixnum)
  (:results (func :scs (descriptor-reg) :from (:argument 0)))
  (:generator 10
    (loadw func code 0 other-pointer-lowtag)
    (inst shr func n-widetag-bits)
    (inst lea func
          (make-ea :byte :base offset :index func :scale 4
                   :disp (- fun-pointer-lowtag other-pointer-lowtag)))
    (inst add func code)))

(define-vop (%simple-fun-self)
  (:policy :fast-safe)
  (:translate %simple-fun-self)
  (:args (function :scs (descriptor-reg)))
  (:results (result :scs (descriptor-reg)))
  (:generator 3
    (loadw result function simple-fun-self-slot fun-pointer-lowtag)
    (inst lea result
          (make-ea :byte :base result
                   :disp (- fun-pointer-lowtag
                            (* simple-fun-code-offset n-word-bytes))))))

;;; The closure function slot is a pointer to raw code on X86 instead
;;; of a pointer to the code function object itself. This VOP is used
;;; to reference the function object given the closure object.
(define-source-transform %closure-fun (closure)
  `(%simple-fun-self ,closure))

(define-vop (%set-fun-self)
  (:policy :fast-safe)
  (:translate (setf %simple-fun-self))
  (:args (new-self :scs (descriptor-reg) :target result :to :result)
         (function :scs (descriptor-reg) :to :result))
  (:temporary (:sc any-reg :from (:argument 0) :to :result) temp)
  (:results (result :scs (descriptor-reg)))
  (:generator 3
    (inst lea temp
          (make-ea :byte :base new-self
                   :disp (- (ash simple-fun-code-offset word-shift)
                            fun-pointer-lowtag)))
    (storew temp function simple-fun-self-slot fun-pointer-lowtag)
    (move result new-self)))

;;;; other miscellaneous VOPs

(defknown sb!unix::receive-pending-interrupt () (values))
(define-vop (sb!unix::receive-pending-interrupt)
  (:policy :fast-safe)
  (:translate sb!unix::receive-pending-interrupt)
  (:generator 1
    (inst break pending-interrupt-trap)))

#!+sb-thread
(defknown current-thread-offset-sap ((unsigned-byte 32))
  system-area-pointer (flushable))

#!+sb-thread
(define-vop (current-thread-offset-sap)
  (:results (sap :scs (sap-reg)))
  (:result-types system-area-pointer)
  (:translate current-thread-offset-sap)
  (:args (n :scs (unsigned-reg) :target sap))
  (:arg-types unsigned-num)
  (:policy :fast-safe)
  (:generator 2
    (inst fs-segment-prefix)
    (inst mov sap (make-ea :dword :disp 0 :index n :scale 4))))

(define-vop (halt)
  (:generator 1
    (inst break halt-trap)))

(defknown float-wait () (values))
(define-vop (float-wait)
  (:policy :fast-safe)
  (:translate float-wait)
  (:vop-var vop)
  (:save-p :compute-only)
  (:generator 1
    (note-next-instruction vop :internal-error)
    (inst wait)))

;;;; dynamic vop count collection support

#!+sb-dyncount
(define-vop (count-me)
  (:args (count-vector :scs (descriptor-reg)))
  (:info index)
  (:generator 0
    (inst inc (make-ea :dword :base count-vector
                       :disp (- (* (+ vector-data-offset index) n-word-bytes)
                                other-pointer-lowtag)))))