;;;; the machine-specific support routines needed by the file assembler

;;;; 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")

(defun generate-call-sequence (name style vop options)
  (declare (ignore options))
  (ecase style
    ((:none :raw)
     (let ((fixup-address (make-symbol "FIXUP-ADDRESS")))
       (values
        `((let ((,fixup-address (gen-label)))
            ,@(if (eq style :none)
                  `((inst load-from-label pc-tn lr-tn ,fixup-address))
                  `((inst load-from-label lr-tn lr-tn ,fixup-address)
                    (inst blx lr-tn)))
            (assemble (:elsewhere ,vop)
              (emit-label ,fixup-address)
              (inst word (make-fixup ',name :assembly-routine)))))
        nil)))
    #+(or)
    (:full-call
     (let ((temp (make-symbol "TEMP"))
           (jump (make-symbol "JUMP"))
           (nfp-save (make-symbol "NFP-SAVE"))
           (lra (make-symbol "LRA")))
       (values
        `((let ((lra-label (gen-label))
                (cur-nfp (current-nfp-tn ,vop)))
            (when cur-nfp
              (store-stack-tn ,nfp-save cur-nfp))
            (inst compute-lra-from-code ,lra code-tn lra-label ,temp)
            (note-next-instruction ,vop :call-site)
            (inst lr ,jump (make-fixup ',name :assembly-routine))
            (inst mtlr ,jump)
            (inst blr)
            (emit-return-pc lra-label)
            (note-this-location ,vop :single-value-return)
            (without-scheduling ()
              (move csp-tn ocfp-tn)
              (inst nop))
            (inst compute-code-from-lra code-tn lra-tn
                  lra-label ,temp)
            (when cur-nfp
              (load-stack-tn cur-nfp ,nfp-save))))
        `((:temporary (:scs (non-descriptor-reg) :from (:eval 0) :to (:eval 1))
                      ,temp)
          (:temporary (:sc descriptor-reg :offset lra-offset
                           :from (:eval 0) :to (:eval 1))
                      ,lra)
          (:temporary (:scs (control-stack) :offset nfp-save-offset)
                      ,nfp-save)
          (:temporary (:sc any-reg) ,jump)
          (:save-p :compute-only)))))))

(defun generate-return-sequence (style)
  (ecase style
    (:raw
     `((inst bx lr-tn)))
    #+(or)
    (:full-call
     `((lisp-return (make-random-tn :kind :normal
                                    :sc (sc-or-lose 'descriptor-reg )
                                    :offset lra-offset)
                    (make-random-tn :kind :normal
                                    :sc (sc-or-lose 'interior-reg )
                                    :offset lip-offset)
                    :offset 2)))
    (:none)))