src/assembly/x86/support.lisp

   1 ;;;; This software is part of the SBCL system. See the README file for
   2 ;;;; more information.
   3 ;;;;
   4 ;;;; This software is derived from the CMU CL system, which was
   5 ;;;; written at Carnegie Mellon University and released into the
   6 ;;;; public domain. The software is in the public domain and is
   7 ;;;; provided with absolutely no warranty. See the COPYING and CREDITS
   8 ;;;; files for more information.
   9
  10 (in-package "SB!VM")
  11
  12 ;;; The :full-call assembly-routines must use the same full-call
  13 ;;; unknown-values return convention as a normal call, as some
  14 ;;; of the routines will tail-chain to a static-function. The
  15 ;;; routines themselves, however, take all of their arguments
  16 ;;; in registers (this will typically be one or two arguments,
  17 ;;; and is one of the lower bounds on the number of argument-
  18 ;;; passing registers), and thus don't need a call frame, which
  19 ;;; simplifies things for the normal call/return case. When it
  20 ;;; is neccessary for one of the assembly-functions to call a
  21 ;;; static-function it will construct the required call frame.
  22 ;;; Also, none of the assembly-routines return other than one
  23 ;;; value, which again simplifies the return path.
  24 ;;;    -- AB, 2006/Feb/05.
  25
  26 (!def-vm-support-routine generate-call-sequence (name style vop)
  27   (ecase style
  28     ((:raw :none)
  29      (values
  30       `((inst call (make-fixup ',name :assembly-routine)))
  31       nil))
  32     (:full-call
  33      (values
  34       `((note-this-location ,vop :call-site)
  35         (inst call (make-fixup ',name :assembly-routine))
  36         (note-this-location ,vop :single-value-return)
  37         (cond
  38           ((member :cmov *backend-subfeatures*)
  39            (inst cmov :c esp-tn ebx-tn))
  40           (t
  41            (let ((single-value (gen-label)))
  42              (inst jmp :nc single-value)
  43              (move esp-tn ebx-tn)
  44              (emit-label single-value)))))
  45       '((:save-p :compute-only))))))
  46
  47 (!def-vm-support-routine generate-return-sequence (style)
  48   (ecase style
  49     (:raw
  50      `(inst ret))
  51     (:full-call
  52      `((inst clc)
  53        (inst ret)))
  54     (:none)))