src/code/sc-offset.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 ;;; SC-OFFSETs are needed by sparc-vm.lisp
  11
  12 (in-package "SB!C")
  13 \f
  14 ;;;; SC-OFFSETs
  15 ;;;;
  16 ;;;; We represent the place where some value is stored with a SC-OFFSET,
  17 ;;;; which is the SC number and offset encoded as an integer.
  18
  19 ;;;; FIXME: this layout is hardcoded in some .S files,
  20 ;;;; undefined_tramp in at least mips/ppc/sparc-assem.S uses it.
  21 ;;;; Ideally, it shouldn't be hardcoded.
  22 (defconstant-eqx sc-offset-scn-byte (byte 6 0) #'equalp)
  23 (defconstant-eqx sc-offset-offset-byte (byte 21 6) #'equalp)
  24 (def!type sc-offset () '(unsigned-byte 27))
  25
  26 (defmacro make-sc-offset (scn offset)
  27   `(dpb ,scn sc-offset-scn-byte
  28         (dpb ,offset sc-offset-offset-byte 0)))
  29
  30 (defmacro sc-offset-scn (sco) `(ldb sc-offset-scn-byte ,sco))
  31 (defmacro sc-offset-offset (sco) `(ldb sc-offset-offset-byte ,sco))