module/language/assembly.scm

   1 ;;; Guile Virtual Machine Assembly
   2
   3 ;; Copyright (C) 2001 Free Software Foundation, Inc.
   4
   5 ;; This program is free software; you can redistribute it and/or modify
   6 ;; it under the terms of the GNU General Public License as published by
   7 ;; the Free Software Foundation; either version 2, or (at your option)
   8 ;; any later version.
   9 ;;
  10 ;; This program is distributed in the hope that it will be useful,
  11 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 ;; GNU General Public License for more details.
  14 ;;
  15 ;; You should have received a copy of the GNU General Public License
  16 ;; along with this program; see the file COPYING.  If not, write to
  17 ;; the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18 ;; Boston, MA 02111-1307, USA.
  19
  20 ;;; Code:
  21
  22 (define-module (language assembly)
  23   #:use-module (system base pmatch)
  24   #:use-module (system vm instruction)
  25   #:export (byte-length))
  26
  27 (define (byte-length x)
  28   (pmatch x
  29     (,label (guard (not (pair? label)))
  30      0)
  31     ;; instructions take one byte, hence the 1+.
  32     ((load-integer ,str)
  33      (1+ (string-length str)))
  34     ((load-number ,str)
  35      (1+ (string-length str)))
  36     ((load-string ,str)
  37      (1+ (string-length str)))
  38     ((load-symbol ,str)
  39      (1+ (string-length str)))
  40     ((load-keyword ,str)
  41      (1+ (string-length str)))
  42     ((define ,str)
  43      (1+ (string-length str)))
  44     ((assembly ,nargs ,nrest ,nlocs ,nexts ,labels ,len . ,code)
  45      ;; lengths of nargs, nrest, nlocs, nexts, len, and code, respectively
  46      (+ 1 1 1 1 4 len))
  47     ((,inst . _) (guard (>= (instruction-length inst) 0))
  48      (1+ (instruction-length inst)))
  49     (else (error "unknown instruction" x))))