mes/elf.mes

;;; -*-scheme-*-

;;; Mes --- Maxwell Equations of Software
;;; Copyright © 2016 Jan Nieuwenhuizen <janneke@gnu.org>
;;;
;;; scm.mes: This file is part of Mes.
;;;
;;; Mes is free software; you can redistribute it and/or modify it
;;; under the terms of the GNU General Public License as published by
;;; the Free Software Foundation; either version 3 of the License, or (at
;;; your option) any later version.
;;;
;;; Mes is distributed in the hope that it will be useful, but
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;;; GNU General Public License for more details.
;;;
;;; You should have received a copy of the GNU General Public License
;;; along with Mes.  If not, see <http://www.gnu.org/licenses/>.

(define (i386:puts data length)
  `(
     #xba ,@(int->bv32 length)      ;; mov    $0xe,%edx
          #xb9 ,@(int->bv32 data)        ;; mov    $data,%ecx
          #xbb #x01 #x00 #x00 #x00       ;; mov    $0x1,%ebx
          #xb8 #x04 #x00 #x00 #x00       ;; mov    $0x4,%eax
          #xcd #x80                      ;; int    $0x80
          ))

(define (i386:exit code)
  `(
    #xbb ,@(int->bv32 code)        ;; mov    $code,%ebx
         #xb8 #x01 #x00 #x00 #x00       ;; mov    $0x1,%eax
         #xcd #x80                      ;; int    $0x80
         ))

(define (i386:for start test step statement)
`(

  ;;   b:
  #x89 #xe5                	;; mov    %esp,%ebp
       ;;21:
       #xc7 #x45 #xf4 ,@(int->bv32 start) ;;	movl   $start,-0xc(%ebp)
       ;;28:
       #xeb ,(+ (length statement) 9) ;;x14	jmp    3e <main+0x3e>
       ;;2a:
       ;;#x83 #xec #x0c             ;;	sub    $0xc,%esp
       
       ;;   9:
       #x55   ;;                	push   %ebp
       
       ,@statement
       #x5d   ;;                	pop   %ebp
       ;;2d:
 ;;;;;;#x68 #x09 #x00 #x00 #x00       ;;	push   $0x9
       ;;32:
 ;;;;;;#xe8 #xfc #xff #xff #xff       ;;	call   33 <main+0x33>
       ;;37:
 ;;;;;;#x83 #xc4 #x10             ;;	add    $0x10,%esp
       ;;3a:
       ;;;;#x83 #x45 #xf4 ,step          ;;	addl   $step,-0xc(%ebp)
       ;;3e:
       ;;;;#x83 #x7d #xf4 ,test          ;;	cmpl   $test,-0xc(%ebp)
       #x81 #x45 #xf4 ,@(int->bv32 step) 	;;addl   $step,-0xc(%ebp)
       #x81 #x7d #xf4 ,@(int->bv32 test) ;;cmpl   $0x7cff,-0xc(%ebp)
       ;;42:
       ;;;#x7e ,(- 0 (length statement) 18) ;;#xe6 ;;	jle    2a <main+0x2a>
       #x75 ,(- 0 (length statement) 18) ;;#xe6 ;;	jne    2a <main+0x2a>
))

(define data
  (string->list "Hello, world!\n"))

(define (text d)
  (append
   (i386:puts d (length data))
   (i386:for 0 3 1 (i386:puts (+ d 6) (- (length data) 6)))
   (i386:exit 0)
   ))

(define (write-any x) (write-char (if (char? x) x (integer->char x))))
(map write-any (make-elf text data))