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;;; Guile VM assembler
;; Copyright (C) 2001, 2009, 2010 Free Software Foundation, Inc.
;;;; This library is free software; you can redistribute it and/or
;;;; modify it under the terms of the GNU Lesser General Public
;;;; License as published by the Free Software Foundation; either
;;;; version 3 of the License, or (at your option) any later version.
;;;;
;;;; This library 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
;;;; Lesser General Public License for more details.
;;;;
;;;; You should have received a copy of the GNU Lesser General Public
;;;; License along with this library; if not, write to the Free Software
;;;; Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
;;; Code:
(define-module (language assembly compile-bytecode)
#:use-module (system base pmatch)
#:use-module (language assembly)
#:use-module (system vm instruction)
#:use-module (srfi srfi-4)
#:use-module (rnrs bytevectors)
#:use-module (ice-9 binary-ports)
#:use-module ((srfi srfi-1) #:select (fold))
#:use-module ((srfi srfi-26) #:select (cut))
#:export (compile-bytecode))
;; Gross.
(define (port-position port)
(seek port 0 SEEK_CUR))
(define (compile-bytecode assembly env . opts)
(pmatch assembly
((load-program . _)
(call-with-values open-bytevector-output-port
(lambda (port get-bytevector)
;; Don't emit the `load-program' byte.
(write-bytecode assembly port '() 0 #f)
(values (get-bytevector) env env))))
(else (error "bad assembly" assembly))))
(define (write-bytecode asm port labels address emit-opcode?)
;; Write ASM's bytecode to PORT, a (binary) output port. If EMIT-OPCODE? is
;; false, don't emit bytecode for the first opcode encountered. Assume code
;; starts at ADDRESS (an integer). LABELS is assumed to be an alist mapping
;; labels to addresses.
(define u32-bv (make-bytevector 4))
(define write-byte (cut put-u8 port <>))
(define get-addr
(let ((start (port-position port)))
(lambda ()
(+ address (- (port-position port) start)))))
(define (write-latin1-string s)
(write-loader-len (string-length s))
(string-for-each (lambda (c) (write-byte (char->integer c))) s))
(define (write-int24-be x)
(bytevector-s32-set! u32-bv 0 x (endianness big))
(put-bytevector port u32-bv 1 3))
(define (write-uint32-be x)
(bytevector-u32-set! u32-bv 0 x (endianness big))
(put-bytevector port u32-bv))
(define (write-uint32 x)
(bytevector-u32-native-set! u32-bv 0 x)
(put-bytevector port u32-bv))
(define (write-wide-string s)
(write-loader-len (* 4 (string-length s)))
(put-bytevector port (string->utf32 s (native-endianness))))
(define (write-loader-len len)
(write-byte (ash len -16))
(write-byte (logand (ash len -8) 255))
(write-byte (logand len 255)))
(define (write-bytevector bv)
(write-loader-len (bytevector-length bv))
(put-bytevector port bv))
(define (write-break label)
(let ((offset (- (assq-ref labels label) (+ (get-addr) 3))))
(cond ((>= offset (ash 1 23)) (error "jump too far forward" offset))
((< offset (- (ash 1 23))) (error "jump too far backwards" offset))
(else (write-int24-be offset)))))
(let ((inst (car asm))
(args (cdr asm)))
(let ((opcode (instruction->opcode inst))
(len (instruction-length inst)))
(if emit-opcode?
(write-byte opcode))
(pmatch asm
((load-program ,labels ,length ,meta . ,code)
(write-uint32 length)
(write-uint32 (if meta (1- (byte-length meta)) 0))
(fold (lambda (asm address)
(let ((start (port-position port)))
(write-bytecode asm port labels address #t)
(+ address (- (port-position port) start))))
0
code)
(if meta
;; Don't emit the `load-program' byte for metadata. Note that
;; META's bytecode meets the alignment requirements of
;; `scm_objcode', thanks to the alignment computed in `(language
;; assembly)'.
(write-bytecode meta port '() 0 #f)))
((make-char32 ,x) (write-uint32-be x))
((load-number ,str) (write-latin1-string str))
((load-string ,str) (write-latin1-string str))
((load-wide-string ,str) (write-wide-string str))
((load-symbol ,str) (write-latin1-string str))
((load-array ,bv) (write-bytevector bv))
((br ,l) (write-break l))
((br-if ,l) (write-break l))
((br-if-not ,l) (write-break l))
((br-if-eq ,l) (write-break l))
((br-if-not-eq ,l) (write-break l))
((br-if-null ,l) (write-break l))
((br-if-not-null ,l) (write-break l))
((br-if-nargs-ne ,hi ,lo ,l) (write-byte hi) (write-byte lo) (write-break l))
((br-if-nargs-lt ,hi ,lo ,l) (write-byte hi) (write-byte lo) (write-break l))
((br-if-nargs-gt ,hi ,lo ,l) (write-byte hi) (write-byte lo) (write-break l))
((mv-call ,n ,l) (write-byte n) (write-break l))
((prompt ,escape-only? ,l) (write-byte escape-only?) (write-break l))
(else
(cond
((< (instruction-length inst) 0)
(error "unhanded variable-length instruction" asm))
((not (= (length args) len))
(error "bad number of args to instruction" asm len))
(else
(for-each write-byte args))))))))
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