scsh-0.5/scsh/static.scm.in

#!@prefix@/lib/scsh/scshvm \
-o @prefix@/lib/scsh/scshvm -h 8000000 -i @prefix@/lib/scsh/scsh.image -lm @prefix@/lib/scsh/vm/ps-interface.scm -lm @prefix@/lib/scsh/vm/interfaces.scm -lm @prefix@/lib/scsh/vm/package-defs.scm -lm @prefix@/lib/scsh/vm/s48-package-defs.scm -dm -m scsh-static-heap -e scsh-static-linker -s 
!#
;;; Package for Static heaps for the Scheme Shell
;;; Copyright (c) 1995 by Brian D. Carlstrom.

;;; based on Scheme48 implementation.
;;; Copyright (c) 1993, 1994 by Richard Kelsey and Jonathan Rees.

;;(define-structure heap-extra (export newspace-begin
;;			      heap-pointer
;;			      header-a-units
;;			      d-vector? 
;;			      stob-type)
;;  (open scheme heap)
;;  (begin
;;    (define (newspace-begin) *newspace-begin*)
;;    (define (heap-pointer) *hp*)))

(define-structure scsh-static-heap (export scsh-static-linker)
  (open scheme heap memory data stob struct
	heap-extra
	vm-architecture
	formats
	enumerated
	signals
	tables
	defrec-package
	scsh)
  (begin

    (define (scsh-static-linker argl)
      (if (not (= (length argl) 3))
	  (error "usage: ~a input-image-file output-executible-file" 
		 (car argl))
	  (let ((tempdir (or (getenv "TMPDIR")
			     "@TMPDIR@"))
		(cc-command   (or (getenv "CC")
				  "@CC@ @CFLAGS@"))
		(linker-flags (or (getenv "LDFLAGS")
				  "@LDFLAGS@"))
		(libraries    (or (getenv "LIBS")
				  "@LIBS@"))
		(infile (cadr argl))
		(outfile (caddr argl)))
	    (scsh-do-it infile tempdir outfile 
			cc-command linker-flags libraries)
	    (exit 0))))

    ;;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
    (define-record heap
      (length    0)
      (objects '())
      )
    ;;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
    (define (scsh-do-it infile tempdir outfile 
			cc-command linker-flags libraries)
      (let* ((temp-dir (format #f "~a/scsh~s" tempdir (pid)))
	     (prefix (string-append temp-dir "/static"))
	     (start (read-heap-image infile)))
	(receive (pure impure reloc externs)
	    (create-heaps-and-tables)
	  (if (file-exists? temp-dir)
	      (if (file-directory? temp-dir)
		  (with-cwd temp-dir
			    (map delete-file (directory-files temp-dir #t)))
		  (delete-file temp-dir)))
	  (create-directory temp-dir #o755 #t)
	  (with-cwd temp-dir
		    (write-c-header-file pure impure externs infile outfile prefix)
		    (write-c-image pure impure reloc externs prefix)
		    (write-main-c-file start reloc prefix)
		    (compile-c-files cc-command prefix))
	  (link-files cc-command linker-flags libraries outfile prefix)
	  )))


    (define debug #f)

    (define (vm-string->string x)
      (cond ((vm-string? x)
	     (let ((len (vm-string-length x)))
	       (let loop ((i 0) 
			  (l '()))
		 (cond ((= i len) 
			(list->string (reverse l)))
		       (else
			(loop (+ i 1) (cons (vm-string-ref x i) l)))))))
	    (else
	     (message x " is not a vm-string"))))

    (define (read-heap-image infile)
      (let ((bytes (file-info:size (file-info infile))))
	(init (inexact->exact (floor (* 1.1 bytes))) infile)))
					; XXX need little extra space for find-all-xs

    (define (create-heaps-and-tables)
      (let* ((n       (nchunks))
	     (  pure  (make-vector n))
	     (impure  (make-vector n))
	     (reloc   (make-vector n))
	     (externs (make-table   )))
	;; initialize to blanks
	(let loop ((i 0))
	  (cond ((not (= i n))
		 (vector-set!   pure i (make-heap ))
		 (vector-set! impure i (make-heap ))
		 (vector-set!  reloc i (make-table))
		 (loop (+ i 1)))))
	(scsh-for-each-stored-object
	 (lambda (chunk)
	   (format #t "Reading chunk number ~s" chunk))
	 (lambda (chunk x len)
	   (if debug
	       (write x))
	   (let* ((mutable (mutable? x))
		  (heap (vector-ref (if mutable impure pure) chunk)))
	     (table-set! (vector-ref reloc chunk) x (heap:length heap))
	     (set-heap:objects heap (cons x (heap:objects heap)))
	     (set-heap:length  heap (+ len  (heap:length  heap)))
	     (cond (debug
		    (display (if mutable "   mutable " " immutable "))
		    (cond ((d-vector? x)  (display " d-vector"))
			  ((vm-string? x) (display "vm-string"))
			  (else           (display " b-vector")))
		    (let ((m (heap:length (vector-ref impure chunk)))
			  (i (heap:length (vector-ref   pure chunk))))
		      (message " m" m "+i" i "=" (+ m i))))))
	   (if (= (header-type (stob-header x)) (enum stob external))
	       (table-set! externs 
			   (external-value x) 
			   (vm-string->string (external-name x))))
	   )
	 (lambda (chunk) 
	   (newline)))
	(let loop ((i 0))
	  (cond ((not (= i n))
		 (let ((p (vector-ref   pure i))
		       (i (vector-ref impure i)))
		   (set-heap:objects p (reverse (heap:objects p)))
		   (set-heap:objects i (reverse (heap:objects i))))
		 (loop (+ i 1)))))
	(values pure impure reloc externs)))

    (define (write-c-header-file pure impure externs infile outfile prefix)
      (message "Writing header file")
      (call-with-output-file (string-append prefix ".h")
	(lambda (port)
	  (format port "/* Static Heap File Automatically Generated~%")
	  (format port " * by   scsh/static.scm~%")
	  (format port " * from ~a~%" infile)
	  (format port " * to   ~a~%" outfile)
	  (format port " */~%")
	  (let ((n (nchunks)))
	    (do ((i 0 (+ i 1)))
		((= i n))
	      (format port "extern const long p~s[~s];~%" i 
		      (quotient (heap:length (vector-ref   pure i)) 4)))
	    (do ((i 0 (+ i 1)))
		((= i n))
	      (format port "extern long i~s[~s];~%" i
		      (quotient (heap:length (vector-ref impure i)) 4))))
	  (table-walk
	   (lambda (address name)
	     (format port "const extern ~a();~%" name))
	   externs)
	  )))

    (define (d-vector-for-each proc d-vector)
      (do ((i 0 (+ i 1)))
	  ((>= i (d-vector-length d-vector)))
	(proc (d-vector-ref d-vector i))))

    (define (write-c-image pure impure reloc externs prefix)
      (message "Writing   pure c files")
      (scsh-write-c-image   pure "p" "const " reloc externs prefix)
      (message "Writing impure c files")
      (scsh-write-c-image impure "i" ""       reloc externs prefix))

    (define (scsh-write-c-image heap name const reloc externs prefix)
      (let ((n (nchunks)))
	(let chunk-loop ((c 0))
	  (cond ((not (= c n))
		 (format #t "Writing ~a-~a~s.c~%" prefix name c)
		 (call-with-output-file 
		     (format #f "~a-~a~s.c" prefix name c)
		   (lambda (port)	     
		     (format port "#include \"~a.h\"~%" prefix)
		     (format port "~a long ~a~s[]={~%" const name c)
		     (let ((heap (vector-ref heap c)))
		       (let heap-loop ((l (heap:objects heap)))
			 (cond ((not (null? l))
				(scsh-emit-initializer (car l) reloc externs port)
				(heap-loop (cdr l))))))
		     (display "};" port)
		     (newline port)))
		 (chunk-loop (+ 1 c)))))))

    (define (write-main-c-file start reloc prefix)
      (let ((n (nchunks)))
	(call-with-output-file (string-append prefix ".c")
	  (lambda (port)
	    (format port "#include \"~a.h\"~%" prefix)
	    (format port "const long p_count = ~s;~%" n)
	    (format port "const long i_count = ~s;~%" n)
	    
	    (format port "const long * const p_areas[~s] = {" n)
	    (do ((i 0 (+ i 1)))
		((= i n))
	      (format port "(const long *) &p~s, " i))
	    (format port "};~%")

	    (format port "long * const i_areas[~s] = {" n)
	    (do ((i 0 (+ i 1)))
		((= i n))
	      (format port "(long *) &i~s, " i))
	    (format port "};~%")

	    (format port "const long p_sizes[~s] = {" n)
	    (do ((i 0 (+ i 1)))
		((= i n))
	      (format port "sizeof(p~s), " i))
	    (format port "};~%")

	    (format port "const long i_sizes[~s] = {" n)
	    (do ((i 0 (+ i 1)))
		((= i n))
	      (format port "sizeof(i~s), " i))
	    (format port "};~%")

	    (display "const long entry = " port)
	    (scsh-emit-descriptor start reloc port)
	    (write-char #\; port)
	    (newline port)))))

    (define (compile-c-files cc-command prefix)
      (let ((n (nchunks))
	    (cc (append (line->list cc-command) '(-c))))
	(message "Compiling main C file")
	(message (append cc (list (format #f "~a.c" prefix))))
	(run (,@(append cc (list (format #f "~a.c" prefix)))))
	(do ((i 0 (+ i 1)))
	    ((= i n))
	  (message "Compiling C file for   pure chunk " i)
	  (message (append cc (list (format #f "~a-p~s.c" prefix i))))
	  (run (,@(append cc 
			  (list (format #f "~a-p~s.c" prefix i)))))
	  (message "Compiling C file for impure chunk " i)
	  (message (append cc (list (format #f "~a-i~s.c" prefix i))))
	  (run (,@(append cc 
			  (list (format #f "~a-i~s.c" prefix i))))))))

    (define (link-files cc-command linker-flags libraries outfile prefix)
      (let ((n (nchunks))
	    (ld (append (line->list cc-command)
			(line->list linker-flags)
			`(-o ,outfile)))
	    (libs (line->list libraries)))
	(message "Linking executible")
	(message (append ld
			 (let loop ((i 0)
				    (l '()))
			   (cond ((not (= i n))
				  (loop (+ i 1)
					(cons 
					 (format #f "~a-i~s.o" prefix i)
					  (cons
					   (format #f "~a-p~s.o" prefix i)
					   l))))
				 (else 
				  (reverse 		
				   (cons 
				    (string-append prefix ".o")
				    l)))))
			 '("@prefix@/lib/scsh/libscshvm.a")
			 libs))
	(run (,@(append 
		 ld
		 (let loop ((i 0)
			    (l '()))
		   (cond ((not (= i n))
			  (loop (+ i 1)
				 (cons 
				  (format #f "~a-i~s.o" prefix i)
				  (cons
				   (format #f "~a-p~s.o" prefix i)
				   l))))
			  (else 
			   (reverse 		
			    (cons 
			     (string-append prefix ".o")
			     l)))))
		 '("@prefix@/lib/scsh/libscshvm.a")
		 libs)))))

    (define (scsh-emit-initializer x reloc externs port)
      (write-hex port (stob-header x))
      (cond ((d-vector? x)
	     (scsh-emit-d-vector-initializer x reloc port))
	    ((vm-string? x)
	     (scsh-emit-vm-string-initializer x port))
	    (else
	     (scsh-emit-b-vector-initializer x reloc externs port)))
      (if *comments?*
	  (begin (display " /* " port)
		 (writex x port)
		 (display " */" port)))
      (newline port))


    (define (scsh-emit-d-vector-initializer x reloc port)
      (let ((len (d-vector-length x)))
	(do ((i 0 (+ i 1)))
	    ((= i len))
	  (scsh-emit-descriptor (d-vector-ref x i) reloc port)
	  (write-char #\, port))))

    (define (scsh-emit-vm-string-initializer x port)
      (let* ((len (vm-string-length x))	; end is jawilson style hack
	     (end (- (cells->bytes (bytes->cells (+ len 1))) 4)))
	(do ((i 0 (+ i 4)))
	    ((= i end) 
	     (case (- len end)
	       ((0)
		(write-hex port 0))
	       ((1)
		(write-hex
		 port
		 (net-to-host-32 (arithmetic-shift 
				  (char->ascii (vm-string-ref x i)) 24))))
	       ((2)
		(write-hex 
		 port
		 (net-to-host-32 
		  (bitwise-ior
		   (arithmetic-shift
		    (char->ascii (vm-string-ref x i))       24)
		   (arithmetic-shift
		    (char->ascii (vm-string-ref x (+ i 1))) 16)))))
	       ((3)
		(write-hex
		 port
		 (net-to-host-32
		  (bitwise-ior
		   (bitwise-ior
		    (arithmetic-shift 
		     (char->ascii (vm-string-ref x i))       24)
		    (arithmetic-shift 
		     (char->ascii (vm-string-ref x (+ i 1))) 16))
		   (arithmetic-shift  
		    (char->ascii (vm-string-ref x (+ i 2)))  8)))))))
	  (write-hex port
		     (net-to-host-32 (bitwise-ior
				      (bitwise-ior
				       (arithmetic-shift 
					(char->ascii (vm-string-ref x i))       24)
				       (arithmetic-shift 
					(char->ascii (vm-string-ref x (+ i 1))) 16))
				      (bitwise-ior
				       (arithmetic-shift 
					(char->ascii (vm-string-ref x (+ i 2)))  8)
				       (char->ascii  (vm-string-ref x (+ i 3))))))
		     ))))

    (define (scsh-emit-b-vector-initializer x reloc externs port)
      (cond ((and (code-vector? x)
		  (table-ref externs x)) =>
		  (lambda (name)
		    (format port "(long) *~a," name)))
	    (else 
	     (let* ((len (b-vector-length x)) ;end is jawilson style hack
		    (end (- (cells->bytes (bytes->cells (+ len 1))) 4)))
	       (do ((i 0 (+ i 4)))
		   ((= i end)
		    (case (- len end)
		      ((1)
		       (write-hex
			port
			(net-to-host-32 (arithmetic-shift (b-vector-ref x i) 24))))
		      ((2)
		       (write-hex 
			port
			(net-to-host-32
			 (bitwise-ior
			  (arithmetic-shift (b-vector-ref x i)       24)
			  (arithmetic-shift (b-vector-ref x (+ i 1)) 16)))))
		      ((3)
		       (write-hex
			port
			(net-to-host-32
			 (bitwise-ior
			  (bitwise-ior
			   (arithmetic-shift (b-vector-ref x i)       24)
			   (arithmetic-shift (b-vector-ref x (+ i 1)) 16))
			  (arithmetic-shift  (b-vector-ref x (+ i 2))  8)))
			))))
		 (write-hex 
		  port
		  (net-to-host-32 (bitwise-ior
				   (bitwise-ior
				    (arithmetic-shift (b-vector-ref x i)       24)
				    (arithmetic-shift (b-vector-ref x (+ i 1)) 16))
				   (bitwise-ior
				    (arithmetic-shift (b-vector-ref x (+ i 2))  8)
				    (b-vector-ref x (+ i 3))))))))
	     )))

    (define (scsh-emit-descriptor x reloc port)
      (if (stob? x)
	  (let ((n (chunk-number x)))
	    (display "(long)(&" port)
	    (if (immutable? x)
		(display "p" port)
		(display "i" port))
	    (display n port)
	    (display "[" port)
	    (display (quotient (table-ref (vector-ref reloc n) x) 4) port)
	    (display "])+7" port))
	  (format port 
		  (if (negative? x) "-0x~a" "0x~a")
		  (number->string (abs x) 16))))

    (define (scsh-for-each-stored-object chunk-start proc chunk-end)
      (let ((limit (heap-pointer)))
	(let chunk-loop ((addr (newspace-begin))
			 (i 0)
			 (chunk (+ (newspace-begin) *chunk-size*)))
	  (if (addr< addr limit)
	      (begin (chunk-start i)
		     (let loop ((addr addr))
		       (if (and (addr< addr limit)
				(addr< addr chunk))
			   (let* ((d   (fetch addr))
				  (len (addr1+ (header-a-units d))))
			     (if (not (header? d))
				 (warn "heap is in an inconsistent state" d))
			     (proc i (address->stob-descriptor (addr1+ addr)) len)
			     (loop (addr+ addr len)))
			   (begin (chunk-end i)
				  (chunk-loop addr
					      (+ i 1)
					      (+ chunk *chunk-size*))))))))))

    (define (write-hex port x) 
      (format port 
	      (if (negative? x) "-0x~a," "0x~a,")
	      (number->string (abs x) 16)))

    ;; takes a string and break it into a list at whitespace
    ;; rewrite using scsh stuff?
    (define (line->list line)
      (let ((len (string-length line)))
	(let loop ((start 0)
		   (end 0)
		   (l '()))
	  (cond ((>= end len)
		 (if (= start end)
		     l
		     (append l (list (substring line start end)))))
		((and (= start end)
		      (or (char=? (string-ref line start) (ascii->char 32))
			  (char=? (string-ref line start) (ascii->char 9))))
		 (loop (+ 1 start) 
		       (+ 1 end) 
		       l))
		((or (char=? (string-ref line end) (ascii->char 32))
		     (char=? (string-ref line end) (ascii->char 9)))
		 (loop (+ 1 end) 
		       (+ 1 end) 
		       (append l (list (substring line start end)))))
		((< end len)
		 (loop start 
		       (+ 1 end)
		       l))
		(else (error "unexpected case in line->list"))))))

;;;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-
;;; Debugging
;;;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

    (define (bin n)
      (number->string n 2))

    (define (oct n)
      (number->string n 8))

    (define (dec n)
      (number->string n 10))

    (define (hex n)
      (number->string n 16))

;;-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-

    ; For example:
    ;   (do-it 100000 "~/s48/debug/little.image" "little-heap.c")
    ;
    ; The first argument to do-it should be somewhat larger than the size,
    ; in bytes, of the image file to be converted (which you can obtain with
    ; "ls -l").
    ;
    ; If the image contains 0-length stored objects, then the .c file will
    ; have to be compiled by gcc, since 0-length arrays aren't allowed in
    ; ANSI C.  This wouldn't be difficult to work around.
    
    (define *comments?* #f)
    
    ; 800,000 bytes => 200,000 words => at least 100,000 objects
    ;   50 chunks => 16,000 bytes per chunk => 2,000 objects per chunk
    (define *chunk-size* 10000)

    (define (do-it bytes infile outfile)
      (let ((start (init bytes infile)))
	(call-with-output-file outfile
	  (lambda (port)
	    (format port "#define D(x) (long)(&x)+7~%")
	    (format port "#define H unsigned long~%")
	    (emit-area-declarations "p" immutable? "const " port)
	    (emit-area-declarations "i" mutable? "" port)
	    (emit-area-initializers "p" immutable? "const " port)
	    (emit-area-initializers "i" mutable? "" port)
	    (display "const long entry = " port)
	    (emit-descriptor start port)
	    (write-char #\; port)
	    (newline port)))))

    (define (init bytes infile)
      (create-memory (quotient bytes 2) quiescent) ;Output of ls -l
      (initialize-heap (memory-begin) (memory-size))
      (let ((start (read-image infile 0)))
	(message (nchunks)
		 " chunks")
	start))

    (define (nchunks) (+ (chunk-number (heap-pointer)) 1))

					; emit struct declarations for areas

    (define (emit-area-declarations name in-area? const port)
      (for-each-stored-object
       (lambda (chunk)
	 (message name chunk " declaration")
	 (display "struct " port) (display name port) (display chunk port)
	 (display " {" port) (newline port))
       (lambda (x)
	 (if (in-area? x)
	     (emit-declaration x port)))
       (lambda (chunk)
	 (display "};" port)
	 (newline port)
	 (display const port)
	 (display "extern struct " port) (display name port) (display chunk port)
	 (write-char #\space port) (display name port) (display chunk port)
	 (write-char #\; port) (newline port)
	 chunk)))

    (define (emit-declaration x port)
      (display "  H x" port)
      (writex x port)
      (cond ((d-vector? x)
	     (display "; long d" port)
	     (writex x port)
	     (write-char #\[ port)
	     (write (d-vector-length x) port))
	    ((vm-string? x)
	     (display "; char d" port)
	     (writex x port)
	     (write-char #\[ port)
	     ;; Ensure alignment (thanks Ian)
	     (write (cells->bytes (bytes->cells (b-vector-length x)))
		    port))
	    (else
	     (display "; unsigned char d" port)
	     (writex x port)
	     (write-char #\[ port)
	     ;; Ensure alignment
	     (write (cells->bytes (bytes->cells (b-vector-length x)))
		    port)))
      (display "];" port)
      (if *comments?*
	  (begin (display " /* " port)
		 (display (enumerand->name (stob-type x) stob) port)
		 (display " */" port)))
      (newline port))

					; Emit initializers for areas

    (define (emit-area-initializers name in-area? const port)
      (for-each-stored-object
       (lambda (chunk)
	 (message name chunk " initializer")

	 (display const port)
	 (display "struct " port) (display name port) (write chunk port)
	 (write-char #\space port) (display name port) (write chunk port)
	 (display " =" port) (newline port)

	 (write-char #\{ port) (newline port))
       (lambda (x)
	 (if (in-area? x)
	     (emit-initializer x port)))
       (lambda (chunk)
	 (display "};" port) (newline port)))

      (let ((n (nchunks)))
	(format port "const long ~a_count = ~s;~%" name n)
	(format port "~a long * const ~a_areas[~s] = {" const name n)
	(do ((i 0 (+ i 1)))
	    ((= i n))
	  (format port "(~a long *)&~a~s, " const name i))
	(format port "};~%const long ~a_sizes[~s] = {" name n)
	(do ((i 0 (+ i 1)))
	    ((= i n))
	  (format port "sizeof(~a~s), " name i))
	(format port "};~%")))


    (define (message . stuff)
      (for-each display stuff) (newline))

    (define (emit-initializer x port)
      (display "  " port)
      (write (stob-header x) port)
      (write-char #\, port)
      (cond ((d-vector? x)
	     (emit-d-vector-initializer x port))
	    ((vm-string? x)
	     (write-char #\" port)
	     (let ((len (vm-string-length x)))
	       (do ((i 0 (+ i 1)))
		   ((= i len) (write-char #\" port))
		 (let ((c (vm-string-ref x i)))
		   (cond ((or (char=? c #\") (char=? c #\\))
			  (write-char #\\ port))
			 ((char=? c #\newline)
			  (display "\\n\\" port)))
		   (write-char c port)))))
	    (else
	     (write-char #\{ port)
	     (let ((len (b-vector-length x)))
	       (do ((i 0 (+ i 1)))
		   ((= i len) (write-char #\} port))
		 (write (b-vector-ref x i) port)
		 (write-char #\, port)))))
      (write-char #\, port)
      (if *comments?*
	  (begin (display " /* " port)
		 (writex x port)
		 (display " */" port)))
      (newline port))

    (define (emit-d-vector-initializer x port)
      (write-char #\{ port)
      (let ((len (d-vector-length x)))
	(do ((i 0 (+ i 1)))
	    ((= i len) (write-char #\} port))
	  (emit-descriptor (d-vector-ref x i) port)
	  (write-char #\, port))))

    (define (emit-descriptor x port)
      (if (stob? x)
	  (begin (if (immutable? x)
		     (display "D(p" port)
		     (display "D(i" port))
		 (display (chunk-number x) port)
		 (display ".x" port)
		 (writex x port)
		 (write-char #\) port))
	  (write x port)))


					; Foo

    (define (writex x port)
      (write (quotient (- (- x (memory-begin)) 7) 4) port))

    (define (chunk-number x)
      (quotient (- (- x (memory-begin)) 7) *chunk-size*))


					; Image traversal utility

    (define (for-each-stored-object chunk-start proc chunk-end)
      (let ((limit (heap-pointer)))
	(let chunk-loop ((addr (newspace-begin))
			 (i 0)
			 (chunk (+ (newspace-begin) *chunk-size*)))
	  (if (addr< addr limit)
	      (begin (chunk-start i)
		     (let loop ((addr addr))
		       (if (and (addr< addr limit)
				(addr< addr chunk))
			   (let ((d (fetch addr)))
			     (if (not (header? d))
				 (warn "heap is in an inconsistent state" d))
			     (proc (address->stob-descriptor (addr1+ addr)))
			     (loop (addr1+ (addr+ addr (header-a-units d)))))
			   (begin (chunk-end i)
				  (chunk-loop addr
					      (+ i 1)
					      (+ chunk *chunk-size*))))))))))

    (define (mutable? x) (not (immutable? x)))

    ;; End begin
    ))