1 ;;; ez.el --- Emacs Z-machine
3 ;; Copyright (C) 2021 Tim Vaughan
5 ;; Author: Tim Vaughan <timv@ughan.xyz>
6 ;; Created: 13 Oct 2021
9 ;; Homepage: http://thelambdalab.xyz/ez
10 ;; Package-Requires: ((emacs "26"))
12 ;; This file is not part of GNU Emacs.
14 ;; This program is free software: you can redistribute it and/or modify
15 ;; it under the terms of the GNU General Public License as published by
16 ;; the Free Software Foundation, either version 3 of the License, or
17 ;; (at your option) any later version.
19 ;; This program is distributed in the hope that it will be useful,
20 ;; but WITHOUT ANY WARRANTY; without even the implied warranty of
21 ;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
22 ;; GNU General Public License for more details.
24 ;; You should have received a copy of the GNU General Public License
25 ;; along with this file. If not, see <http://www.gnu.org/licenses/>.
33 (defun ez-decode-signed-bits (n nbits)
34 (if (= 0 (lsh n (- 1 nbits)))
38 (defun ez-decode-signed-byte (b)
39 (ez-decode-signed-bits b 8))
41 (defun ez-decode-signed-word (w)
42 (ez-decode-signed-bits w 16))
44 (defun binformat (n &optional s)
48 (new-s (concat (number-to-string (mod n 2)) s)))
51 (binformat d new-s))))
56 "Memory of z-machine.")
58 (defvar ez-version nil)
60 (defvar ez-start-pc nil)
61 (defvar ez-himem-base nil)
62 (defvar ez-dict-addr nil)
63 (defvar ez-objtab-addr nil)
64 (defvar ez-abbrevtab-addr nil)
65 (defvar ez-globalvartab-addr nil)
67 (defun ez-mem-ref-byte (addr)
68 (aref ez-memory addr))
70 (defun ez-mem-set-byte (addr val)
71 (aset ez-memory addr val))
73 (defun ez-mem-ref-word (addr)
74 (+ (* 256 (aref ez-memory addr))
75 (aref ez-memory (+ addr 1))))
77 (defun ez-mem-set-word (addr val)
78 (let ((byte-high (/ val 256))
79 (byte-low (mod val 256)))
80 (aset ez-memory addr byte-high)
81 (aset ez-memory (+ addr 1) byte-low)))
83 (defun ez-parse-header ()
84 (setq ez-version (ez-mem-ref-byte #x0))
85 (setq ez-himem-addr (ez-mem-ref-word #x4))
86 (setq ez-start-pc (ez-mem-ref-word #x6))
87 (setq ez-dict-base (ez-mem-ref-word #x8))
88 (setq ez-objtab-addr (ez-mem-ref-word #xA))
89 (setq ez-globalvartab-addr (ez-mem-ref-word #xC))
90 (setq ez-abbrevtab-addr (ez-mem-ref-word #x18)))
92 (defun ez-load-file (filename)
93 "Load story file into memory."
95 (insert-file-contents-literally filename)
96 (setq ez-memory (encode-coding-string (buffer-string) 'raw-text)))
101 (defun ez-get-global-var (gvar)
102 (ez-mem-ref-word (+ (* 2 gvar) ez-globalvartab-addr)))
104 (defun ez-set-global-var (gvar val)
105 (ez-mem-set-word (+ (* 2 gvar) ez-globalvartab-addr) val))
109 (defvar ez-property-defaults nil)
111 (defun ez-load-property-defaults ()
112 (setq ez-property-defaults (make-vector 31 0))
114 (aset ez-property-defaults i (aref ez-memory (+ ez-objtab-addr (* 2 i))))))
116 (defun ez-get-obj-addr (obj-id)
117 (+ ez-objtab-addr (* 2 31) (* 9 (- obj-id 1))))
119 (defun ez-get-obj-parent (obj-id)
120 (let ((addr (ez-get-obj-addr obj-id)))
121 (ez-mem-ref-byte (+ addr 4))))
123 (defun ez-get-obj-sibling (obj-id)
124 (let ((addr (ez-get-obj-addr obj-id)))
125 (ez-mem-ref-byte (+ addr 5))))
127 (defun ez-get-obj-child (obj-id)
128 (let ((addr (ez-get-obj-addr obj-id)))
129 (ez-mem-ref-byte (+ addr 6))))
131 (defun ez-get-obj-plist-addr (obj-id)
132 (let ((addr (ez-get-obj-addr obj-id)))
133 (ez-mem-ref-word (+ addr 7))))
135 (defun ez-get-obj-name (obj-id)
136 (let ((plist-addr (ez-get-obj-plist-addr obj-id)))
137 (if (> (ez-mem-ref-byte plist-addr) 0)
138 (ez-get-zstring (+ 1 (ez-get-obj-plist-addr obj-id)))
141 (defun ez-get-obj (obj-id)
142 (let ((addr (+ ez-objtab-addr
144 (* 9 (- obj-id 1)))))
147 (ez-mem-ref-byte (+ addr 4))
148 (ez-mem-ref-byte (+ addr 5))
149 (ez-mem-ref-byte (+ addr 6))
150 (ez-mem-ref-word (+ addr 7))
151 (let ((plist-addr (ez-mem-ref-word (+ addr 7))))
152 (if (> (ez-mem-ref-byte plist-addr) 0)
153 (ez-get-zstring (+ 1 plist-addr))
156 (defun ez-get-prop-default (prop)
157 (ez-mem-ref-word (+ ez-objtab-addr (* 2 (+ 1 prop)))))
159 (defun ez-get-prop-len (prop-size-byte)
160 (lsh prop-size-byte -5))
162 (defun ez-get-prop-num (prop-size-byte)
163 (logand #b00011111 prop-size-byte))
165 (defun ez-get-obj-prop-addr (obj prop)
166 (let* ((plist-addr (ez-get-obj-plist-addr obj))
167 (prop-addr (+ plist-addr 1 (* 2 (ez-mem-ref-byte plist-addr))))
168 (size-byte (ez-mem-ref-byte prop-addr)))
169 (while (not (or (= size-byte 0)
170 (= prop (ez-get-prop-num size-byte))))
171 (setq prop-addr (+ prop-addr (ez-get-prop-len size-byte) 2)
172 size-byte (ez-mem-ref-byte prop-addr)))
175 (defun ez-get-obj-prop (obj prop)
176 (let* ((prop-addr (ez-get-obj-prop-addr obj prop))
177 (size-byte (ez-mem-ref-byte prop-addr)))
179 (ez-get-prop-default prop)
180 (let ((prop-len (ez-get-prop-len size-byte))
181 (data-addr (+ prop-addr 1)))
184 (ez-mem-ref-byte data-addr))
186 (ez-mem-ref-word data-addr)))))))
188 (defun ez-set-obj-prop (obj prop value)
189 (let* ((prop-addr (ez-get-obj-prop-addr obj prop))
190 (size-byte (ez-mem-ref-byte prop-addr)))
193 (error "Tried to set non-existant property"))
194 ((= (ez-get-prop-len size-byte) 1)
195 (ez-mem-set-byte (+ prop-addr 1) value))
197 (ez-mem-set-word (+ prop-addr 1) value)))))
199 (defun ez-get-obj-attr (obj attr)
200 (let* ((byte-num (/ attr 8))
201 (bit-num (mod attr 8))
202 (bit-mask (lsh 1 (- 7 bit-num))))
203 (if (> (logand bit-mask (ez-mem-ref-byte (+ (ez-get-obj-addr obj) byte-num))) 0)
207 (defun ez-set-obj-attr (obj attr val)
208 (let* ((byte-num (/ attr 8))
209 (bit-num (mod attr 8))
210 (bit-mask (lsh 1 (- 7 bit-num)))
211 (byte-addr (+ (ez-get-obj-addr obj) byte-num))
212 (byte (ez-mem-ref-byte byte-addr))
213 (current-set (> (logand bit-mask byte) 0)))
214 (if (or (and current-set (= val 0))
215 (and (not current-set) (> val 0)))
216 (ez-mem-set-byte byte-addr (logxor byte bit-mask)))))
220 (defvar ez-zstring-alphabets
223 (list " abcdefghijklmnopqrstuvwxyz"
224 " ABCDEFGHIJKLMNOPQRSTUVWXYZ"
225 " \n0123456789.,!?_#'\"/\\-:()")
226 "Alphabets used by V3")
228 (defun ez-parse-zstring-word (word)
230 (logand (lsh word -10) #b11111)
231 (logand (lsh word -5) #b11111)
232 (logand word #b11111)))
234 (defun ez-get-zstring-chars (base-addr)
235 (let ((addr base-addr)
239 (let ((components (ez-parse-zstring-word (ez-mem-ref-word addr))))
240 (setq chars (append chars (cdr components)))
241 (setq addr (+ addr 2))
242 (when (= (car components) 1)
243 (setq not-done nil))))
246 (defun ez-get-zstring (base-addr)
247 (let ((chars (ez-get-zstring-chars base-addr))
256 (* 2 (ez-mem-ref-word (+ ez-abbrevtab-addr
257 (* 2 (+ (* (- abbrev-char 1) 32) char)))))))
258 (setq s (concat s (ez-get-zstring abbrev-addr))))
259 (setq abbrev-char nil))
260 ((memq char '(1 2 3)) ;Abbreviation
261 (setq abbrev-char char))
263 (setq cur (mod (+ cur 1) 3)))
265 (setq cur (mod (+ 3 (- cur 1)) 3)))
267 (setq s (concat s (substring (elt ez-zstring-alphabets cur)
275 (defvar ez-call-stack nil)
277 (defun ez-make-call-stack-frame (pc &optional call-method)
283 (defun ez-add-call-stack-frame (pc &optional call-method)
284 (push (ez-make-call-stack-frame pc call-method) ez-call-stack))
286 (defun ez-pop-call-stack-frame ()
289 (defun ez-routine-stack ()
290 (elt (car ez-call-stack) 1))
292 (defun ez-routine-stack-push (val)
293 (let ((frame (car ez-call-stack)))
294 (setf (elt frame 1) (cons val (elt frame 1)))))
296 (defun ez-routine-stack-pop ()
297 (let* ((frame (car ez-call-stack))
298 (rs-head (car (elt frame 1))))
299 (setf (elt frame 1) (cdr (elt frame 1)))
302 (defun ez-get-local-var (lvar)
303 (let ((frame (car ez-call-stack)))
304 (aref (elt frame 2) (- lvar 1))))
306 (defun ez-set-local-var (lvar val)
307 (let ((frame (car ez-call-stack)))
308 (aset (elt frame 2) (- lvar 1) val)))
311 (caar ez-call-stack))
313 (defun ez-set-pc (new-pc)
314 (setf (car (car ez-call-stack)) new-pc))
316 (defun ez-increment-pc (inc)
317 (ez-set-pc (+ (ez-get-pc) inc)))
319 (defun ez-read-pc-byte-and-inc ()
320 (let ((res (ez-mem-ref-byte (ez-get-pc))))
324 (defun ez-read-pc-word-and-inc ()
325 (let ((res (ez-mem-ref-word (ez-get-pc))))
329 ;; Instruction execution
331 (defun ez-get-var (var)
334 (ez-routine-stack-pop))
336 (ez-get-local-var var))
338 (ez-get-global-var (- var 16)))))
340 (defun ez-set-var (var val)
343 (ez-routine-stack-push val))
345 (ez-set-local-var var val))
347 (ez-set-global-var (- var 16) val))))
349 (defun ez-read-pc-var-and-inc ()
350 (ez-get-var (ez-read-pc-byte-and-inc)))
352 (defun ez-execute-instr ()
353 (let ((instr-pc (ez-get-pc))
354 (opbyte (ez-read-pc-byte-and-inc))
359 ((<= #x0 opbyte #x1f)
362 operands (list (ez-read-pc-byte-and-inc)
363 (ez-read-pc-byte-and-inc))
364 operand-types '(b b)))
365 ((<= #x20 opbyte #x3F)
367 opcode (- opbyte #x20)
368 operands (list (ez-read-pc-byte-and-inc)
369 (ez-read-pc-var-and-inc))
370 operand-types '(b w)))
371 ((<= #x40 opbyte #x5F)
373 opcode (- opbyte #x40)
374 operands (list (ez-read-pc-var-and-inc)
375 (ez-read-pc-byte-and-inc))
376 operand-types '(w b)))
377 ((<= #x60 opbyte #x7F)
379 opcode (- opbyte #x60)
380 operands (list (ez-read-pc-var-and-inc)
381 (ez-read-pc-var-and-inc))
382 operand-types '(w w)))
383 ((<= #x80 opbyte #x8F)
385 opcode (- opbyte #x80)
386 operands (list (ez-read-pc-word-and-inc))
388 ((<= #x90 opbyte #x9F)
390 opcode (- opbyte #x90)
391 operands (list (ez-read-pc-byte-and-inc))
393 ((<= #xA0 opbyte #xAF)
395 opcode (- opbyte #xa0)
396 operands (list (ez-read-pc-var-and-inc))
398 ((<= #xB0 opbyte #xBF)
400 opcode (- opbyte #xb0)
403 ((<= #xC0 opbyte #xDF)
404 (error "Unsupported op %x" opbyte))
405 ((<= #xE0 opbyte #xFF)
407 opcode (- opbyte #xe0))
408 (let ((operands-and-types (ez-read-var-operands-and-inc)))
409 (setq operands (car operands-and-types)
410 operand-types (cdr operands-and-types)))))
411 (let ((table-row (assoc (list optype opcode) ez-op-table)))
413 (error "Unsupported op PC:%x Optype:%s Opcode:%x Operands:%s Operand-types:%s"
414 instr-pc optype opcode operands operand-types))
415 (let ((mnemonic (elt table-row 1)))
416 (message "PC:%x Optype:%s Opcode:%x Mnemonic:%s Operands:%s Operand-types:%s"
417 instr-pc optype opcode mnemonic operands operand-types))
418 (funcall (elt table-row 2) operands operand-types))))
420 (defun ez-read-var-operands-and-inc ()
421 (let* ((type-byte (ez-read-pc-byte-and-inc))
422 (types (let ((type1 (lsh type-byte -6)))
426 (let ((type2 (lsh (logand #b110000 type-byte) -4)))
430 (let ((type3 (lsh (logand #b1100 type-byte) -2)))
434 (let ((type4 (logand #b11)))
437 (list type4))))))))))))))
442 ((= type 0) (ez-read-pc-word-and-inc))
443 ((= type 1) (ez-read-pc-byte-and-inc))
444 ((= type 2) (ez-read-pc-var-and-inc))))
455 (defun ez-do-branch (branch)
456 (let* ((branch-byte (ez-read-pc-byte-and-inc))
457 (invert (= 0 (logand branch-byte #b10000000)))
458 (single-byte (> (logand branch-byte #b01000000) 0))
461 (logand branch-byte #b00111111)
462 (let ((pos (= (logand branch-byte #b00100000) 0))
463 (val (+ (* 256 (logand branch-byte #b00011111))
464 (ez-read-pc-byte-and-inc))))
468 (if (or (and branch (not invert))
469 (and (not branch) invert))
476 (ez-set-pc (+ (ez-get-pc) offset -2)))))))
481 '(((0op #x00) rtrue ez-op-rtrue)
482 ((0op #x01) rfalse ez-op-rfalse)
483 ((1op #x00) jz ez-op-jz)
484 ((1op #x0B) ret ez-op-ret)
485 ((1op #x0C) jump ez-op-jump)
486 ((2op #x0D) store ez-op-store)
487 ((1op #x0E) load ez-op-load)
488 ((var #x01) storew ez-op-storew)
489 ((2op #x0F) loadw ez-op-loadw)
490 ((2op #x01) je ez-op-je)
491 ((2op #x08) or ez-op-or)
492 ((2op #x09) and ez-op-and)
493 ((2op #x14) add ez-op-add)
494 ((2op #x15) sub ez-op-sub)
495 ((2op #x16) mul ez-op-mul)
496 ((2op #x17) div ez-op-div)
497 ((2op #x18) mod ez-op-mod)
498 ((var #x00) call_fv ez-op-callf)
499 ((1op #x01) get_sibling ez-op-get-sibling)
500 ((1op #x02) get_child ez-op-get-child)
501 ((1op #x03) get_parent ez-op-get-parent)
502 ((2op #x0A) test_attr ez-op-test-attr)
503 ((var #x03) put_prop ez-op-put-prop)
504 ((0op #x02) print ez-op-print)))
506 (defun ez-op-ret (operands &optional operand-types)
507 (let ((retval (car operands)))
508 (ez-pop-call-stack-frame)
509 (ez-set-var (ez-read-pc-byte-and-inc) retval))
512 (defun ez-op-rtrue (&optional operands operand-types)
516 (defun ez-op-rfalse (&optional operands operand-types)
520 (defun ez-op-jz (operands operand-types)
521 (ez-do-branch (= (car operands) 0))
524 (defun ez-op-je (operands operand-types)
525 (ez-do-branch (memq (car operands) (cdr operands)))
528 (defun ez-op-jump (operands operand-types)
529 (let ((offset (if (eq (car operand-types) 'b)
530 (ez-decode-signed-byte (car operands))
531 (ez-decode-signed-word (car operands)))))
532 (ez-set-pc (+ (ez-get-pc) offset -2)))
535 (defun ez-op-store (operands operand-types)
536 (let ((var (car operands))
541 (defun ez-op-load (operands operand-types)
542 (let ((var (car operands)))
543 (ez-set-var (ez-read-pc-byte-and-inc) (ez-get-var var)))
546 (defun ez-op-storew (operands operand-types)
547 (let ((baddr (car operands))
549 (a (caddr operands)))
550 (ez-mem-set-word (+ baddr (* 2 n)) a))
553 (defun ez-op-loadw (operands operand-types)
554 (let ((baddr (car operands))
556 (ez-set-var (ez-read-pc-byte-and-inc) (ez-mem-ref-word (+ baddr (* 2 n)))))
559 (defun ez-op-and (operands operand-types)
560 (let ((a (car operands))
562 (ez-set-var (ez-read-pc-byte-and-inc) (logand a b)))
565 (defun ez-op-or (operands operand-types)
566 (let ((a (car operands))
568 (ez-set-var (ez-read-pc-byte-and-inc) (logior a b)))
571 (defun ez-op-add (operands operand-types)
572 (let ((a (car operands))
574 (ez-set-var (ez-read-pc-byte-and-inc) (mod (+ a b) #x10000)))
577 (defun ez-op-sub (operands operand-types)
578 (let ((a (car operands))
580 (ez-set-var (ez-read-pc-byte-and-inc) (mod (+ (- a b) #x10000) #x10000)))
583 (defun ez-op-mul (a b)
584 (let ((a (car operands))
586 (ez-set-var (ez-read-pc-byte-and-inc) (mod (* a b) #x10000)))
589 (defun ez-op-div (a b)
590 (error "Not implemented"))
592 (defun ez-op-mod (a b)
593 (error "Not implemented"))
595 (defun ez-op-callf (operands operand-types)
596 (let* ((raddr (car operands))
597 (call-operands (cdr operands))
599 (L (ez-mem-ref-byte r))
600 (n (length call-operands))
601 (new-pc (+ r 1 (* L 2))))
602 (ez-add-call-stack-frame new-pc)
605 (ez-set-local-var (+ i 1) (elt call-operands i))
606 (ez-set-local-var (+ i 1) (ez-mem-ref-word (+ r 1 (* 2 i)))))))
609 (defun ez-op-test-attr (operands operand-types)
610 (let ((obj (car operands))
611 (attr (cadr operands)))
612 (ez-do-branch (= 1 (ez-get-obj-attr obj attr)))
615 (defun ez-op-get-sibling (operands operand-types)
616 (let ((sib (ez-get-obj-sibling (car operands))))
617 (ez-set-var (ez-read-pc-byte-and-inc) sib)
618 (ez-do-branch (> sib 0))
621 (defun ez-op-get-child (operands operand-types)
622 (let ((child (ez-get-obj-child (car operands))))
623 (ez-set-var (ez-read-pc-byte-and-inc) child)
624 (ez-do-branch (> child 0))
627 (defun ez-op-get-parent (operands operand-types)
628 (let ((parent (ez-get-obj-parent (car operands))))
629 (ez-set-var (ez-read-pc-byte-and-inc) parent)
630 (ez-do-branch (> parent 0))
633 (defun ez-op-put-prop (operands operand-types)
634 (let* ((obj (car operands))
635 (prop (cadr operands))
636 (a (caddr operands)))
637 (ez-set-obj-prop obj prop a)
640 (defun ez-op-print (operands operand-types)
641 (ez-print (ez-get-zstring (ez-get-pc)))
647 (defun ez-run (filename)
648 (ez-load-file filename)
650 (setq ez-call-stack (list (ez-make-call-stack-frame ez-start-pc)))
652 (while (ez-execute-instr)))
658 (defun ez-render-prompt ()
659 (with-current-buffer "*ez*"
660 (let ((update-point (= ez-input-marker (point)))
661 (update-window-points (mapcar (lambda (w)
662 (list (= (window-point w) ez-input-marker)
664 (get-buffer-window-list nil nil t))))
666 (set-marker-insertion-type ez-prompt-marker nil)
667 (set-marker-insertion-type ez-input-marker t)
668 (let ((inhibit-read-only t))
669 (delete-region ez-prompt-marker ez-input-marker)
670 (goto-char ez-prompt-marker)
673 (propertize " " ; Need this to be separate to mark it as rear-nonsticky
676 (set-marker-insertion-type ez-input-marker nil))
677 (goto-char ez-input-marker))))
679 (defvar ez-prompt-marker nil
680 "Marker for prompt position in buffer.")
682 (defvar ez-input-marker nil
683 "Marker for prompt position in buffer.")
685 (defun ez-setup-buffer ()
686 (with-current-buffer (get-buffer-create "*ez*")
687 (let ((inhibit-read-only t))
688 (delete-region (point-min) (point-max)))
689 (setq-local scroll-conservatively 1)
690 (if (markerp ez-prompt-marker)
691 (set-marker ez-prompt-marker (point-max))
692 (setq ez-prompt-marker (point-max-marker)))
693 (if (markerp ez-input-marker)
694 (set-marker ez-input-marker (point-max))
695 (setq ez-input-marker (point-max-marker)))
696 (goto-char (point-max))
700 (defun ez-print (string)
701 (with-current-buffer "*ez*"
703 (goto-char ez-prompt-marker)
704 (insert-before-markers string))))
709 (let ((map (make-sparse-keymap)))
710 (define-key map (kbd "RET") 'ez-enter)
713 (define-derived-mode ez-mode text-mode "ez"
714 "Major mode for EZ.")
716 (when (fboundp 'evil-set-initial-state)
717 (evil-set-initial-state 'ez-mode 'insert))
720 (interactive "fEnter name of z3 story file: ")
721 (if (get-buffer "*ez*")
722 (switch-to-buffer "*ez*")
723 (switch-to-buffer "*ez*")
731 (switch-to-buffer "*ez*")