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-mem-ref-word ez-globalvartab-addr))))
104 (defun ez-set-global-var (gvar val)
105 (ez-mem-set-word (+ (* 2 gvar) (ez-mem-ref-word 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)))))
201 (defvar ez-zstring-alphabets
204 (list " abcdefghijklmnopqrstuvwxyz"
205 " ABCDEFGHIJKLMNOPQRSTUVWXYZ"
206 " \n0123456789.,!?_#'\"/\\-:()")
207 "Alphabets used by V3")
209 (defun ez-parse-zstring-word (word)
211 (logand (lsh word -10) #b11111)
212 (logand (lsh word -5) #b11111)
213 (logand word #b11111)))
215 (defun ez-get-zstring-chars (base-addr)
216 (let ((addr base-addr)
220 (let ((components (ez-parse-zstring-word (ez-mem-ref-word addr))))
221 (setq chars (append chars (cdr components)))
222 (setq addr (+ addr 2))
223 (when (= (car components) 1)
224 (setq not-done nil))))
227 (defun ez-get-zstring (base-addr)
228 (let ((chars (ez-get-zstring-chars base-addr))
237 (* 2 (ez-mem-ref-word (+ ez-abbrevtab-addr
238 (* 2 (+ (* (- abbrev-char 1) 32) char)))))))
239 (setq s (concat s (ez-get-zstring abbrev-addr))))
240 (setq abbrev-char nil))
241 ((memq char '(1 2 3)) ;Abbreviation
242 (setq abbrev-char char))
244 (setq cur (mod (+ cur 1) 3)))
246 (setq cur (mod (+ 3 (- cur 1)) 3)))
248 (setq s (concat s (substring (elt ez-zstring-alphabets cur)
256 (defvar ez-call-stack nil)
258 (defun ez-make-call-stack-frame (pc &optional call-method)
264 (defun ez-add-call-stack-frame (pc &optional call-method)
265 (push (ez-make-call-stack-frame pc call-method) ez-call-stack))
267 (defun ez-pop-call-stack-frame ()
270 (defun ez-routine-stack ()
271 (elt (car ez-call-stack) 1))
273 (defun ez-routine-stack-push (val)
274 (let ((frame (car ez-call-stack)))
275 (setf (elt frame 1) (cons val (elt frame 1)))))
277 (defun ez-routine-stack-pop ()
278 (let* ((frame (car ez-call-stack))
279 (rs-head (car (elt frame 1))))
280 (setf (elt frame 1) (cdr (elt frame 1)))
283 (defun ez-get-local-var (lvar)
284 (let ((frame (car ez-call-stack)))
285 (aref (elt frame 2) (- lvar 1))))
287 (defun ez-set-local-var (lvar val)
288 (let ((frame (car ez-call-stack)))
289 (aset (elt frame 2) (- lvar 1) val)))
292 (caar ez-call-stack))
294 (defun ez-set-pc (new-pc)
295 (setf (car (car ez-call-stack)) new-pc))
297 (defun ez-increment-pc (inc)
298 (ez-set-pc (+ (ez-get-pc) inc)))
300 (defun ez-read-pc-byte-and-inc ()
301 (let ((res (ez-mem-ref-byte (ez-get-pc))))
305 (defun ez-read-pc-word-and-inc ()
306 (let ((res (ez-mem-ref-word (ez-get-pc))))
310 ;; Instruction execution
312 (defun ez-get-var (var)
315 (ez-routine-stack-pop))
317 (ez-get-local-var var))
319 (ez-get-global-var (- var 16)))))
321 (defun ez-set-var (var val)
324 (ez-routine-stack-push val))
326 (ez-set-local-var var val))
328 (ez-set-global-var (- var 16) val))))
330 (defun ez-read-pc-var-and-inc ()
331 (ez-get-var (ez-read-pc-byte-and-inc)))
333 (defun ez-execute-instr ()
334 (let ((instr-pc (ez-get-pc))
335 (opbyte (ez-read-pc-byte-and-inc))
340 ((<= #x0 opbyte #x1f)
343 operands (list (ez-read-pc-byte-and-inc)
344 (ez-read-pc-byte-and-inc))
345 operand-types '(b b)))
346 ((<= #x20 opbyte #x3F)
348 opcode (- opbyte #x20)
349 operands (list (ez-read-pc-byte-and-inc)
350 (ez-read-pc-var-and-inc))
351 operand-types '(b w)))
352 ((<= #x40 opbyte #x5F)
354 opcode (- opbyte #x40)
355 operands (list (ez-read-pc-var-and-inc)
356 (ez-read-pc-byte-and-inc))
357 operand-types '(w b)))
358 ((<= #x60 opbyte #x7F)
360 opcode (- opbyte #x60)
361 operands (list (ez-read-pc-var-and-inc)
362 (ez-read-pc-var-and-inc))
363 operand-types '(w w)))
364 ((<= #x80 opbyte #x8F)
366 opcode (- opbyte #x80)
367 operands (list (ez-read-pc-word-and-inc))
369 ((<= #x90 opbyte #x9F)
371 opcode (- opbyte #x90)
372 operands (list (ez-read-pc-byte-and-inc))
374 ((<= #xA0 opbyte #xAF)
376 opcode (- opbyte #xa0)
377 operands (list (ez-read-pc-var-and-inc))
379 ((<= #xB0 opbyte #xBF)
381 opcode (- opbyte #xb0)))
382 ((<= #xC0 opbyte #xDF)
383 (error "Unsupported op" opbyte))
384 ((<= #xE0 opbyte #xFF)
386 opcode (- opbyte #xe0))
387 (let ((operands-and-types (ez-read-var-operands-and-inc)))
388 (setq operands (car operands-and-types)
389 operand-types (cdr operands-and-types)))))
390 (let ((table-row (assoc (list optype opcode) ez-op-table)))
392 (error "Unsupported op" instr-pc optype opcode operands operand-types))
393 (let ((mnemonic (elt table-row 1)))
394 (message "PC:%x Optype:%s Opcode:%x Mnemonic:%s Operands:%s"
395 instr-pc optype opcode mnemonic operands))
396 (funcall (elt table-row 2) operands operand-types))))
398 (defun ez-read-var-operands-and-inc ()
399 (let* ((type-byte (ez-read-pc-byte-and-inc))
400 (types (let ((type1 (lsh type-byte -6)))
404 (let ((type2 (lsh (logand #b110000 type-byte) -4)))
408 (let ((type3 (lsh (logand #b1100 type-byte) -2)))
412 (let ((type4 (logand #b11)))
415 (list type4)))))))))))))
421 ((= type 0) (ez-read-pc-word-and-inc))
422 ((= type 1) (ez-read-pc-byte-and-inc))
423 ((= type 2) (ez-read-pc-var-and-inc))))
434 (defun ez-do-branch (branch)
435 (let* ((branch-byte (ez-read-pc-byte-and-inc))
436 (invert (= 0 (logand branch-byte #b10000000)))
437 (single-byte (= 1 (logand branch-byte #b01000000)))
440 (logand branch-byte #b00111111)
441 (let ((pos (= (logand branch-byte #b00100000) 0))
442 (val (+ (* 256 (logand branch-byte #b00011111))
443 (ez-read-pc-byte-and-inc))))
453 (ez-set-pc (+ (ez-get-pc) offset -2))))))
458 '(((0op #x00) rtrue ez-op-rtrue)
459 ((0op #x01) rfalse ez-op-rfalse)
460 ((1op #x00) jz ez-op-jz)
461 ((1op #x0B) ret ez-op-ret)
462 ((1op #x0C) jump ez-op-jump)
463 ((2op #x0D) store ez-op-store)
464 ((1op #x0E) load ez-op-load)
465 ((var #x01) storew ez-op-storew)
466 ((2op #x01) je ez-op-je)
467 ((2op #x08) or ez-op-or)
468 ((2op #x09) and ez-op-and)
469 ((2op #x14) add ez-op-add)
470 ((2op #x15) sub ez-op-sub)
471 ((2op #x16) mul ez-op-mul)
472 ((2op #x17) div ez-op-div)
473 ((2op #x18) mod ez-op-mod)
474 ((var #x00) call_fv ez-op-callf)
475 ((1op #x01) get_sibling ez-op-get-sibling)
476 ((1op #x02) get_child ez-op-get-child)
477 ((1op #x03) get_parent ez-op-get-parent)
478 ((var #x03) put_prop ez-op-put-prop)))
480 (defun ez-op-ret (operands &optional operand-types)
481 (let ((retval (car operands)))
482 (ez-pop-call-stack-frame)
483 (ez-set-var (ez-read-pc-byte-and-inc) retval))
486 (defun ez-op-rtrue (&optional operands operand-types)
487 (ez-op-ret (list 1)))
489 (defun ez-op-rfalse (&optional operands operand-types)
490 (ez-op-ret (list 0)))
492 (defun ez-op-jz (operands operand-types)
493 (ez-do-branch (= (car operands) 0))
496 (defun ez-op-je (operands operand-types)
497 (ez-do-branch (memq (car operands) (cdr operands)))
500 (defun ez-op-jump (operands operand-types)
501 (let ((offset (if (eq (car operand-types) 'b)
502 (ez-decode-signed-byte (car operands))
503 (ez-decode-signed-word (car operands)))))
504 (ez-set-pc (+ (ez-get-pc) offset -2)))
507 (defun ez-op-store (operands operand-types)
508 (let ((var (car operands))
513 (defun ez-op-load (operands operand-types)
514 (let ((var (car operands)))
515 (ez-set-var (ez-read-pc-byte-and-inc) (ez-get-var var)))
518 (defun ez-op-storew (operands operand-types)
519 (let ((baddr (car operands))
521 (a (caddr operands)))
522 (ez-mem-set-word (+ baddr (* 2 n)) a))
525 (defun ez-op-and (operands operand-types)
526 (let ((a (car operands))
528 (ez-set-var (ez-read-pc-byte-and-inc) (logand a b)))
531 (defun ez-op-or (operands operand-types)
532 (let ((a (car operands))
534 (ez-set-var (ez-read-pc-byte-and-inc) (logior a b)))
537 (defun ez-op-add (operands operand-types)
538 (let ((a (car operands))
540 (ez-set-var (ez-read-pc-byte-and-inc) (mod (+ a b) #x10000)))
543 (defun ez-op-sub (operands operand-types)
544 (let ((a (car operands))
546 (ez-set-var (ez-read-pc-byte-and-inc) (mod (+ (- a b) #x10000) #x10000)))
549 (defun ez-op-mul (a b)
550 (let ((a (car operands))
552 (ez-set-var (ez-read-pc-byte-and-inc) (mod (* a b) #x10000)))
555 (defun ez-op-div (a b)
556 (error "Not implemented"))
558 (defun ez-op-mod (a b)
559 (error "Not implemented"))
561 (defun ez-op-callf (operands operand-types)
562 (let* ((raddr (car operands))
563 (call-operands (cdr operands))
565 (L (ez-mem-ref-byte r))
566 (n (length call-operands))
567 (new-pc (+ r 1 (* L 2))))
568 (ez-add-call-stack-frame new-pc)
571 (ez-set-local-var (+ i 1) (elt call-operands i))
572 (ez-set-local-var (+ i 1) (ez-mem-ref-word (+ r 1 (* 2 i)))))))
575 (defun ez-op-get-sibling (operands operand-types)
576 (let ((sib (ez-get-obj-sibling (car operands))))
577 (ez-set-var (ez-read-pc-byte-and-inc) sib)
578 (ez-do-branch (> sib 0))))
580 (defun ez-op-get-child (operands operand-types)
581 (let ((child (ez-get-obj-child (car operands))))
582 (ez-set-var (ez-read-pc-byte-and-inc) child)
583 (ez-do-branch (> child 0))))
585 (defun ez-op-get-parent (operands operand-types)
586 (let ((parent (ez-get-obj-parent (car operands))))
587 (ez-set-var (ez-read-pc-byte-and-inc) parent)
588 (ez-do-branch (> parent 0))))
590 (defun ez-op-put-prop (operands operand-types)
591 (let* ((obj (car operands))
592 (prop (cadr operands))
593 (a (caddr operands)))
594 (ez-set-obj-prop obj prop a)))
598 (defun ez-run (filename)
599 (ez-load-file filename)
601 (setq ez-call-stack (list (ez-make-call-stack-frame ez-start-pc)))
603 (while (ez-execute-instr)))
607 ;; (ez-load-file "zork1.z3")
609 ;; (setq ez-call-stack (list (ez-make-call-stack-frame ez-start-pc)))
610 ;; (while (ez-execute-instr))