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/>.
29 ;; There are many Z-machine interpreters, but this one is mine.
30 ;; It only capable of interpreting the subset of Z-code necessary
31 ;; to run the first Zork game in z3 format.
33 ;; It is based entirely on the description of the Z-machine contained
34 ;; Marnix Klooster's wonderful document, "The Z-machine And How to Emulate It."
40 (defun ez-decode-signed-bits (n nbits)
41 (if (= 0 (lsh n (- 1 nbits)))
45 (defun ez-decode-signed-byte (b)
46 (ez-decode-signed-bits b 8))
48 (defun ez-decode-signed-word (w)
49 (ez-decode-signed-bits w 16))
51 (defun ez-decode-signed-operand (operand operand-type)
52 (if (eq operand-type 'b)
53 (ez-decode-signed-byte operand)
54 (ez-decode-signed-word operand)))
56 (defun binformat (n &optional s)
60 (new-s (concat (number-to-string (mod n 2)) s)))
63 (binformat d new-s))))
65 (defun ez-list-to-string-hex (l)
70 (apply 'concat (mapcar (lambda (n) (format " %x" n)) (cdr l)))))
76 "Memory of z-machine.")
78 (defvar ez-version nil)
80 (defvar ez-start-pc nil)
81 (defvar ez-himem-base nil)
82 (defvar ez-dict-base nil)
83 (defvar ez-objtab-addr nil)
84 (defvar ez-abbrevtab-addr nil)
85 (defvar ez-globalvartab-addr nil)
87 (defun ez-mem-ref-byte (addr)
88 (aref ez-memory addr))
90 (defun ez-mem-set-byte (addr val)
91 (aset ez-memory addr val))
93 (defun ez-mem-ref-word (addr)
94 (+ (* 256 (aref ez-memory addr))
95 (aref ez-memory (+ addr 1))))
97 (defun ez-mem-set-word (addr val)
98 (let ((byte-high (/ val 256))
99 (byte-low (mod val 256)))
100 (aset ez-memory addr byte-high)
101 (aset ez-memory (+ addr 1) byte-low)))
103 (defun ez-parse-header ()
104 (setq ez-version (ez-mem-ref-byte #x0))
105 (setq ez-himem-addr (ez-mem-ref-word #x4))
106 (setq ez-start-pc (ez-mem-ref-word #x6))
107 (setq ez-dict-base (ez-mem-ref-word #x8))
108 (setq ez-objtab-addr (ez-mem-ref-word #xA))
109 (setq ez-globalvartab-addr (ez-mem-ref-word #xC))
110 (setq ez-abbrevtab-addr (ez-mem-ref-word #x18)))
112 (defun ez-load-file (filename)
113 "Load story file into memory."
115 (insert-file-contents-literally filename)
116 (setq ez-memory (encode-coding-string (buffer-string) 'raw-text)))
121 (defun ez-get-global-var (gvar)
123 (error "Invalid global variable %d" gvar))
125 (ez-mem-ref-word (+ (* 2 gvar) ez-globalvartab-addr))))
126 (ez-debug-message "\tRetrieved %x from global variable %x" val gvar)
129 (defun ez-set-global-var (gvar val)
130 (ez-mem-set-word (+ (* 2 gvar) ez-globalvartab-addr) val)
131 (ez-debug-message "\tSet global variabl %x to %x" gvar val))
135 (defvar ez-property-defaults nil)
137 (defun ez-load-property-defaults ()
138 (setq ez-property-defaults (make-vector 31 0))
140 (aset ez-property-defaults i (aref ez-memory (+ ez-objtab-addr (* 2 i))))))
142 (defun ez-get-obj-addr (obj)
143 (+ ez-objtab-addr (* 2 31) (* 9 (- obj 1))))
145 (defun ez-get-obj-parent (obj)
146 (let ((addr (ez-get-obj-addr obj)))
147 (ez-mem-ref-byte (+ addr 4))))
149 (defun ez-set-obj-parent (obj new-parent)
150 (let ((addr (ez-get-obj-addr obj)))
151 (ez-mem-set-byte (+ addr 4) new-parent)))
153 (defun ez-get-obj-sibling (obj)
154 (let ((addr (ez-get-obj-addr obj)))
155 (ez-mem-ref-byte (+ addr 5))))
157 (defun ez-set-obj-sibling (obj new-sibling)
158 (let ((addr (ez-get-obj-addr obj)))
159 (ez-mem-set-byte (+ addr 5) new-sibling)))
161 (defun ez-get-obj-child (obj)
162 (let ((addr (ez-get-obj-addr obj)))
163 (ez-mem-ref-byte (+ addr 6))))
165 (defun ez-set-obj-child (obj new-child)
166 (let ((addr (ez-get-obj-addr obj)))
167 (ez-mem-set-byte (+ addr 6) new-child)))
169 (defun ez-get-obj-plist-addr (obj)
170 (let ((addr (ez-get-obj-addr obj)))
171 (ez-mem-ref-word (+ addr 7))))
173 (defun ez-get-obj-name (obj)
174 (let ((plist-addr (ez-get-obj-plist-addr obj)))
175 (if (> (ez-mem-ref-byte plist-addr) 0)
176 (ez-get-zstring (+ 1 (ez-get-obj-plist-addr obj)))
179 (defun ez-get-prop-default (prop)
180 (ez-mem-ref-word (+ ez-objtab-addr (* 2 (+ 1 prop)))))
182 (defun ez-get-prop-len (prop-size-byte)
183 (lsh prop-size-byte -5))
185 (defun ez-get-prop-num (prop-size-byte)
186 (logand #b00011111 prop-size-byte))
188 (defun ez-get-obj-prop-addr (obj prop)
189 (let* ((plist-addr (ez-get-obj-plist-addr obj))
190 (prop-addr (+ plist-addr 1 (* 2 (ez-mem-ref-byte plist-addr))))
191 (size-byte (ez-mem-ref-byte prop-addr)))
192 (while (not (or (= size-byte 0)
193 (= prop (ez-get-prop-num size-byte))))
194 (setq prop-addr (+ prop-addr (ez-get-prop-len size-byte) 2)
195 size-byte (ez-mem-ref-byte prop-addr)))
198 (defun ez-get-obj-prop (obj prop)
199 (let* ((prop-addr (ez-get-obj-prop-addr obj prop))
200 (size-byte (ez-mem-ref-byte prop-addr)))
202 (ez-get-prop-default prop)
203 (let ((prop-len (ez-get-prop-len size-byte))
204 (data-addr (+ prop-addr 1)))
207 (ez-mem-ref-byte data-addr))
209 (ez-mem-ref-word data-addr)))))))
211 (defun ez-set-obj-prop (obj prop value)
212 (let* ((prop-addr (ez-get-obj-prop-addr obj prop))
213 (size-byte (ez-mem-ref-byte prop-addr)))
216 (error "Tried to set non-existant property"))
217 ((= (ez-get-prop-len size-byte) 1)
218 (ez-mem-set-byte (+ prop-addr 1) value))
220 (ez-mem-set-word (+ prop-addr 1) value)))))
222 (defun ez-get-obj-attr (obj attr)
223 (let* ((byte-num (/ attr 8))
224 (bit-num (mod attr 8))
225 (bit-mask (lsh 1 (- 7 bit-num))))
226 (if (> (logand bit-mask (ez-mem-ref-byte (+ (ez-get-obj-addr obj) byte-num))) 0)
230 (defun ez-set-obj-attr (obj attr val)
231 (let* ((byte-num (/ attr 8))
232 (bit-num (mod attr 8))
233 (bit-mask (lsh 1 (- 7 bit-num)))
234 (byte-addr (+ (ez-get-obj-addr obj) byte-num))
235 (byte (ez-mem-ref-byte byte-addr))
236 (current-set (> (logand bit-mask byte) 0)))
237 (if (or (and current-set (= val 0))
238 (and (not current-set) (> val 0)))
239 (ez-mem-set-byte byte-addr (logxor byte bit-mask)))))
242 (defun ez-remove-obj (obj)
243 (let ((parent (ez-get-obj-parent obj))
244 (sibling (ez-get-obj-sibling obj)))
246 (let ((child (ez-get-obj-child parent)))
248 (ez-set-obj-child parent sibling)
249 (while (not (= obj (ez-get-obj-sibling child)))
250 (setq child (ez-get-obj-sibling child)))
251 (ez-set-obj-sibling child (ez-get-obj-sibling obj))))
252 (ez-set-obj-parent obj 0))
253 (ez-set-obj-sibling obj 0)))
255 (defun ez-insert-obj (obj new-parent)
257 (unless (= new-parent 0)
258 (ez-set-obj-sibling obj (ez-get-obj-child new-parent))
259 (ez-set-obj-child new-parent obj)))
263 (defvar ez-zstring-alphabets
266 (list " abcdefghijklmnopqrstuvwxyz"
267 " ABCDEFGHIJKLMNOPQRSTUVWXYZ"
268 " \n0123456789.,!?_#'\"/\\-:()")
269 "Alphabets used by V3")
271 (defun ez-parse-zstring-word (word)
273 (logand (lsh word -10) #b11111)
274 (logand (lsh word -5) #b11111)
275 (logand word #b11111)))
277 (defun ez-get-zstring-chars-and-length (base-addr)
278 (let ((addr base-addr)
283 (let ((components (ez-parse-zstring-word (ez-mem-ref-word addr))))
284 (setq chars (append chars (cdr components)))
285 (setq addr (+ addr 2))
286 (setq word-count (+ word-count 1))
287 (when (= (car components) 1)
288 (setq not-done nil))))
289 (cons word-count chars)))
291 (defun ez-get-zstring-and-length (base-addr)
292 (let* ((word-count-and-chars (ez-get-zstring-chars-and-length base-addr))
293 (word-count (car word-count-and-chars))
294 (chars (cdr word-count-and-chars))
298 (while (> (length chars) 0)
299 (let ((char (pop chars)))
301 ((memq char '(1 2 3)) ;Abbreviation
302 (let* ((abbrev-char char)
304 (* 2 (ez-mem-ref-word (+ ez-abbrevtab-addr
305 (* 2 (+ (* (- abbrev-char 1) 32) (pop chars))))))))
306 (setq s (concat s (cdr (ez-get-zstring-and-length abbrev-addr))))))
308 (setq cur (mod (+ cur 1) 3)))
310 (setq cur (mod (+ 3 (- cur 1)) 3)))
311 ((and (= cur 2) (= char 6))
312 (setq s (concat s (char-to-string (+ (lsh (pop chars) 5) (pop chars)))))
315 (setq s (concat s (substring (elt ez-zstring-alphabets cur)
318 (cons word-count s)))
320 (defun ez-get-zstring (base-addr)
321 (cdr (ez-get-zstring-and-length base-addr)))
325 (defun ez-get-dictionary ()
326 (let* ((nseps (ez-mem-ref-byte ez-dict-base))
328 (mapcar (lambda (i) (ez-mem-ref-byte (+ ez-dict-base i)))
329 (number-sequence 1 nseps)))
330 (bytes-per-entry (ez-mem-ref-byte (+ ez-dict-base 1 nseps)))
331 (nentries (ez-mem-ref-word (+ ez-dict-base 1 nseps 1)))
332 (entries-base (+ ez-dict-base nseps 4))
334 (dotimes (i nentries)
335 (let ((this-base (+ entries-base (* 7 i))))
336 (setq entries (cons (cons this-base
337 (ez-get-zstring this-base))
339 (list entries separators entries)))
343 (defvar ez-call-stack nil)
345 (defun ez-make-call-stack-frame (pc &optional call-method)
351 (defun ez-add-call-stack-frame (pc &optional call-method)
352 (push (ez-make-call-stack-frame pc call-method) ez-call-stack))
354 (defun ez-pop-call-stack-frame ()
357 (defun ez-routine-stack ()
358 (elt (car ez-call-stack) 1))
360 (defun ez-routine-stack-push (val)
361 (let ((frame (car ez-call-stack)))
362 (ez-debug-message "\tPushed %x to stack" val)
363 (setf (elt frame 1) (cons val (elt frame 1)))))
365 (defun ez-routine-stack-pop ()
366 (let* ((frame (car ez-call-stack))
367 (rs-head (car (elt frame 1))))
368 (setf (elt frame 1) (cdr (elt frame 1)))
369 (ez-debug-message "\tPopped %x from stack" rs-head)
372 (defun ez-get-local-var (lvar)
373 (let* ((frame (car ez-call-stack))
374 (val (aref (elt frame 2) (- lvar 1))))
375 (ez-debug-message "\tRetrieved value %x from local variable %x" val lvar)
378 (defun ez-set-local-var (lvar val)
379 (let ((frame (car ez-call-stack)))
380 (ez-debug-message "\tSet local variable %x to %x" lvar val)
381 (aset (elt frame 2) (- lvar 1) val)))
384 (caar ez-call-stack))
386 (defun ez-set-pc (new-pc)
387 (setf (car (car ez-call-stack)) new-pc))
389 (defun ez-increment-pc (inc)
390 (ez-set-pc (+ (ez-get-pc) inc)))
392 (defun ez-read-pc-byte-and-inc ()
393 (let ((res (ez-mem-ref-byte (ez-get-pc))))
397 (defun ez-read-pc-word-and-inc ()
398 (let ((res (ez-mem-ref-word (ez-get-pc))))
402 ;; Instruction execution
404 (defun ez-get-var (var)
407 (ez-routine-stack-pop))
409 (ez-get-local-var var))
411 (ez-get-global-var (- var 16)))))
413 (defun ez-set-var (var val)
416 (ez-routine-stack-push val))
418 (ez-set-local-var var val))
420 (ez-set-global-var (- var 16) val))))
422 (defun ez-read-pc-var-and-inc ()
423 (ez-get-var (ez-read-pc-byte-and-inc)))
425 (defun ez-execute-instr ()
426 (let ((instr-pc (ez-get-pc))
427 (opbyte (ez-read-pc-byte-and-inc))
428 (optype) (opcode) (operands))
430 ((<= #x0 opbyte #x1f)
433 operands (list (ez-read-pc-byte-and-inc)
434 (ez-read-pc-byte-and-inc))
435 operand-types '(b b)))
436 ((<= #x20 opbyte #x3F)
438 opcode (- opbyte #x20)
439 operands (list (ez-read-pc-byte-and-inc)
440 (ez-read-pc-var-and-inc))
441 operand-types '(b w)))
442 ((<= #x40 opbyte #x5F)
444 opcode (- opbyte #x40)
445 operands (list (ez-read-pc-var-and-inc)
446 (ez-read-pc-byte-and-inc))
447 operand-types '(w b)))
448 ((<= #x60 opbyte #x7F)
450 opcode (- opbyte #x60)
451 operands (list (ez-read-pc-var-and-inc)
452 (ez-read-pc-var-and-inc))
453 operand-types '(w w)))
454 ((<= #x80 opbyte #x8F)
456 opcode (- opbyte #x80)
457 operands (list (ez-read-pc-word-and-inc))
459 ((<= #x90 opbyte #x9F)
461 opcode (- opbyte #x90)
462 operands (list (ez-read-pc-byte-and-inc))
464 ((<= #xA0 opbyte #xAF)
466 opcode (- opbyte #xa0)
467 operands (list (ez-read-pc-var-and-inc))
469 ((<= #xB0 opbyte #xBF)
471 opcode (- opbyte #xb0)
474 ((<= #xC0 opbyte #xDF)
476 opcode (- opbyte #xc0))
477 (let ((operands-and-types (ez-read-var-operands-and-inc)))
478 (setq operands (car operands-and-types)
479 operand-types (cdr operands-and-types))))
480 ((<= #xE0 opbyte #xFF)
482 opcode (- opbyte #xe0))
483 (let ((operands-and-types (ez-read-var-operands-and-inc)))
484 (setq operands (car operands-and-types)
485 operand-types (cdr operands-and-types)))))
486 (let ((table-row (assoc (list optype opcode) ez-op-table)))
488 (error "Unsupported op PC:%x Optype:%s Opcode:%x Operands:%s Operand-types:%s"
489 instr-pc optype opcode (ez-list-to-string-hex operands) operand-types))
490 (let ((mnemonic (elt table-row 1)))
491 (ez-debug-message "PC:%x Optype:%s Opcode:%x Mnemonic:%s Operands:%s Operand-types:%s"
492 instr-pc optype opcode mnemonic
493 (ez-list-to-string-hex operands) operand-types))
494 (funcall (elt table-row 2) operands operand-types))))
496 (defun ez-read-var-operands-and-inc ()
497 (let* ((type-byte (ez-read-pc-byte-and-inc))
498 (types (let ((type1 (lsh type-byte -6)))
502 (let ((type2 (mod (lsh type-byte -4) 4)))
506 (let ((type3 (mod (lsh type-byte -2) 4)))
510 (let ((type4 (mod type-byte 4)))
513 (list type4))))))))))))))
518 ((= type 0) (ez-read-pc-word-and-inc))
519 ((= type 1) (ez-read-pc-byte-and-inc))
520 ((= type 2) (ez-read-pc-var-and-inc))))
531 (defun ez-do-branch (branch)
532 (let* ((branch-byte (ez-read-pc-byte-and-inc))
533 (invert (= 0 (logand branch-byte #b10000000)))
534 (single-byte (> (logand branch-byte #b01000000) 0))
537 (logand branch-byte #b00111111)
538 (let ((pos (= (logand branch-byte #b00100000) 0))
539 (val (+ (* 256 (logand branch-byte #b00011111))
540 (ez-read-pc-byte-and-inc))))
544 (if (or (and branch (not invert))
545 (and (not branch) invert))
552 (ez-set-pc (+ (ez-get-pc) offset -2)))))))
557 '(((0op #x00) rtrue ez-op-rtrue)
558 ((0op #x01) rfalse ez-op-rfalse)
559 ((1op #x00) jz ez-op-jz)
560 ((1op #x05) inc ez-op-inc)
561 ((1op #x06) dec ez-op-dec)
562 ((1op #x0B) ret ez-op-ret)
563 ((0op #x08) ret_pulled ez-op-ret-pulled)
564 ((1op #x0C) jump ez-op-jump)
565 ((2op #x05) inc_jg ez-op-inc-jg)
566 ((2op #x04) dec_jg ez-op-dec-jg)
567 ((2op #x0D) store ez-op-store)
568 ((1op #x0E) load ez-op-load)
569 ((var #x01) storew ez-op-storew)
570 ((2op #x0F) loadw ez-op-loadw)
571 ((var #x02) storeb ez-op-storeb)
572 ((2op #x10) loadb ez-op-loadb)
573 ((2op #x01) je ez-op-je)
574 ((2op #x02) jl ez-op-jl)
575 ((2op #x03) jg ez-op-jg)
576 ((2op #x06) jin ez-op-jin)
577 ((2op #x07) test ez-op-test)
578 ((2op #x08) or ez-op-or)
579 ((2op #x09) and ez-op-and)
580 ((2op #x14) add ez-op-add)
581 ((2op #x15) sub ez-op-sub)
582 ((2op #x16) mul ez-op-mul)
583 ((2op #x17) div ez-op-div)
584 ((2op #x18) mod ez-op-mod)
585 ((var #x00) call_fv ez-op-callfv)
586 ((1op #x01) get_sibling ez-op-get-sibling)
587 ((1op #x02) get_child ez-op-get-child)
588 ((1op #x03) get_parent ez-op-get-parent)
589 ((2op #x0A) test_attr ez-op-test-attr)
590 ((2op #x0B) set_attr ez-op-set-attr)
591 ((2op #x0C) clear_attr ez-op-clear-attr)
592 ((1op #x09) remove_obj ez-op-remove-obj)
593 ((2op #x0E) insert_obj ez-op-insert-obj)
594 ((var #x03) put_prop ez-op-put-prop)
595 ((2op #x11) get_prop ez-op-get-prop)
596 ((0op #x02) print ez-op-print)
597 ((0op #x0B) new_line ez-op-new-line)
598 ((var #x06) print_num ez-op-print-num)
599 ((var #x05) print_char ez-op-print-char)
600 ((1op #x0A) print_obj ez-op-print-obj)
601 ((var #x04) read ez-op-read)))
603 (defun ez-op-ret (operands &optional operand-types)
604 (let ((retval (car operands)))
605 (ez-debug-message "\tReturning value %x" retval)
606 (ez-pop-call-stack-frame)
607 (ez-set-var (ez-read-pc-byte-and-inc) retval))
610 (defun ez-op-ret-pulled (operands operand-types)
611 (let ((retval (ez-routine-stack-pop)))
612 (ez-debug-message "\tReturning value %x" retval)
613 (ez-op-ret (list retval)))
616 (defun ez-op-rtrue (&optional operands operand-types)
620 (defun ez-op-rfalse (&optional operands operand-types)
624 (defun ez-op-jz (operands operand-types)
625 (ez-do-branch (= (car operands) 0))
628 (defun ez-op-je (operands operand-types)
629 (ez-do-branch (memq (car operands) (cdr operands)))
632 (defun ez-op-jg (operands operand-types)
633 (let ((s1 (ez-decode-signed-operand (car operands) (car operand-types)))
634 (s2 (ez-decode-signed-operand (cadr operands) (cadr operand-types))))
635 (ez-do-branch (> s1 s2)))
638 (defun ez-op-jl (operands operand-types)
639 (let ((s1 (ez-decode-signed-operand (car operands) (car operand-types)))
640 (s2 (ez-decode-signed-operand (cadr operands) (cadr operand-types))))
641 (ez-do-branch (< s1 s2)))
644 (defun ez-op-inc-jg (operands operand-types)
645 (let ((var (car operands)))
646 (ez-op-inc (list var))
647 (ez-op-jg (cons (ez-get-var var) (cdr operands)) (cons 'w (cdr operand-types))))
650 (defun ez-op-dec-jl (operands operand-types)
651 (let ((var (car operands)))
652 (ez-op-dec (list var))
653 (ez-op-jl (cons (ez-get-var var) (cdr operands)) (cons 'w (cdr operand-types))))
656 (defun ez-op-jin (operands operand-types)
657 (let ((obj (car operands))
659 (ez-do-branch (or (= n 0)
660 (= n (ez-get-obj-parent obj)))))
663 (defun ez-op-test (operands operand-types)
664 (let ((a (car operands))
666 (ez-do-branch (= (logand a b) b)))
669 (defun ez-op-jump (operands operand-types)
670 (let ((offset (if (eq (car operand-types) 'b)
671 (ez-decode-signed-byte (car operands))
672 (ez-decode-signed-word (car operands)))))
673 (ez-set-pc (+ (ez-get-pc) offset -2)))
676 (defun ez-op-inc (operands &optional operand-types)
677 (let ((var (car operands)))
678 (ez-set-var var (mod (+ 1 (ez-get-var var)) #x10000)))
681 (defun ez-op-dec (operands &optional operand-types)
682 (let ((var (car operands)))
683 (ez-set-var var (mod (+ (ez-get-var var) 1) #x10000)))
686 (defun ez-op-store (operands operand-types)
687 (let ((var (car operands))
692 (defun ez-op-load (operands operand-types)
693 (let ((var (car operands)))
694 (ez-set-var (ez-read-pc-byte-and-inc) (ez-get-var var)))
697 (defun ez-op-storew (operands operand-types)
698 (let ((baddr (car operands))
700 (a (caddr operands)))
701 (ez-mem-set-word (+ baddr (* 2 n)) a))
704 (defun ez-op-loadw (operands operand-types)
705 (let ((baddr (car operands))
707 (ez-set-var (ez-read-pc-byte-and-inc) (ez-mem-ref-word (+ baddr (* 2 n)))))
710 (defun ez-op-storeb (operands operand-types)
711 (let ((baddr (car operands))
713 (a (caddr operands)))
714 (ez-mem-set-byte (+ baddr n) a))
717 (defun ez-op-loadb (operands operand-types)
718 (let ((baddr (car operands))
720 (ez-set-var (ez-read-pc-byte-and-inc) (ez-mem-ref-byte (+ baddr n))))
723 (defun ez-op-and (operands operand-types)
724 (let ((a (car operands))
726 (ez-set-var (ez-read-pc-byte-and-inc) (logand a b)))
729 (defun ez-op-or (operands operand-types)
730 (let ((a (car operands))
732 (ez-set-var (ez-read-pc-byte-and-inc) (logior a b)))
735 (defun ez-op-add (operands operand-types)
736 (let ((a (car operands))
738 (ez-set-var (ez-read-pc-byte-and-inc) (mod (+ a b) #x10000)))
741 (defun ez-op-sub (operands operand-types)
742 (let ((a (car operands))
744 (ez-set-var (ez-read-pc-byte-and-inc) (mod (+ (- a b) #x10000) #x10000)))
747 (defun ez-op-mul (a b)
748 (let ((a (car operands))
750 (ez-set-var (ez-read-pc-byte-and-inc) (mod (* a b) #x10000)))
753 (defun ez-op-div (a b)
754 (error "Not implemented"))
756 (defun ez-op-mod (a b)
757 (error "Not implemented"))
759 (defun ez-op-callfv (operands operand-types)
760 (let* ((raddr (car operands))
761 (call-operands (cdr operands))
763 (L (ez-mem-ref-byte r))
764 (n (length call-operands))
765 (new-pc (+ r 1 (* L 2))))
767 (ez-set-var (ez-read-pc-byte-and-inc) 0) ; Simply return 0
768 (ez-add-call-stack-frame new-pc)
771 (ez-set-local-var (+ i 1) (elt call-operands i))
772 (ez-set-local-var (+ i 1) (ez-mem-ref-word (+ r 1 (* 2 i))))))))
775 (defun ez-op-test-attr (operands operand-types)
776 (let ((obj (car operands))
777 (attr (cadr operands)))
778 (ez-do-branch (= 1 (ez-get-obj-attr obj attr)))
781 (defun ez-op-set-attr (operands operand-types)
782 (let ((obj (car operands))
783 (attr (cadr operands)))
784 (ez-set-obj-attr obj attr 1))
787 (defun ez-op-clear-attr (operands operand-types)
788 (let ((obj (car operands))
789 (attr (cadr operands)))
790 (ez-set-obj-attr obj attr 0))
793 (defun ez-op-get-sibling (operands operand-types)
794 (let ((sib (ez-get-obj-sibling (car operands))))
795 (ez-set-var (ez-read-pc-byte-and-inc) sib)
796 (ez-do-branch (> sib 0)))
799 (defun ez-op-get-child (operands operand-types)
800 (let ((child (ez-get-obj-child (car operands))))
801 (ez-set-var (ez-read-pc-byte-and-inc) child)
802 (ez-do-branch (> child 0)))
805 (defun ez-op-get-parent (operands operand-types)
806 (let ((parent (ez-get-obj-parent (car operands))))
807 (ez-set-var (ez-read-pc-byte-and-inc) parent))
810 (defun ez-op-remove-obj (operands operand-types)
811 (let ((obj (car operands)))
815 (defun ez-op-insert-obj (operands operand-types)
816 (let ((obj1 (car operands))
817 (obj2 (cadr operands)))
818 (ez-insert-obj obj1 obj2))
821 (defun ez-op-put-prop (operands operand-types)
822 (let* ((obj (car operands))
823 (prop (cadr operands))
824 (a (caddr operands)))
825 (ez-set-obj-prop obj prop a))
828 (defun ez-op-get-prop (operands operand-types)
829 (let* ((obj (car operands))
830 (prop (cadr operands)))
831 (ez-set-var (ez-read-pc-byte-and-inc)
832 (ez-get-obj-prop obj prop)))
835 (defun ez-op-print (operands operand-types)
836 (let* ((word-count-and-string (ez-get-zstring-and-length (ez-get-pc)))
837 (word-count (car word-count-and-string))
838 (string (cdr word-count-and-string)))
840 (ez-increment-pc (* 2 word-count)))
843 (defun ez-op-new-line (operands operand-types)
847 (defun ez-op-print-num (operands operand-types)
848 (let ((s (ez-decode-signed-operand (car operands) (car operand-types))))
849 (ez-print (number-to-string s)))
852 (defun ez-op-print-char (operands operand-types)
853 (let ((c (car operands)))
854 (ez-print (string c)))
857 (defun ez-op-print-obj (operands operand-types)
858 (let ((obj (car operands)))
859 (ez-print (ez-get-obj-name obj)))
862 (defvar ez--next-read-args nil)
863 (defun ez-op-read (operands operand-types)
864 (let ((baddr1 (car operands))
865 (baddr2 (cadr operands)))
866 (setq ez--next-read-args (list baddr1 baddr2)))
869 (defun ez-op-read2 (input-string)
870 (let ((baddr1 (car ez--next-read-args))
871 (baddr2 (cadr ez--next-read-args)))
873 (dotimes (i (length input-string))
874 (ez-mem-set-byte (+ baddr1 1 i) (downcase (elt input-string i))))
875 (ez-mem-set-byte (+ baddr1 1 (length input-string)) 0)
881 (defun ez-load-and-run (filename)
882 (ez-load-file filename)
884 (setq ez-call-stack (list (ez-make-call-stack-frame ez-start-pc)))
888 (defvar ez-machine-state nil
889 "Identifies the current executation state of the Z-machine.")
892 (setq ez-machine-state 'run)
893 (while (eq ez-machine-state 'run)
894 (setq ez-machine-state (ez-execute-instr))))
899 (defvar ez-input-marker nil
900 "Marker for input position in buffer.")
902 (defun ez-setup-buffer ()
903 (with-current-buffer (get-buffer-create "*ez*")
905 (let ((inhibit-read-only t))
907 (setq-local scroll-conservatively 1)
908 (if (markerp ez-input-marker)
909 (set-marker ez-input-marker (point-max))
910 (setq ez-input-marker (point-max-marker)))
911 (goto-char (point-max))))
914 (defun ez-print (string)
915 (with-current-buffer "*ez*"
917 (goto-char ez-input-marker)
918 (insert-before-markers string))))
922 (if (not (eq ez-machine-state 'wait-for-input))
923 (error "Z-machine not ready for input."))
924 (let ((input-string (with-current-buffer "*ez*"
925 (buffer-substring ez-input-marker (point-max)))))
926 (delete-region ez-input-marker (point-max))
927 (ez-print (concat input-string "\n"))
928 (ez-debug-message "\tReceived string \"%s\"" input-string)
929 (ez-op-read2 input-string)
934 (defun ez-setup-debug-buffer ()
935 (with-current-buffer (get-buffer-create "*ez-debug-trace*")
936 (setq-local buffer-read-only t)
937 (let ((inhibit-read-only t))
939 (insert "--- Trace Start ---\n\n"))))
941 (defun ez-debug-message (&rest strings)
942 (with-current-buffer (get-buffer-create "*ez-debug-trace*")
944 (goto-char (point-max))
945 (let ((inhibit-read-only t))
946 (insert (apply #'format-message strings) "\n")))))
948 (defun ez-debug-memory ()
950 (with-current-buffer (get-buffer-create "*ez-debug-memory*")
951 (setq-local buffer-read-only t)
952 (let ((inhibit-read-only t)
957 (setq-local buffer-undo-list nil)
959 (goto-char old-point))))
964 (let ((map (make-sparse-keymap)))
965 (define-key map (kbd "RET") 'ez-enter)
968 (define-derived-mode ez-mode text-mode "ez"
969 "Major mode for EZ.")
971 (when (fboundp 'evil-set-initial-state)
972 (evil-set-initial-state 'ez-mode 'insert))
975 (interactive "fEnter name of z3 story file: ")
976 (if (get-buffer "*ez*")
977 (switch-to-buffer "*ez*")
978 (switch-to-buffer "*ez*")
980 (ez-load-and-run zfile))
986 (ez-setup-debug-buffer)
987 (ez-load-and-run "zork1.z3"))