X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?a=blobdiff_plain;f=ez.el;h=f96005a3167b302367d40e8a22545fc830c4e593;hb=c2bf7428388aedee98c42c52c3c1bf2ac75f29bc;hp=1efc2d672c8a2205e956b5641d5795522472ad12;hpb=b1e6b624739552c19cd4c3b033716360fda64e94;p=ez.git

diff --git a/ez.el b/ez.el
index 1efc2d6..f96005a 100644
--- a/ez.el
+++ b/ez.el
@@ -26,6 +26,13 @@
 
 ;;; Commentary:
 
+;; There are many Z-machine interpreters, but this one is mine.
+;; It only capable of interpreting the subset of Z-code necessary
+;; to run the first Zork game in z3 format.
+;;
+;; It is based entirely on the description of the Z-machine contained
+;; Marnix Klooster's wonderful document, "The Z-machine And How to Emulate It."
+
 ;;; Code:
 
 ;; Utility functions
@@ -55,6 +62,14 @@
         new-s
       (binformat d new-s))))
 
+(defun ez-list-to-string-hex (l)
+  (concat "("
+          (when l
+            (concat
+             (format "%x" (car l))
+             (apply 'concat (mapcar (lambda (n) (format " %x" n)) (cdr l)))))
+          ")"))
+
 ;; Memory
 
 (defvar ez-memory nil
@@ -106,10 +121,14 @@
 (defun ez-get-global-var (gvar)
   (if (> gvar 239)
       (error "Invalid global variable %d" gvar))
-  (ez-mem-ref-word (+ (* 2 gvar) ez-globalvartab-addr)))
+  (let ((val
+         (ez-mem-ref-word (+ (* 2 gvar) ez-globalvartab-addr))))
+    (message "\tRetrieved %x from global variable %x" val gvar)
+    val))
 
 (defun ez-set-global-var (gvar val)
-  (ez-mem-set-word (+ (* 2 gvar) ez-globalvartab-addr) val))
+  (ez-mem-set-word (+ (* 2 gvar) ez-globalvartab-addr) val)
+  (message "\tSet global variabl %x to %x" gvar val))
 
 ;; Object tree
 
@@ -147,14 +166,14 @@
   (let ((addr (ez-get-obj-addr obj)))
     (ez-mem-set-byte (+ addr 6) new-child)))
 
-(defun ez-get-obj-plist-addr (obj-id)
-  (let ((addr (ez-get-obj-addr obj-id)))
+(defun ez-get-obj-plist-addr (obj)
+  (let ((addr (ez-get-obj-addr obj)))
     (ez-mem-ref-word (+ addr 7))))
 
-(defun ez-get-obj-name (obj-id)
-  (let ((plist-addr (ez-get-obj-plist-addr obj-id)))
+(defun ez-get-obj-name (obj)
+  (let ((plist-addr (ez-get-obj-plist-addr obj)))
     (if (> (ez-mem-ref-byte plist-addr) 0)
-        (ez-get-zstring (+ 1 (ez-get-obj-plist-addr obj-id)))
+        (ez-get-zstring (+ 1 (ez-get-obj-plist-addr obj)))
       nil)))
 
 (defun ez-get-prop-default (prop)
@@ -300,7 +319,6 @@
 (defun ez-get-zstring (base-addr)
   (cdr (ez-get-zstring-and-length base-addr)))
 
-
 ;; Call stack
 
 (defvar ez-call-stack nil)
@@ -322,20 +340,25 @@
 
 (defun ez-routine-stack-push (val)
   (let ((frame (car ez-call-stack)))
+    (message "\tPushed %x to stack" val)
     (setf (elt frame 1) (cons val (elt frame 1)))))
 
 (defun ez-routine-stack-pop ()
   (let* ((frame (car ez-call-stack))
          (rs-head (car (elt frame 1))))
     (setf (elt frame 1) (cdr (elt frame 1)))
+    (message "\tPopped %x from stack" rs-head)
     rs-head))
 
 (defun ez-get-local-var (lvar)
-  (let ((frame (car ez-call-stack)))
-    (aref (elt frame 2) (- lvar 1))))
+  (let* ((frame (car ez-call-stack))
+         (val (aref (elt frame 2) (- lvar 1))))
+    (message "\tRetrieved value %x from local variable %x" val lvar)
+    val))
 
 (defun ez-set-local-var (lvar val)
   (let ((frame (car ez-call-stack)))
+    (message "\tSet local variable %x to %x" lvar val)
     (aset (elt frame 2) (- lvar 1) val)))
 
 (defun ez-get-pc ()
@@ -444,10 +467,11 @@
     (let ((table-row (assoc (list optype opcode) ez-op-table)))
       (unless table-row
         (error "Unsupported op PC:%x Optype:%s Opcode:%x Operands:%s Operand-types:%s"
-               instr-pc optype opcode operands operand-types))
+               instr-pc optype opcode (ez-list-to-string-hex operands) operand-types))
       (let ((mnemonic (elt table-row 1)))
         (message "PC:%x Optype:%s Opcode:%x Mnemonic:%s Operands:%s Operand-types:%s"
-                 instr-pc optype opcode mnemonic operands operand-types))
+                 instr-pc optype opcode mnemonic
+                 (ez-list-to-string-hex operands) operand-types))
       (funcall (elt table-row 2) operands operand-types))))
 
 (defun ez-read-var-operands-and-inc ()
@@ -456,15 +480,15 @@
                   (if (= type1 #b11)
                       nil
                     (cons type1
-                          (let ((type2 (lsh (logand #b110000 type-byte) -4)))
+                          (let ((type2 (mod (lsh type-byte -4) 4)))
                             (if (= type2 #b11)
                                 nil
                               (cons type2
-                                    (let ((type3 (lsh (logand #b1100 type-byte) -2)))
+                                    (let ((type3 (mod (lsh type-byte -2) 4)))
                                       (if (= type3 #b11)
                                           nil
                                         (cons type3
-                                              (let ((type4 (logand #b11)))
+                                              (let ((type4 (mod type-byte 4)))
                                                 (if (= type4 #b11)
                                                     nil
                                                   (list type4))))))))))))))
@@ -517,6 +541,7 @@
     ((1op #x05) inc ez-op-inc)
     ((1op #x06) dec ez-op-dec)
     ((1op #x0B) ret ez-op-ret)
+    ((0op #x08) ret_pulled ez-op-ret-pulled)
     ((1op #x0C) jump ez-op-jump)
     ((2op #x05) inc_jg ez-op-inc-jg)
     ((2op #x04) dec_jg ez-op-dec-jg)
@@ -527,6 +552,10 @@
     ((var #x02) storeb ez-op-storeb)
     ((2op #x10) loadb ez-op-loadb)
     ((2op #x01) je ez-op-je)
+    ((2op #x02) jl ez-op-jl)
+    ((2op #x03) jg ez-op-jg)
+    ((2op #x06) jin ez-op-jin)
+    ((2op #x07) test ez-op-test)
     ((2op #x08) or ez-op-or)
     ((2op #x09) and ez-op-and)
     ((2op #x14) add ez-op-add)
@@ -534,7 +563,7 @@
     ((2op #x16) mul ez-op-mul)
     ((2op #x17) div ez-op-div)
     ((2op #x18) mod ez-op-mod)
-    ((var #x00) call_fv ez-op-callf)
+    ((var #x00) call_fv ez-op-callfv)
     ((1op #x01) get_sibling ez-op-get-sibling)
     ((1op #x02) get_child ez-op-get-child)
     ((1op #x03) get_parent ez-op-get-parent)
@@ -544,141 +573,163 @@
     ((1op #x09) remove_obj ez-op-remove-obj)
     ((2op #x0E) insert_obj ez-op-insert-obj)
     ((var #x03) put_prop ez-op-put-prop)
+    ((2op #x11) get_prop ez-op-get-prop)
     ((0op #x02) print ez-op-print)
     ((0op #x0B) new_line ez-op-new-line)
     ((var #x06) print_num ez-op-print-num)
-    ((var #x05) print_char ez-op-print-char)))
+    ((var #x05) print_char ez-op-print-char)
+    ((1op #x0A) print_obj ez-op-print-obj)
+    ((var #x04) read ez-op-read)))
 
 (defun ez-op-ret (operands &optional operand-types)
   (let ((retval (car operands)))
+    (message "\tReturning value %x" retval)
     (ez-pop-call-stack-frame)
     (ez-set-var (ez-read-pc-byte-and-inc) retval))
-  t)
+  'run)
+
+(defun ez-op-ret-pulled (operands operand-types)
+  (let ((retval (ez-routine-stack-pop)))
+    (message "\tReturning value %x" retval)
+    (ez-op-ret (list retval)))
+  'run)
 
 (defun ez-op-rtrue (&optional operands operand-types)
   (ez-op-ret (list 1))
-  t)
+  'run)
 
 (defun ez-op-rfalse (&optional operands operand-types)
   (ez-op-ret (list 0))
-  t)
+  'run)
 
 (defun ez-op-jz (operands operand-types)
   (ez-do-branch (= (car operands) 0))
-  t)
+  'run)
 
 (defun ez-op-je (operands operand-types)
   (ez-do-branch (memq (car operands) (cdr operands)))
-  t)
+  'run)
 
 (defun ez-op-jg (operands operand-types)
   (let ((s1 (ez-decode-signed-operand (car operands) (car operand-types)))
         (s2 (ez-decode-signed-operand (cadr operands) (cadr operand-types))))
     (ez-do-branch (> s1 s2)))
-  t)
+  'run)
 
 (defun ez-op-jl (operands operand-types)
   (let ((s1 (ez-decode-signed-operand (car operands) (car operand-types)))
         (s2 (ez-decode-signed-operand (cadr operands) (cadr operand-types))))
     (ez-do-branch (< s1 s2)))
-  t)
+  'run)
 
 (defun ez-op-inc-jg (operands operand-types)
   (let ((var (car operands)))
     (ez-op-inc (list var))
     (ez-op-jg (cons (ez-get-var var) (cdr operands)) (cons 'w (cdr operand-types))))
-  t)
+  'run)
 
 (defun ez-op-dec-jl (operands operand-types)
   (let ((var (car operands)))
     (ez-op-dec (list var))
     (ez-op-jl (cons (ez-get-var var) (cdr operands)) (cons 'w (cdr operand-types))))
-  t)
+  'run)
 
+(defun ez-op-jin (operands operand-types)
+  (let ((obj (car operands))
+        (n (cadr operands)))
+    (ez-do-branch (or (= n 0)
+                      (= n (ez-get-obj-parent obj)))))
+  'run)
+
+(defun ez-op-test (operands operand-types)
+  (let ((a (car operands))
+        (b (cadr operands)))
+    (ez-do-branch (= (logand a b) b)))
+  'run)
 
 (defun ez-op-jump (operands operand-types)
   (let ((offset (if (eq (car operand-types) 'b)
                     (ez-decode-signed-byte (car operands))
                   (ez-decode-signed-word (car operands)))))
     (ez-set-pc (+ (ez-get-pc) offset -2)))
-  t)
+  'run)
 
 (defun ez-op-inc (operands &optional operand-types)
   (let ((var (car operands)))
     (ez-set-var var (mod (+ 1 (ez-get-var var)) #x10000)))
-  t)
+  'run)
 
 (defun ez-op-dec (operands &optional operand-types)
   (let ((var (car operands)))
     (ez-set-var var (mod (+ (ez-get-var var) 1) #x10000)))
-  t)
+  'run)
 
 (defun ez-op-store (operands operand-types)
   (let ((var (car operands))
         (a (cadr operands)))
     (ez-set-var var a))
-  t)
+  'run)
 
 (defun ez-op-load (operands operand-types)
   (let ((var (car operands)))
     (ez-set-var (ez-read-pc-byte-and-inc) (ez-get-var var)))
-  t)
+  'run)
 
 (defun ez-op-storew (operands operand-types)
   (let ((baddr (car operands))
         (n (cadr operands))
         (a (caddr operands)))
     (ez-mem-set-word (+ baddr (* 2 n)) a))
-  t)
+  'run)
 
 (defun ez-op-loadw (operands operand-types)
   (let ((baddr (car operands))
         (n (cadr operands)))
     (ez-set-var (ez-read-pc-byte-and-inc) (ez-mem-ref-word (+ baddr (* 2 n)))))
-  t)
+  'run)
 
 (defun ez-op-storeb (operands operand-types)
   (let ((baddr (car operands))
         (n (cadr operands))
         (a (caddr operands)))
     (ez-mem-set-byte (+ baddr n) a))
-  t)
+  'run)
 
 (defun ez-op-loadb (operands operand-types)
   (let ((baddr (car operands))
         (n (cadr operands)))
     (ez-set-var (ez-read-pc-byte-and-inc) (ez-mem-ref-byte (+ baddr n))))
-  t)
+  'run)
 
 (defun ez-op-and (operands operand-types)
   (let ((a (car operands))
         (b (cadr operands)))
     (ez-set-var (ez-read-pc-byte-and-inc) (logand a b)))
-  t)
+  'run)
 
 (defun ez-op-or (operands operand-types)
   (let ((a (car operands))
         (b (cadr operands)))
     (ez-set-var (ez-read-pc-byte-and-inc) (logior a b)))
-  t)
+  'run)
 
 (defun ez-op-add (operands operand-types)
   (let ((a (car operands))
         (b (cadr operands)))
     (ez-set-var (ez-read-pc-byte-and-inc) (mod (+ a b) #x10000)))
-  t)
+  'run)
 
 (defun ez-op-sub (operands operand-types)
   (let ((a (car operands))
         (b (cadr operands)))
     (ez-set-var (ez-read-pc-byte-and-inc) (mod (+ (- a b) #x10000) #x10000)))
-  t)
+  'run)
 
 (defun ez-op-mul (a b)
   (let ((a (car operands))
         (b (cadr operands)))
     (ez-set-var (ez-read-pc-byte-and-inc) (mod (* a b) #x10000)))
-  t)
+  'run)
 
 (defun ez-op-div (a b)
   (error "Not implemented"))
@@ -686,73 +737,81 @@
 (defun ez-op-mod (a b)
   (error "Not implemented"))
 
-(defun ez-op-callf (operands operand-types)
+(defun ez-op-callfv (operands operand-types)
   (let* ((raddr (car operands))
          (call-operands (cdr operands))
          (r (* 2 raddr))
          (L (ez-mem-ref-byte r))
          (n (length call-operands))
          (new-pc (+ r 1 (* L 2))))
-    (ez-add-call-stack-frame new-pc)
-    (dotimes (i L)
-      (if (< i n)
-          (ez-set-local-var (+ i 1) (elt call-operands i))
-        (ez-set-local-var (+ i 1) (ez-mem-ref-word (+ r 1 (* 2 i)))))))
-  t)
+    (if (= raddr 0)
+        (ez-set-var (ez-read-pc-byte-and-inc) 0) ; Simply return 0
+      (ez-add-call-stack-frame new-pc)
+      (dotimes (i L)
+        (if (< i n)
+            (ez-set-local-var (+ i 1) (elt call-operands i))
+          (ez-set-local-var (+ i 1) (ez-mem-ref-word (+ r 1 (* 2 i))))))))
+  'run)
 
 (defun ez-op-test-attr (operands operand-types)
   (let ((obj (car operands))
         (attr (cadr operands)))
     (ez-do-branch (= 1 (ez-get-obj-attr obj attr)))
-    t))
+    'run))
 
 (defun ez-op-set-attr (operands operand-types)
   (let ((obj (car operands))
         (attr (cadr operands)))
     (ez-set-obj-attr obj attr 1))
-  t)
+  'run)
 
 (defun ez-op-clear-attr (operands operand-types)
   (let ((obj (car operands))
         (attr (cadr operands)))
     (ez-set-obj-attr obj attr 0))
-  t)
+  'run)
 
 (defun ez-op-get-sibling (operands operand-types)
   (let ((sib (ez-get-obj-sibling (car operands))))
     (ez-set-var (ez-read-pc-byte-and-inc) sib)
-    (ez-do-branch (> sib 0))
-    t))
+    (ez-do-branch (> sib 0)))
+  'run)
 
 (defun ez-op-get-child (operands operand-types)
   (let ((child (ez-get-obj-child (car operands))))
     (ez-set-var (ez-read-pc-byte-and-inc) child)
-    (ez-do-branch (> child 0))
-    t))
+    (ez-do-branch (> child 0)))
+  'run)
 
 (defun ez-op-get-parent (operands operand-types)
   (let ((parent (ez-get-obj-parent (car operands))))
-    (ez-set-var (ez-read-pc-byte-and-inc) parent)
-    (ez-do-branch (> parent 0))
-    t))
+    (ez-set-var (ez-read-pc-byte-and-inc) parent))
+  'run)
 
 (defun ez-op-remove-obj (operands operand-types)
   (let ((obj (car operands)))
     (ez-remove-obj obj))
-  t)
+  'run)
 
 (defun ez-op-insert-obj (operands operand-types)
   (let ((obj1 (car operands))
         (obj2 (cadr operands)))
     (ez-insert-obj obj1 obj2))
-  t)
+  'run)
 
 (defun ez-op-put-prop (operands operand-types)
   (let* ((obj (car operands))
          (prop (cadr operands))
          (a (caddr operands)))
-    (ez-set-obj-prop obj prop a)
-    t))
+    (ez-set-obj-prop obj prop a))
+  'run)
+
+(defun ez-op-get-prop (operands operand-types)
+  (let* ((obj (car operands))
+         (prop (cadr operands)))
+    (ez-set-var (ez-read-pc-byte-and-inc)
+                (ez-get-obj-prop obj prop)))
+  'run)
 
 (defun ez-op-print (operands operand-types)
   (let* ((word-count-and-string (ez-get-zstring-and-length (ez-get-pc)))
@@ -760,84 +819,89 @@
          (string (cdr word-count-and-string)))
     (ez-print string)
     (ez-increment-pc (* 2 word-count)))
-  t)
+  'run)
 
 (defun ez-op-new-line (operands operand-types)
   (ez-print "\n")
-  t)
+  'run)
 
 (defun ez-op-print-num (operands operand-types)
   (let ((s (ez-decode-signed-operand (car operands) (car operand-types))))
     (ez-print (number-to-string s)))
-  t)
+  'run)
 
 (defun ez-op-print-char (operands operand-types)
   (let ((c (car operands)))
     (ez-print (string c)))
-  t)
+  'run)
 
+(defun ez-op-print-obj (operands operand-types)
+  (let ((obj (car operands)))
+    (ez-print (ez-get-obj-name obj)))
+  'run)
+
+(defvar ez--next-read-args nil)
+(defun ez-op-read (operands operand-types)
+  (let ((baddr1 (car operands))
+        (baddr2 (cadr operands)))
+    (setq ez--next-read-args (list baddr1 baddr2)))
+  'wait-for-input)
+
+(defun ez-op-read2 (input-string)
+  (ez-tokenize-string input-string
+                      (car ez--next-read-args)
+                      (cadr ez--next-read-args))
+  'run)
 
 ;; Execution loop
 
-(defun ez-run (filename)
+(defun ez-load-and-run (filename)
   (ez-load-file filename)
   (ez-parse-header)
   (setq ez-call-stack (list (ez-make-call-stack-frame ez-start-pc)))
 
-  (while (ez-execute-instr)))
+  (ez-run))
 
+(defvar ez-machine-state nil
+  "Identifies the current executation state of the Z-machine.")
+
+(defun ez-run ()
+  (setq ez-machine-state 'run)
+  (while (eq ez-machine-state 'run)
+    (setq ez-machine-state (ez-execute-instr))))
 
 ;;; Buffer and I/O
 ;;
 
-(defun ez-render-prompt ()
-  (with-current-buffer "*ez*"
-    (let ((update-point (= ez-input-marker (point)))
-          (update-window-points (mapcar (lambda (w)
-                                          (list (= (window-point w) ez-input-marker)
-                                                w))
-                                        (get-buffer-window-list nil nil t))))
-      (save-excursion
-        (set-marker-insertion-type ez-prompt-marker nil)
-        (set-marker-insertion-type ez-input-marker t)
-        (let ((inhibit-read-only t))
-          (delete-region ez-prompt-marker ez-input-marker)
-          (goto-char ez-prompt-marker)
-          (insert
-           ">"
-           (propertize " " ; Need this to be separate to mark it as rear-nonsticky
-                       'read-only t
-                       'rear-nonsticky t)))
-        (set-marker-insertion-type ez-input-marker nil))
-      (goto-char ez-input-marker))))
-
-(defvar ez-prompt-marker nil
-  "Marker for prompt position in buffer.")
-
 (defvar ez-input-marker nil
-  "Marker for prompt position in buffer.")
+  "Marker for input position in buffer.")
 
 (defun ez-setup-buffer ()
   (with-current-buffer (get-buffer-create "*ez*")
     (let ((inhibit-read-only t))
       (delete-region (point-min) (point-max)))
     (setq-local scroll-conservatively 1)
-    (if (markerp ez-prompt-marker)
-        (set-marker ez-prompt-marker (point-max))
-      (setq ez-prompt-marker (point-max-marker)))
     (if (markerp ez-input-marker)
         (set-marker ez-input-marker (point-max))
       (setq ez-input-marker (point-max-marker)))
-    (goto-char (point-max))
-    (ez-render-prompt)))
+    (goto-char (point-max))))
 
 
 (defun ez-print (string)
   (with-current-buffer "*ez*"
     (save-excursion
-      (goto-char ez-prompt-marker)
+      (goto-char ez-input-marker)
       (insert-before-markers string))))
 
+(defun ez-enter ()
+  (interactive)
+  (if (not (eq ez-machine-state 'wait-for-input))
+      (error "Z-machine not ready for input."))
+  (let ((input-string (with-current-buffer "*ez*"
+                        (buffer-substring ez-input-marker (point-max)))))
+    (ez-op-read2 input-string)
+    (ez-run)))
+
 ;; Mode
 
 (defvar ez-mode-map
@@ -858,7 +922,7 @@
     (switch-to-buffer "*ez*")
     (ez-mode)
     (ez-setup-buffer)
-    (ez-run zfile))
+    (ez-load-and-run zfile))
   "Started EZ.")
 
 (defun ez-debug ()
@@ -866,6 +930,6 @@
   (switch-to-buffer "*ez*")
   (ez-mode)
   (ez-setup-buffer)
-  (ez-run "zork1.z3"))
+  (ez-load-and-run "zork1.z3"))
 
 ;;; ez.el ends here