X-Git-Url: https://thelambdalab.xyz/gitweb/index.cgi?p=ez.git;a=blobdiff_plain;f=ez.el;h=af348a982f49420db40b407bda96f4819116140c;hp=ac409803eb15dccf3104958cc93abf2c4595df1b;hb=6a8f22a5f03a455c5cc4a6af1bfcbf117c9084ee;hpb=737aeafc9a89357b63b50c21d9f60def16cb7388

diff --git a/ez.el b/ez.el
index ac40980..af348a9 100644
--- a/ez.el
+++ b/ez.el
@@ -41,6 +41,11 @@
 (defun ez-decode-signed-word (w)
   (ez-decode-signed-bits w 16))
 
+(defun ez-decode-signed-operand (operand operand-type)
+  (if (eq operand-type 'b)
+      (ez-decode-signed-byte operand)
+    (ez-decode-signed-word operand)))
+
 (defun binformat (n &optional s)
   (unless s
     (setq s ""))
@@ -50,6 +55,14 @@
         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
@@ -59,7 +72,7 @@
 
 (defvar ez-start-pc nil)
 (defvar ez-himem-base nil)
-(defvar ez-dict-addr nil)
+(defvar ez-dict-base nil)
 (defvar ez-objtab-addr nil)
 (defvar ez-abbrevtab-addr nil)
 (defvar ez-globalvartab-addr nil)
@@ -99,10 +112,16 @@
 ;; Global variables
 
 (defun ez-get-global-var (gvar)
-  (ez-mem-ref-word (+ (* 2 gvar) ez-globalvartab-addr)))
+  (if (> gvar 239)
+      (error "Invalid global variable %d" gvar))
+  (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
 
@@ -113,46 +132,43 @@
   (dotimes (i 31)
     (aset ez-property-defaults i (aref ez-memory (+ ez-objtab-addr (* 2 i))))))
 
-(defun ez-get-obj-addr (obj-id)
-  (+ ez-objtab-addr (* 2 31) (* 9 (- obj-id 1))))
+(defun ez-get-obj-addr (obj)
+  (+ ez-objtab-addr (* 2 31) (* 9 (- obj 1))))
 
-(defun ez-get-obj-parent (obj-id)
-  (let ((addr (ez-get-obj-addr obj-id)))
+(defun ez-get-obj-parent (obj)
+  (let ((addr (ez-get-obj-addr obj)))
     (ez-mem-ref-byte (+ addr 4))))
 
-(defun ez-get-obj-sibling (obj-id)
-  (let ((addr (ez-get-obj-addr obj-id)))
+(defun ez-set-obj-parent (obj new-parent)
+  (let ((addr (ez-get-obj-addr obj)))
+    (ez-mem-set-byte (+ addr 4) new-parent)))
+
+(defun ez-get-obj-sibling (obj)
+  (let ((addr (ez-get-obj-addr obj)))
     (ez-mem-ref-byte (+ addr 5))))
 
-(defun ez-get-obj-child (obj-id)
-  (let ((addr (ez-get-obj-addr obj-id)))
+(defun ez-set-obj-sibling (obj new-sibling)
+  (let ((addr (ez-get-obj-addr obj)))
+    (ez-mem-set-byte (+ addr 5) new-sibling)))
+
+(defun ez-get-obj-child (obj)
+  (let ((addr (ez-get-obj-addr obj)))
     (ez-mem-ref-byte (+ addr 6))))
 
-(defun ez-get-obj-plist-addr (obj-id)
-  (let ((addr (ez-get-obj-addr obj-id)))
+(defun ez-set-obj-child (obj new-child)
+  (let ((addr (ez-get-obj-addr obj)))
+    (ez-mem-set-byte (+ addr 6) new-child)))
+
+(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-obj (obj-id)
-  (let ((addr (+ ez-objtab-addr
-                 (* 2 31)
-                 (* 9 (- obj-id 1)))))
-    (list
-     obj-id
-     (ez-mem-ref-byte (+ addr 4))
-     (ez-mem-ref-byte (+ addr 5))
-     (ez-mem-ref-byte (+ addr 6))
-     (ez-mem-ref-word (+ addr 7))
-     (let ((plist-addr (ez-mem-ref-word (+ addr 7))))
-       (if (> (ez-mem-ref-byte plist-addr) 0)
-           (ez-get-zstring (+ 1 plist-addr))
-         nil)))))
-
 (defun ez-get-prop-default (prop)
   (ez-mem-ref-word (+ ez-objtab-addr (* 2 (+ 1 prop)))))
 
@@ -196,6 +212,45 @@
      (t
       (ez-mem-set-word (+ prop-addr 1) value)))))
 
+(defun ez-get-obj-attr (obj attr)
+  (let* ((byte-num (/ attr 8))
+         (bit-num (mod attr 8))
+         (bit-mask (lsh 1 (- 7 bit-num))))
+    (if (> (logand bit-mask (ez-mem-ref-byte (+ (ez-get-obj-addr obj) byte-num))) 0)
+        1
+      0)))
+
+(defun ez-set-obj-attr (obj attr val)
+  (let* ((byte-num (/ attr 8))
+         (bit-num (mod attr 8))
+         (bit-mask (lsh 1 (- 7 bit-num)))
+         (byte-addr (+ (ez-get-obj-addr obj) byte-num))
+         (byte (ez-mem-ref-byte byte-addr))
+         (current-set (> (logand bit-mask byte) 0)))
+    (if (or (and current-set (= val 0))
+            (and (not current-set) (> val 0)))
+        (ez-mem-set-byte byte-addr (logxor byte bit-mask)))))
+
+
+(defun ez-remove-obj (obj)
+  (let ((parent (ez-get-obj-parent obj))
+        (sibling (ez-get-obj-sibling obj)))
+    (unless (= parent 0)
+      (let ((child (ez-get-obj-child parent)))
+        (if (= child obj)
+            (ez-set-obj-child parent sibling)
+          (while (not (= obj (ez-get-obj-sibling child)))
+            (setq child (ez-get-obj-sibling child)))
+          (ez-set-obj-sibling child (ez-get-obj-sibling obj))))
+      (ez-set-obj-parent obj 0))
+    (ez-set-obj-sibling obj 0)))
+
+(defun ez-insert-obj (obj new-parent)
+  (ez-remove-obj obj)
+  (unless (= new-parent 0)
+    (ez-set-obj-sibling obj (ez-get-obj-child new-parent))
+    (ez-set-obj-child new-parent obj)))
+
 ;; Z-strings
 
 (defvar ez-zstring-alphabets
@@ -212,31 +267,35 @@
         (logand (lsh word -5) #b11111)
         (logand word #b11111)))
 
-(defun ez-get-zstring-chars (base-addr)
+(defun ez-get-zstring-chars-and-length (base-addr)
   (let ((addr base-addr)
         (chars nil)
-        (not-done t))
+        (not-done t)
+        (word-count 0))
     (while not-done
       (let ((components (ez-parse-zstring-word (ez-mem-ref-word addr))))
         (setq chars (append chars (cdr components)))
         (setq addr (+ addr 2))
+        (setq word-count (+ word-count 1))
         (when (= (car components) 1)
           (setq not-done nil))))
-    chars))
-
-(defun ez-get-zstring (base-addr)
-  (let ((chars (ez-get-zstring-chars base-addr))
-        (cur 0)
-        (lock 0)
-        (abbrev-char nil)
-        (s ""))
+    (cons word-count chars)))
+
+(defun ez-get-zstring-and-length (base-addr)
+  (let* ((word-count-and-chars (ez-get-zstring-chars-and-length base-addr))
+         (word-count (car word-count-and-chars))
+         (chars (cdr word-count-and-chars))
+         (cur 0)
+         (lock 0)
+         (abbrev-char nil)
+         (s ""))
     (dolist (char chars)
       (cond
        (abbrev-char
         (let ((abbrev-addr
                (* 2 (ez-mem-ref-word (+ ez-abbrevtab-addr
                                         (* 2 (+ (* (- abbrev-char 1) 32) char)))))))
-          (setq s (concat s (ez-get-zstring abbrev-addr))))
+          (setq s (concat s (cdr (ez-get-zstring-and-length abbrev-addr)))))
         (setq abbrev-char nil))
        ((memq char '(1 2 3)) ;Abbreviation
         (setq abbrev-char char))
@@ -248,7 +307,10 @@
         (setq s (concat s (substring (elt ez-zstring-alphabets cur)
                                      char (+ char 1))))
         (setq cur lock))))
-    s))
+    (cons word-count s)))
+
+(defun ez-get-zstring (base-addr)
+  (cdr (ez-get-zstring-and-length base-addr)))
 
 
 ;; Call stack
@@ -272,20 +334,25 @@
 
 (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 ()
@@ -333,9 +400,7 @@
 (defun ez-execute-instr ()
   (let ((instr-pc (ez-get-pc))
         (opbyte (ez-read-pc-byte-and-inc))
-        (optype)
-        (opcode nil)
-        (operands))
+        (optype) (opcode) (operands))
     (cond
      ((<= #x0 opbyte #x1f)
       (setq optype '2op
@@ -378,9 +443,15 @@
             operand-types '(w)))
      ((<= #xB0 opbyte #xBF)
       (setq optype '0op
-            opcode (- opbyte #xb0)))
+            opcode (- opbyte #xb0)
+            operands '()
+            operand-types '()))
      ((<= #xC0 opbyte #xDF)
-      (error "Unsupported op %x" opbyte))
+      (setq optype '2op
+            opcode (- opbyte #xc0))
+      (let ((operands-and-types (ez-read-var-operands-and-inc)))
+        (setq operands (car operands-and-types)
+              operand-types (cdr operands-and-types))))
      ((<= #xE0 opbyte #xFF)
       (setq optype 'var
             opcode (- opbyte #xe0))
@@ -390,10 +461,11 @@
     (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"
-                 instr-pc optype opcode mnemonic operands))
+        (message "PC:%x Optype:%s Opcode:%x Mnemonic:%s Operands:%s Operand-types:%s"
+                 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 ()
@@ -402,19 +474,18 @@
                   (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)))))))))))))
-         (operands nil))
+                                                  (list type4))))))))))))))
     (cons
      (mapcar
       (lambda (type)
@@ -461,13 +532,24 @@
   '(((0op #x00) rtrue ez-op-rtrue)
     ((0op #x01) rfalse ez-op-rfalse)
     ((1op #x00) jz ez-op-jz)
+    ((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)
     ((2op #x0D) store ez-op-store)
     ((1op #x0E) load ez-op-load)
     ((var #x01) storew ez-op-storew)
     ((2op #x0F) loadw ez-op-loadw)
+    ((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)
@@ -475,19 +557,36 @@
     ((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)
     ((2op #x0A) test_attr ez-op-test-attr)
-    ((var #x03) put_prop ez-op-put-prop)))
+    ((2op #x0B) set_attr ez-op-set-attr)
+    ((2op #x0C) clear_attr ez-op-clear-attr)
+    ((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)
+    ((1op #x0A) print_obj ez-op-print-obj)))
 
 (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)
 
+(defun ez-op-ret-pulled (operands operand-types)
+  (let ((retval (ez-routine-stack-pop)))
+    (message "\tReturning value %x" retval)
+    (ez-op-ret (list retval)))
+  t)
+
 (defun ez-op-rtrue (&optional operands operand-types)
   (ez-op-ret (list 1))
   t)
@@ -504,6 +603,43 @@
   (ez-do-branch (memq (car operands) (cdr operands)))
   t)
 
+(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)
+
+(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)
+
+(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)
+
+(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)
+
+(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)))))
+  t)
+
+(defun ez-op-test (operands operand-types)
+  (let ((a (car operands))
+        (b (cadr operands)))
+    (ez-do-branch (= (logand a b) b)))
+  t)
+
 (defun ez-op-jump (operands operand-types)
   (let ((offset (if (eq (car operand-types) 'b)
                     (ez-decode-signed-byte (car operands))
@@ -511,6 +647,16 @@
     (ez-set-pc (+ (ez-get-pc) offset -2)))
   t)
 
+(defun ez-op-inc (operands &optional operand-types)
+  (let ((var (car operands)))
+    (ez-set-var var (mod (+ 1 (ez-get-var var)) #x10000)))
+  t)
+
+(defun ez-op-dec (operands &optional operand-types)
+  (let ((var (car operands)))
+    (ez-set-var var (mod (+ (ez-get-var var) 1) #x10000)))
+  t)
+
 (defun ez-op-store (operands operand-types)
   (let ((var (car operands))
         (a (cadr operands)))
@@ -535,6 +681,19 @@
     (ez-set-var (ez-read-pc-byte-and-inc) (ez-mem-ref-word (+ baddr (* 2 n)))))
   t)
 
+(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)
+
+(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)
+
 (defun ez-op-and (operands operand-types)
   (let ((a (car operands))
         (b (cadr operands)))
@@ -571,18 +730,20 @@
 (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)))))))
+    (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))))))))
   t)
 
 (defun ez-op-test-attr (operands operand-types)
@@ -591,32 +752,88 @@
     (ez-do-branch (= 1 (ez-get-obj-attr obj attr)))
     t))
 
+(defun ez-op-set-attr (operands operand-types)
+  (let ((obj (car operands))
+        (attr (cadr operands)))
+    (ez-set-obj-attr obj attr 1))
+  t)
+
+(defun ez-op-clear-attr (operands operand-types)
+  (let ((obj (car operands))
+        (attr (cadr operands)))
+    (ez-set-obj-attr obj attr 0))
+  t)
+
 (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)))
+  t)
 
 (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)))
+  t)
 
 (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))
+  t)
+
+(defun ez-op-remove-obj (operands operand-types)
+  (let ((obj (car operands)))
+    (ez-remove-obj obj))
+  t)
+
+(defun ez-op-insert-obj (operands operand-types)
+  (let ((obj1 (car operands))
+        (obj2 (cadr operands)))
+    (ez-insert-obj obj1 obj2))
+  t)
 
 (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))
+  t)
 
-;; Main
+(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)))
+  t)
+
+(defun ez-op-print (operands operand-types)
+  (let* ((word-count-and-string (ez-get-zstring-and-length (ez-get-pc)))
+         (word-count (car word-count-and-string))
+         (string (cdr word-count-and-string)))
+    (ez-print string)
+    (ez-increment-pc (* 2 word-count)))
+  t)
+
+(defun ez-op-new-line (operands operand-types)
+  (ez-print "\n")
+  t)
+
+(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)
+
+(defun ez-op-print-char (operands operand-types)
+  (let ((c (car operands)))
+    (ez-print (string c)))
+  t)
+
+(defun ez-op-print-obj (operands operand-types)
+  (let ((obj (car operands)))
+    (ez-print (ez-get-obj-name obj)))
+  t)
+
+;; Execution loop
 
 (defun ez-run (filename)
   (ez-load-file filename)
@@ -625,13 +842,58 @@
 
   (while (ez-execute-instr)))
 
-;; Scratch
-
-;; (ez-load-file "zork1.z3")
-;; (ez-parse-header)
-;; (setq ez-call-stack (list (ez-make-call-stack-frame ez-start-pc)))
-;; (while (ez-execute-instr))
 
-(ez-run "zork1.z3")
+;;; Buffer and I/O
+;;
+
+(defvar ez-input-marker nil
+  "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-input-marker)
+        (set-marker ez-input-marker (point-max))
+      (setq ez-input-marker (point-max-marker)))
+    (goto-char (point-max))))
+
+
+(defun ez-print (string)
+  (with-current-buffer "*ez*"
+    (save-excursion
+      (goto-char ez-input-marker)
+      (insert-before-markers string))))
+
+;; Mode
+
+(defvar ez-mode-map
+  (let ((map (make-sparse-keymap)))
+    (define-key map (kbd "RET") 'ez-enter)
+    map))
+
+(define-derived-mode ez-mode text-mode "ez"
+  "Major mode for EZ.")
+
+(when (fboundp 'evil-set-initial-state)
+  (evil-set-initial-state 'ez-mode 'insert))
+
+(defun ez (zfile)
+  (interactive "fEnter name of z3 story file: ")
+  (if (get-buffer "*ez*")
+      (switch-to-buffer "*ez*")
+    (switch-to-buffer "*ez*")
+    (ez-mode)
+    (ez-setup-buffer)
+    (ez-run zfile))
+  "Started EZ.")
+
+(defun ez-debug ()
+  (interactive)
+  (switch-to-buffer "*ez*")
+  (ez-mode)
+  (ez-setup-buffer)
+  (ez-run "zork1.z3"))
 
 ;;; ez.el ends here