Added missing edge case to call_fv implementation.

[ez.git] / ez.el

diff --git a/ez.el b/ez.el
index 3948f4c..9dcfdee 100644 (file)
--- a/ez.el
+++ b/ez.el
@@ -114,10 +114,14 @@
 (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
 
@@ -330,20 +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 ()
@@ -379,13 +388,10 @@
 (defun ez-set-var (var val)
   (cond
    ((= var 0)
-    (message "Pushed %x to stack" val)
     (ez-routine-stack-push val))
    ((< var 16)
-    (message "Saved %x to local variable %x" val var)
     (ez-set-local-var var val))
    (t
-    (message "Saved %x to global variable %x" val (- var 16))
     (ez-set-global-var (- var 16) val))))
 
 (defun ez-read-pc-var-and-inc ()
@@ -548,7 +554,7 @@
     ((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)
@@ -567,6 +573,7 @@
 
 (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)
@@ -708,18 +715,20 @@
 (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)