# HG changeset patch
# User Robert McIntyre <rlm@mit.edu>
# Date 1340246498 18000
# Node ID e6c02264dc9c119e6b3df047204f6b35ee27790b
# Parent  24b459a95b464a0124c4efd747cbb0bb0f930b7b
trying to track down pesky assembly bug.

diff -r 24b459a95b46 -r e6c02264dc9c clojure/com/aurellem/run/image.clj
--- a/clojure/com/aurellem/run/image.clj	Wed Jun 20 19:51:50 2012 -0500
+++ b/clojure/com/aurellem/run/image.clj	Wed Jun 20 21:41:38 2012 -0500
@@ -427,9 +427,78 @@
       (map row->bits
            (partition 8 tile))))))
 
-  
 
-(defn display-image-kernel [^BufferedImage image]
+(defn write-data
+  "Efficient assembly to write a sequence of values to
+   memory, starting at a target address."
+  [base-address target-address data]
+  (let [len (count data)]
+    (flatten
+     (if (<= len 255)
+       [0x21 ;; load data address start into HL
+        (reverse (disect-bytes-2 (+ 16 base-address)))
+
+        0x01 ;; load target address into BC
+        (reverse (disect-bytes-2 target-address))
+        
+        0x16 ;; load len into D
+        len
+
+        
+        ;; data x-fer loop start
+        0x2A ;; (HL) -> A; HL++;
+        0x02 ;; A -> (BC);
+        0x03 ;; INC BC;
+        0x15 ;; DEC D
+
+        0x20 ;; if D is not now 0,
+        (->signed-8-bit -6) ;; GOTO start
+        
+        0x18
+        len
+        
+        data]
+       (let [first-part (write-data base-address target-address
+                                    (take 255 data))]
+         [first-part 
+          (write-data (+ base-address (count first-part))
+                      (+ target-address 255)
+                      (drop 255 data))])))))
+
+(defn test-write-data []
+  (let [test-data (repeat 3 0xD3)
+        base-address 0xA000
+        target-address 0xA500
+
+        test-kernel
+        (flatten
+         [0xF3 ;; disable interrupts
+          (write-data (+ 1 base-address)
+                      target-address test-data)
+          (infinite-loop)])]
+;;    (assert
+  ;;   (= test-data
+    (-> (mid-game)
+        tick tick tick
+        (set-memory-range base-address test-kernel)
+        (PC! base-address)
+
+        ;;(run-moves (repeat 100 []))
+        ;;(memory)
+        ;;vec
+        ;;(subvec target-address
+        ;;        (+ target-address
+        ;;           (count test-data)))
+        ;;println
+        )))
+
+    
+        
+    
+
+
+
+(defn display-image-kernel [base-address ^BufferedImage image]
   (let [gb-image (image->gb-image image)]
   
     [(clear-music-registers)
@@ -455,17 +524,16 @@
      ;; section
      
 
-
      ;; [ ] disable the display of OBJ tiles.
      
 
      ;; [ ] reactivate the LCD display
      
 
-     (infinite-loop)
+     (infinite-loop)]
 
      
-  )
+  ))