# HG changeset patch
# User Robert McIntyre <rlm@mit.edu>
# Date 1346489790 18000
# Node ID 40f62391db9df25e25164d73dfd9941bcc3a1164
# Parent  58a25fa1517604937bbb868e2bd6776fc73c5daf
implemented row and column increment logic.

diff -r 58a25fa15176 -r 40f62391db9d clojure/com/aurellem/run/adv_choreo.clj
--- a/clojure/com/aurellem/run/adv_choreo.clj	Sat Sep 01 03:42:16 2012 -0500
+++ b/clojure/com/aurellem/run/adv_choreo.clj	Sat Sep 01 03:56:30 2012 -0500
@@ -232,9 +232,42 @@
                 ;; restore all registers
                 0xF1 0xE1 0xD1 0xC1])
 
+              increment-row-column
+              [;; D contains row and E contains column
+               
+               ;; every time column (E) reaches 20, set
+               ;; column to 0 and increment row
+               0x1C ;; inc E
+               0x3E 20 0xBB ;; compare E to 20
+               0x20 ;; if E is 20
+                 3
+                 0x1E 0 ;; set E to zero
+                 0x14   ;; (inc D) -> D
+
+               ;; every time row (D) reaches 18, set row to 0                
+               0x3E 18 0xBA ;; compare D to 18
+               0x20 ;; if D is 18
+                 2
+                 0x16 0] ;; set D to zero
+               
+              set-HL-from-row-and-column
+              [;; formula for memory offset is:
+               ;; (+ 0x9800 (* 32 row) column)
+               0xD5
+
+               0xD1
+
+               ]
+              
+
+              
+              
               render-glyph
               (flatten
-               [0 0 
+               [set-HL-from-row-and-column
+                increment-row-column
+                ;; Render each nybble of A as a character
+                ;; there are two characters to a glyph.
                 ])
 
               
@@ -252,10 +285,10 @@
           ;; Reset HL to initial value
           0x21
           (reverse (disect-bytes-2 data-start))
-          0x78 0x22 ;; BC -> save glyphs-rendered
+          0x78 0x22 ;; BC ->  glyphs-rendered to RAM
           0x79 0x22 ;;
 
-          0x7A 0x22 ;; D -> rows 
+          0x7A 0x22 ;; D -> rows       -> to RAM
           0x7B 0x22 ;; E -> columns
           ])