Initial commit

diff --git a/main.asm b/main.asm
index b4444ac9a18815bf5d8dae40f7d71dd7caa66229..bb6637d4958bb5f852b000c6863a1e12cd8f78ec 100644 (file)
--- a/main.asm
+++ b/main.asm
@@ -284,6 +284,32 @@ TurtleSprite
        .byte  %11100000
 
        ;------------------------------------------------------------------------------
+
+       ;-----------------------------
+       ; This table converts the "remainder" of the division by 15 (-1 to -15) to the correct
+       ; fine adjustment value. This table is on a page boundary to guarantee the processor
+       ; will cross a page boundary and waste a cycle in order to be at the precise position
+       ; for a RESP0,x write
+
+fineAdjustBegin
+       .byte %01110000; Left 7
+       .byte %01100000; Left 6
+       .byte %01010000; Left 5
+       .byte %01000000; Left 4
+       .byte %00110000; Left 3
+       .byte %00100000; Left 2
+       .byte %00010000; Left 1
+       .byte %00000000; No movement.
+       .byte %11110000; Right 1
+       .byte %11100000; Right 2
+       .byte %11010000; Right 3
+       .byte %11000000; Right 4
+       .byte %10110000; Right 5
+       .byte %10100000; Right 6
+       .byte %10010000; Right 7
+
+fineAdjustTable EQU fineAdjustBegin - %11110001; NOTE: %11110001 = -15
+
        ORG $FFFA
 
 InterruptVectors