draw nibbles with offsets instead of conditionals

projects/nibble-dice-tracker.tal

@@ -400,7 +400,7 @@ RTN
     &normal-mode
 			#00 ( mode )
     &draw
-		;draw-byte JSR2
+		,draw-byte JSR
 		#0010 ADD2 ( increment y )
 		STHr ( recover counter )
 	#01 ADD DUP column-size ,&offset LDR ADD NEQ ,&loop JCN
@@ -422,17 +422,18 @@ RTN
   STHr DUP STH ( restore, duplicate, stash byte )
   #04 SFT #0f AND (  get high nibble )
   ,&high-nibble-mode LDR
-  ;draw-nibble JSR2 ( draw high nibble )
+  ,draw-nibble JSR ( draw high nibble )
 
 	SWP2 #0010 ADD2 SWP2 ( increment x )
 
   STHr ( restore byte )
   #0f AND ( get low nibble )
   ,&low-nibble-mode LDR
-  ;draw-nibble JSR2 ( draw low nibble )
+  ,draw-nibble JSR ( draw low nibble )
 
 RTN
 
+
 @draw-nibble ( x2 y2 num mode  -- )
   ,&set-invert JCN  ( check mode: 0 is normal, nonzero is inverted )
   &set-normal
@@ -448,50 +449,39 @@ RTN
 	.Screen/y DEO2
   .Screen/x DEO2
   STHkr
-	#03 SFT #01 AND ,&bit-3-on JCN
-  &bit-3-off
-    ;nibble-dice-empty/tl .Screen/addr DEO2
-	  ,&bit-3-draw JMP
-  &bit-3-on
-    ;nibble-dice-dot/tl .Screen/addr DEO2
-  &bit-3-draw
-    .die-color LDZ .Screen/color DEO 
+	#03 SFT ( get bit )
+	;nibble-dice-empty/tl
+	,draw-bit JSR
  
   ( bit 2 )
 	STHkr
   .Screen/x DEI2 #0008 ADD2 .Screen/x DEO2 ( increment x )
-	#02 SFT #01 AND ,&bit-2-on JCN
-  &bit-2-off
-    ;nibble-dice-empty/tr .Screen/addr DEO2
-	  ,&bit-2-draw JMP
-  &bit-2-on
-    ;nibble-dice-dot/tr .Screen/addr DEO2
-  &bit-2-draw
-    .die-color LDZ .Screen/color DEO 
+	#02 SFT ( get bit )
+	;nibble-dice-empty/tr
+	,draw-bit JSR
 
   ( bit 0 )
 	STHkr
   .Screen/y DEI2 #0008 ADD2 .Screen/y DEO2 ( increment y )
-	#01 AND ,&bit-0-on JCN
-  &bit-0-off
-    ;nibble-dice-empty/br .Screen/addr DEO2
-	  ,&bit-0-draw JMP
-  &bit-0-on
-    ;nibble-dice-dot/br .Screen/addr DEO2
-  &bit-0-draw
-    .die-color LDZ .Screen/color DEO 
+	;nibble-dice-empty/br
+	,draw-bit JSR
 
   ( bit 1 )
 	STHr 
   .Screen/x DEI2 #0008 SUB2 .Screen/x DEO2 ( decrement x )
-	#01 SFT #01 AND ,&bit-1-on JCN
-  &bit-1-off
-    ;nibble-dice-empty/bl .Screen/addr DEO2
-	  ,&bit-1-draw JMP
-  &bit-1-on
-    ;nibble-dice-dot/bl .Screen/addr DEO2
-  &bit-1-draw
-    .die-color LDZ .Screen/color DEO 
+	#01 SFT ( get bit )
+	;nibble-dice-empty/bl
+	,draw-bit JSR
+RTN
+
+@draw-bit ( number empty-tile-addr  -- )
+	STH2 ( stash address )
+	#01 AND ( get lsb from number )
+	#40 MUL #00 SWP ( convert to offset )
+	STH2r ( retrieve address )
+	ADD2 ( add offset to address  )
+	.Screen/addr DEO2
+	.die-color LDZ .Screen/color DEO 
 RTN
 
 ( sprites )
@@ -511,7 +501,6 @@ ffff ffff ffff ffff
 &br fe fe fe fe fe fc f8 00  fe ce 86 86 ce fc f8 00
 
 
-
 ( samples )
 
 ( from the audio.channels.tal uxn example )