(hilbert) Faster drawing routine

projects/examples/demos/hilbert.tal

@@ -5,9 +5,9 @@
 
 @on-reset ( -> )
 	( | theme )
-	#6f0b .System/r DEO2
-	#7f0a .System/g DEO2
-	#8e0a .System/b DEO2
+	#6fff .System/r DEO2
+	#7fff .System/g DEO2
+	#8fff .System/b DEO2
 	( | screen size )
 	#00c0
 	( ) DUP2 .Screen/width DEO2
@@ -24,10 +24,24 @@
 	[ LIT2 &x1 0020 ] [ LIT2 &y1 0020 ]
 	( ) [ LIT2 &f $2 ] INC2 DUP2 ,&f STR2
 	d2xy
-	( ) DUP2 ,&y1 STR2
-	( ) OVR2 ,&x1 STR2
-	#01 <draw-line>
-	BRK
+	( cache y ) DUP2 ,&y1 STR2
+	( cache x ) OVR2 ,&x1 STR2
+	( | draw line )
+	ROT2 SWP2 diff ,&y STR2
+	diff ,&x STR2
+	#0400
+	&l ( -- )
+		.Screen/x DEI2k [ LIT2 &x $2 ] ADD2 ROT DEO2
+		.Screen/y DEI2k [ LIT2 &y $2 ] ADD2 ROT DEO2
+		[ LIT2 01 -Screen/pixel ] DEO
+		INC GTHk ?&l
+	POP2 BRK
+
+@diff ( a* b* -- dir* )
+	EQU2k ?{
+		GTH2 ?{ #0001 JMP2r }
+		#ffff JMP2r }
+	POP2 POP2 #0000 JMP2r
 
 @d2xy ( d* -- x* y* )
 	,&t STR2
@@ -60,39 +74,3 @@
 		( swap ) SWP2 }
 	POP2r JMP2r
 
-@<draw-line> ( x1* y1* x2* y2* color -- )
-	,&color STR
-	,&y STR2
-	,&x STR2
-	,&y2 STR2
-	,&x2 STR2
-	,&x LDR2 ,&x2 LDR2 SUB2 abs2 ,&dx STR2
-	#0000 ,&y LDR2 ,&y2 LDR2 SUB2 abs2 SUB2 ,&dy STR2
-	#ffff [ LIT2 00 _&x2 ] LDR2 ,&x LDR2 lts2 DUP2 ADD2 ADD2 ,&sx STR2
-	#ffff [ LIT2 00 _&y2 ] LDR2 ,&y LDR2 lts2 DUP2 ADD2 ADD2 ,&sy STR2
-	[ LIT2 &dx $2 ] [ LIT2 &dy $2 ] ADD2 STH2
-	&while ( -- )
-		[ LIT2 &x2 $2 ] DUP2 .Screen/x DEO2
-		[ LIT2 &x $2 ] EQU2 [ LIT2 &y2 $2 ] DUP2 .Screen/y DEO2
-		[ LIT2 &y $2 ] EQU2 [ LIT2 &color $1 -Screen/pixel ] DEO
-		AND ?&end
-		STH2kr DUP2 ADD2 DUP2 ,&dy LDR2 lts2 ?&skipy
-		STH2r ,&dy LDR2 ADD2 STH2
-		,&x2 LDR2 [ LIT2 &sx $2 ] ADD2 ,&x2 STR2
-	&skipy ( -- )
-		,&dx LDR2 gts2 ?&while
-	STH2r ,&dx LDR2 ADD2 STH2
-	,&y2 LDR2 [ LIT2 &sy $2 ] ADD2 ,&y2 STR2
-	!&while
-	&end POP2r JMP2r
-
-@abs2 ( a* -- f )
-	DUP2 #0f SFT2 EQU ?{ #0000 SWP2 SUB2 }
-	JMP2r
-
-@lts2 ( a* b* -- f )
-	#8000 STH2k ADD2 SWP2 STH2r ADD2 GTH2 JMP2r
-
-@gts2 ( a* b* -- f )
-	#8000 STH2k ADD2 SWP2 STH2r ADD2 LTH2 JMP2r
-