diff --git a/assembler.c b/assembler.c
index ef9edff..8b15988 100644
--- a/assembler.c
+++ b/assembler.c
@@ -48,7 +48,7 @@ char ops[][4] = {
 	"BRK", "NOP", "LIT", "LDR", "STR", "---", "JMP", "JSR", 
 	"EQU", "NEQ", "GTH", "LTH", "AND", "ORA", "EOR", "SFT",
 	"POP", "DUP", "SWP", "OVR", "ROT", "---", "CLN", "STH",
-	"ADD", "SUB", "MUL", "DIV", "---", "---", "---", "---"
+	"ADD", "SUB", "MUL", "DIV", "---", "---", "GTS", "LTS"
 };
 
 int   scin(char *s, char c) { int i = 0; while(s[i]) if(s[i++] == c) return i - 1; return -1; } /* string char index */
diff --git a/build.sh b/build.sh
index 539d023..b976d44 100755
--- a/build.sh
+++ b/build.sh
@@ -20,5 +20,5 @@ cc -std=c89 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werr
 # cc uxn.c emulator.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -L/usr/local/lib -lSDL2 -o bin/emulator
 
 # run
-./bin/assembler projects/software/nasu.usm bin/boot.rom
+./bin/assembler projects/examples/gui.shapes.usm bin/boot.rom
 ./bin/emulator bin/boot.rom
diff --git a/projects/examples/gui.shapes.usm b/projects/examples/gui.shapes.usm
index 53bd657..f270b99 100644
--- a/projects/examples/gui.shapes.usm
+++ b/projects/examples/gui.shapes.usm
@@ -3,11 +3,19 @@
 %RTN { JMP2r }
 %++  { #0001 ADD2 }
 %8+  { #0008 ADD2 }
+%ABS2 { DUP2 #000f SFT2 #ffff SWP2 SWP POP MUL2? } 
 
 ;label { x 2 y 2 color 1 addr 2 }
 ;pict { x 2 y 2 width 2 height 2 color 1 addr 2 }
 ;rect { x1 2 y1 2 x2 2 y2 2 }
 ;color { byte 1 }
+( clean up )
+;a { x 2 y 2 }
+;b { x 2 y 2 }
+;s { x 2 y 2 }
+;d { x 2 y 2 }
+;err { short 2 }
+;err2 { short 2 }
 
 |0100 @RESET
 	
@@ -27,6 +35,11 @@
 	#0038 #0078 #02 ,text ,draw-label JSR2
 	#0048 #0088 #03 ,text ,draw-label JSR2
 	#0058 #0098 #04 ,text ,draw-label JSR2
+
+	#0020 #0020 #0070 #0080 #01 ,draw-line JSR2
+	#0020 #0080 #0070 #0030 #02 ,draw-line JSR2
+	#00a0 #0020 #0050 #00b0 #03 ,draw-line JSR2
+	#00b0 #0090 #0030 #0010 #01 ,draw-line JSR2
 	
 BRK
 
@@ -88,6 +101,38 @@ RTN
 
 RTN
 
+@draw-line ( x1 y1 x2 y2 )
+	
+	=color
+	=b.y =b.x =a.y =a.x
+	~b.x ~a.x SUB2 ABS2 =d.x
+	~b.y ~a.y SUB2 ABS2 #0000 SWP2 SUB2 =d.y
+	#ffff #00 ~a.x ~b.x LTS2 #0002 MUL2 ADD2 =s.x 
+	#ffff #00 ~a.y ~b.y LTS2 #0002 MUL2 ADD2 =s.y 
+	~d.x ~d.y ADD2 =err
+
+	$loop
+
+		~a.x =Screen.x ~a.y =Screen.y ~color =Screen.color
+		,$end ~a.x ~b.x EQU2 ~a.y ~b.y EQU2 #0101 EQU2 JMP2?
+		~err #0002 MUL2 =err2
+
+		,$skipy ~err2 ~d.y LTS2 JMP2?
+			~err ~d.y ADD2 =err
+			~a.x ~s.x ADD2 =a.x
+		$skipy
+
+		,$skipx ~err2 ~d.x GTS2 JMP2?
+			~err ~d.x ADD2 =err
+			~a.y ~s.y ADD2 =a.y
+		$skipx
+
+		,$loop JMP2
+
+	$end
+
+RTN
+
 @pict_small [
 
 	ff80 8080 8080 8088 ffff fffc f8f9 f1f4
@@ -145,4 +190,4 @@ RTN
 |FF20 ;Sprite { pad 8 x 2 y 2 addr 2 color 1 }
 
 |FFF0 .RESET .FRAME .ERROR ( vectors )
-|FFF8 [ 0f0f 0fff 0ff0 ] ( palette )
\ No newline at end of file
+|FFF8 [ 13fd 1ef3 1bf2 ] ( palette )
\ No newline at end of file
diff --git a/projects/tests/draw.usm b/projects/tests/draw.usm
index 261d134..9c4ecf3 100644
--- a/projects/tests/draw.usm
+++ b/projects/tests/draw.usm
@@ -2,74 +2,51 @@
 
 %RTN   { JMP2r }
 %RTN?  { JMP2r? }
+%ABS { DUP #07 SHR #ff SWP MUL? }
+%ABS2 { DUP2 #000f SFT2 #ffff SWP2 SWP POP MUL2? } 
 
 ;cursor { x 2 y 2 }
 ;a { x 2 y 2 }
 ;b { x 2 y 2 }
 ;s { x 2 y 2 }
+;d { x 2 y 2 }
+;err { short 2 }
+;err2 { short 2 }
+;i { byte 1 }
+;color { byte 1 }
 
 |0100 @RESET 
 	
-	#0020 #0020 #0070 #0080 ,draw-line JSR2
-	#0020 #0080 #0070 #0030 ,draw-line JSR2
-	#00a0 #0020 #0050 #00b0 ,draw-line JSR2
-	#00b0 #0090 #0030 #0010 ,draw-line JSR2
+	#0020 #0020 #0070 #0080 #01 ,draw-line JSR2
+	#0020 #0080 #0070 #0030 #02 ,draw-line JSR2
+	#00a0 #0020 #0050 #00b0 #03 ,draw-line JSR2
+	#00b0 #0090 #0030 #0010 #01 ,draw-line JSR2
 
 BRK
 
 @draw-line ( x1 y1 x2 y2 )
-
-	=b.y =b.x ( target, b )
-	=a.y =a.x ( target, a )
-
-	~a.x =Screen.x ~a.y =Screen.y #02 =Screen.color
-	~b.x =Screen.x ~b.y =Screen.y #02 =Screen.color
-
-	( dx = abs[bx - ax] )
+	
+	=color
+	=b.y =b.x =a.y =a.x
 	~b.x ~a.x SUB2 ABS2 =d.x
-
-	( dy = -abs[by - ay] )
 	~b.y ~a.y SUB2 ABS2 #0000 SWP2 SUB2 =d.y
-
-	( sx = ax < bx ? 1 : -1; )
-	#ffff #00 ~a.x ~b.x LTH2 #0002 MUL2 ADD2 =s.x 
-
-	( sy = ay < by ? 1 : -1; )
-	#ffff #00 ~a.y ~b.y LTH2 #0002 MUL2 ADD2 =s.y 
-
-	( err = dx + dy )
+	#ffff #00 ~a.x ~b.x LTS2 #0002 MUL2 ADD2 =s.x 
+	#ffff #00 ~a.y ~b.y LTS2 #0002 MUL2 ADD2 =s.y 
 	~d.x ~d.y ADD2 =err
 
-	( loop )
 	$loop
 
-		( putchr[ax, ay, color]; )
-		~a.x =Screen.x ~a.y =Screen.y #01 =Screen.color
-
-		( if[ax == bx && ay == by] break; )
+		~a.x =Screen.x ~a.y =Screen.y ~color =Screen.color
 		,$end ~a.x ~b.x EQU2 ~a.y ~b.y EQU2 #0101 EQU2 JMP2?
-
-		( fallback, remove )
-		,$end ~i #90 GTH JMP2? ~i #01 ADD =i
-
-		( err2 = 2 * err; )
 		~err #0002 MUL2 =err2
 
-		~err2 =Console.short
-
-		( if[err2 >= dy] )
-		,$skipy ~err2 ~d.y LTH2 JMP2?
-			( err += dy; )
+		,$skipy ~err2 ~d.y LTS2 JMP2?
 			~err ~d.y ADD2 =err
-			( ax += sx; )
 			~a.x ~s.x ADD2 =a.x
 		$skipy
 
-		( if[err2 <= dx] )
-		,$skipx ~err2 ~d.x GTH2 JMP2?
-			( err += dx; )
+		,$skipx ~err2 ~d.x GTS2 JMP2?
 			~err ~d.x ADD2 =err
-			( ay += sy; )
 			~a.y ~s.y ADD2 =a.y
 		$skipx
 
@@ -83,6 +60,12 @@ RTN
 |d000 @ERROR 
 
 |FF00 ;Console { pad 8 char 1 byte 1 short 2 }
+|FF10 ;Screen { width 2 height 2 pad 4 x 2 y 2 color 1 }
+|FF20 ;Sprite { pad 8 x 2 y 2 addr 2 color 1 }
+|FF30 ;Controller { buttons 1 }
+|FF40 ;Keys { key 1 }
+|FF50 ;Mouse { x 2 y 2 state 1 chord 1 change 1 }
+|FF60 ;File { pad 8 name 2 length 2 load 2 save 2 }
 
 |FFF0 .RESET .FRAME .ERROR ( vectors )
 |FFF8 [ 13fd 1ef3 1bf2 ] ( palette )
\ No newline at end of file
diff --git a/uxn.c b/uxn.c
index 3cf16e1..a848c30 100644
--- a/uxn.c
+++ b/uxn.c
@@ -58,7 +58,9 @@ void op_div(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b
 void op_equ(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b == a); }
 void op_neq(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b != a); }
 void op_gth(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b > a); }
+void op_gts(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, (Sint8)b > (Sint8)a); }
 void op_lth(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, b < a); }
+void op_lts(Uxn *u) { Uint8 a = pop8(u->src), b = pop8(u->src); push8(u->src, (Sint8)b < (Sint8)a); }
 /* --- */
 void op_lit16(Uxn *u) { u->literal += 2; }
 void op_nop16(Uxn *u) { printf("%04x\n", pop16(u->src)); }
@@ -87,18 +89,20 @@ void op_div16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push16(u->s
 void op_equ16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, b == a); }
 void op_neq16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, b != a); }
 void op_gth16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, b > a); }
+void op_gts16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, (Sint16)b > (Sint16)a); }
 void op_lth16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, b < a); }
+void op_lts16(Uxn *u) { Uint16 a = pop16(u->src), b = pop16(u->src); push8(u->src, (Sint16)b < (Sint16)a); }
 
 void (*ops[])(Uxn *u) = {
 	op_brk, op_nop, op_lit, op_ldr, op_str, op_nop, op_jmp, op_jsr, 
 	op_equ, op_neq, op_gth, op_lth, op_and, op_ora, op_eor, op_sft, 
 	op_pop, op_dup, op_swp, op_ovr, op_rot, op_nop, op_cln, op_sth, 
-	op_add, op_sub, op_mul, op_div, op_nop, op_nop, op_nop, op_eor,
+	op_add, op_sub, op_mul, op_div, op_nop, op_nop, op_gts, op_lts,
 	/* 16-bit */
 	op_brk,   op_nop16, op_lit16, op_ldr16, op_str16, op_nop,   op_jmp16, op_jsr16, 
 	op_equ16, op_neq16, op_gth16, op_lth16, op_and16, op_ora16, op_eor16, op_sft16, 
 	op_pop16, op_dup16, op_swp16, op_ovr16, op_rot16, op_nop,   op_cln16, op_sth16, 
-	op_add16, op_sub16, op_mul16, op_div16, op_nop,   op_nop,   op_nop,   op_nop
+	op_add16, op_sub16, op_mul16, op_div16, op_nop,   op_nop,   op_gts16,   op_lts16
 };
 
 Uint8 opr[][4] = { /* wstack-/+ rstack-/+ */