diff --git a/README.md b/README.md
index 38fef20..5764636 100644
--- a/README.md
+++ b/README.md
@@ -34,6 +34,8 @@ evaluxn(u, u->vframe); /* Each frame
 
 - `,literal`, push label value to stack, prefixed with `LIT LEN`.
 - `.pointer`, push label value to stack.
+- `+1234`, push positive lit signed value to stack.
+- `-abcd`, push negative lit signed value to stack.
 
 ### Special
 
@@ -82,14 +84,12 @@ BRK
 
 ## TODOs
 
-- Implement signed flag to operators.
+- Line routine
 - On-screen debugger.
 - Auto-advance ldr?
 - Getting rid of IOR/IOW would be nice..
 - Sending from the wst to the rst, balance mode/flag?
 - Device that works like an extra memory bank
-- Line routine
-- LineRect routine
 - Draw a chr sprite.
 
 ## Refs
diff --git a/assembler.c b/assembler.c
index 4f02b7e..7bf7928 100644
--- a/assembler.c
+++ b/assembler.c
@@ -12,7 +12,9 @@ WITH REGARD TO THIS SOFTWARE.
 */
 
 typedef unsigned char Uint8;
+typedef signed char Sint8;
 typedef unsigned short Uint16;
+typedef signed short Sint16;
 
 typedef struct {
 	int ptr;
@@ -61,6 +63,7 @@ pushbyte(Uint8 b, int lit)
 void
 pushshort(Uint16 s, int lit)
 {
+	printf("%04x[%d]\n", s, lit);
 	if(lit) {
 		pushbyte(0x03, 0);
 		pushbyte(0x02, 0);
@@ -100,7 +103,7 @@ findoperator(char *s)
 			continue;
 		while(s[3 + m]) {
 			if(s[3 + m] == '^') i |= (1 << 5); /* mode: 16 bits */
-			if(s[3 + m] == '~') i |= (1 << 6); /* mode: signed */
+			if(s[3 + m] == '!') i |= (1 << 6); /* mode: signed */
 			if(s[3 + m] == '?') i |= (1 << 7); /* mode: conditional */
 			m++;
 		}
@@ -124,6 +127,8 @@ makelabel(char *name, Uint16 addr)
 	Label *l;
 	if(findlabel(name))
 		return error("Label duplicate", name);
+	if(sihx(name))
+		return error("Label name is hex number", name);
 	l = &labels[labelslen++];
 	l->addr = addr;
 	scpy(name, l->name, 64);
@@ -176,6 +181,8 @@ pass1(FILE *f)
 			case '"': addr += slen(w + 1) + 2; break;
 			case '#': addr += 4; break;
 			case '.': addr += 2; break;
+			case '+': /* signed positive */
+			case '-': /* signed negative */
 			case ',':
 				addr += (sihx(w + 1) && slen(w + 1) == 2 ? 1 : 2);
 				addr += (sihx(w + 1) ? slen(w + 1) / 2 : 2);
@@ -198,26 +205,22 @@ pass2(FILE *f)
 		Label *l;
 		if(w[0] == '@') continue;
 		if(cmnt(w, &skip)) continue;
-		if(w[0] == '|')
-			p.ptr = shex(w + 1);
-		else if(w[0] == ':')
-			fscanf(f, "%s", w);
-		else if(w[0] == ';')
-			fscanf(f, "%s", w);
-		else if(w[0] == '"')
-			pushtext(w + 1);
-		else if(w[0] == '#')
-			pushshort(shex(w + 1) & 0xff, 1);
-		else if((l = findlabel(w + 1)))
-			pushshort(l->addr, w[0] == ',');
-		else if((op = findoperator(w)) || scmp(w, "BRK"))
-			pushbyte(op, 0);
-		else if(sihx(w + 1) && slen(w + 1) == 2)
-			pushbyte(shex(w + 1), w[0] == ',');
-		else if(sihx(w + 1) && slen(w + 1) == 4)
-			pushshort(shex(w + 1), w[0] == ',');
-		else
-			return error("Unknown label", w);
+		/* clang-format off */
+		if(w[0] == '|') p.ptr = shex(w + 1);
+		else if(w[0] == ':') fscanf(f, "%s", w);
+		else if(w[0] == ';') fscanf(f, "%s", w);
+		else if(w[0] == '+' && sihx(w + 1) && slen(w + 1) == 2) pushbyte((Sint8)shex(w + 1), 1);
+		else if(w[0] == '+' && sihx(w + 1) && slen(w + 1) == 4) pushshort((Sint16)shex(w + 1), 1);
+		else if(w[0] == '-' && sihx(w + 1) && slen(w + 1) == 2) pushbyte((Sint8)(shex(w + 1) * -1), 1);
+		else if(w[0] == '-' && sihx(w + 1) && slen(w + 1) == 4) pushshort((Sint16)(shex(w + 1) * -1), 1);
+		else if(w[0] == '"') pushtext(w + 1);
+		else if(w[0] == '#') pushshort(shex(w + 1) & 0xff, 1);
+		else if((l = findlabel(w + 1))) pushshort(l->addr, w[0] == ',');
+		else if((op = findoperator(w)) || scmp(w, "BRK")) pushbyte(op, 0);
+		else if(sihx(w + 1) && slen(w + 1) == 2) pushbyte(shex(w + 1), w[0] == ',');
+		else if(sihx(w + 1) && slen(w + 1) == 4) pushshort(shex(w + 1), w[0] == ',');
+		else return error("Unknown label", w);
+		/* clang-format on */
 	}
 	return 1;
 }
diff --git a/build.sh b/build.sh
index fe00044..eba54f1 100755
--- a/build.sh
+++ b/build.sh
@@ -24,5 +24,5 @@ rm -f ./bin/emulator
 cc -std=c89 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werror=implicit-int -Werror=incompatible-pointer-types -Werror=int-conversion -Wvla -g -Og -fsanitize=address -fsanitize=undefined uxn.c emulator.c -L/usr/local/lib -lSDL2 -o bin/emulator
 
 # run
-./bin/assembler examples/test.usm bin/boot.rom
+./bin/assembler examples/line.usm bin/boot.rom
 ./bin/emulator bin/boot.rom
diff --git a/etc/usm.sublime-syntax b/etc/usm.sublime-syntax
index 6f484a9..3c288b8 100644
--- a/etc/usm.sublime-syntax
+++ b/etc/usm.sublime-syntax
@@ -21,6 +21,12 @@ contexts:
     - match: '\|(\S+)\s?'
       scope: punctuation.definition
       pop: true
+    - match: '\+(\S+)\s?'
+      scope: keyword.control
+      pop: true
+    - match: '\-(\S+)\s?'
+      scope: keyword.control
+      pop: true
 
   strings:
     - match: '\:(\S+)\s?'
@@ -35,6 +41,9 @@ contexts:
     - match: '\,(\S+)\s?'
       scope: keyword.control
       pop: true
+    - match: '\#(\S+)\s?'
+      scope: keyword.control
+      pop: true
     - match: '\.(\S+)\s?'
       scope: keyword.control
       pop: true
diff --git a/examples/benchmark.usm b/examples/benchmark.usm
index d9963bd..8ad7b56 100644
--- a/examples/benchmark.usm
+++ b/examples/benchmark.usm
@@ -22,6 +22,18 @@
 ,1234 ,1233 GTH^ #0e STR
 ,1234 ,1235 LTH^ #0f STR
 
+BRK
+
+@diff8 ( result of abs sub )
+	OVR OVR GTH ,diff8sub ROT JMP? POP^
+	SWP @diff8sub SUB
+RTS
+
+@diff16 ( result of abs sub16 )
+	OVR^ OVR^ GTH^ ,diff16sub ROT JMP? POP^
+	SWP^ @diff16sub SUB^
+RTS
+
 |c000 @FRAME BRK 
 |d000 @ERROR BRK 
 |FFFA .RESET .FRAME .ERROR
diff --git a/examples/line.usm b/examples/line.usm
index c7bebe4..bc053c5 100644
--- a/examples/line.usm
+++ b/examples/line.usm
@@ -5,6 +5,8 @@
 
 ;x_ 2 ;y_ 2 ;x0 2 ;y0 2 ;x1 2 ;y1 2 ;color 1
 
+;dx 2 ;dy 2 ;err 2 ;err2 2
+
 |0100 @RESET
 
 	( set dev/write to screen ) 
@@ -13,9 +15,10 @@
 
 	( init positions )
 	,0020 ,x0 STR^ ,0018 ,y0 STR^
-	,0030 ,x1 STR^ ,0048 ,y1 STR^
+	,0060 ,x1 STR^ ,0048 ,y1 STR^
 	,x0 LDR^ ,x_ STR^ ,y0 LDR^ ,y_ STR^
 
+
 	( draw control points )
 	,02 ,color STR
 	,x0 LDR^ ,y0 LDR^ ,putpixel JSR
@@ -39,6 +42,11 @@ BRK
 	,00 IOW  ( redraw byte )
 	RTS
 
+@diff16
+	OVR^ OVR^ GTH^ ,diff16sub ROT JMP? POP^
+	SWP^ @diff16sub SUB^
+RTS
+
 |c000 @FRAME BRK 
 |d000 @ERROR BRK 
 |FFFA .RESET .FRAME .ERROR
diff --git a/examples/test.usm b/examples/test.usm
index ef17d85..31d1282 100644
--- a/examples/test.usm
+++ b/examples/test.usm
@@ -3,13 +3,17 @@
 :dev/r fff8 ( std read port )
 :dev/w fff9 ( std write port )
 
+;x 2
+
 |0100 @RESET 
 
-	,00 ,dev/w STR ( set dev/write to console ) 
+	,00 ,dev/w STR ( set dev/write to console )
 
+	-12 +02 LTH!
 
 BRK
 
+
 |c000 @FRAME BRK
 |d000 @ERROR BRK 
 |FFFA .RESET .FRAME .ERROR
diff --git a/uxn.c b/uxn.c
index 31c9a0f..6d284da 100644
--- a/uxn.c
+++ b/uxn.c
@@ -33,7 +33,7 @@ Uint16 peek16(St8 *s, Uint8 a) { return peek8(s, a * 2) + (peek8(s, a * 2 + 1) <
 void op_brk(Uxn *u) { setflag(&u->status,FLAG_HALT, 1); }
 void op_li1(Uxn *u) { u->literal += 1; }
 void op_lix(Uxn *u) { u->literal += u->ram.dat[u->ram.ptr++]; }
-void op_nop(Uxn *u) { printf("%02x\n", pop8(&u->wst)); }
+void op_nop(Uxn *u) { printf("0x%02x ", pop8(&u->wst)); }
 void op_ior(Uxn *u) { Device *dev = &u->dev[mempeek8(&u->ram, u->devr)]; if(dev) push8(&u->wst, dev->read(dev, pop8(&u->wst))); }
 void op_iow(Uxn *u) { Uint8 a = pop8(&u->wst); Device *dev = &u->dev[mempeek8(&u->ram, u->devw)]; if(dev) dev->write(dev, a); }
 void op_ldr(Uxn *u) { Uint16 a = pop16(&u->wst); push8(&u->wst, mempeek8(&u->ram, a)); }
@@ -52,14 +52,14 @@ void op_and(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst,
 void op_ora(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b | a); }
 void op_rol(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b << a); }
 /* Arithmetic */
-void op_add(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b + a); }
-void op_sub(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b - a); }
-void op_mul(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b * a); }
-void op_div(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b / a); }
-void op_equ(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b == a); }
-void op_neq(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b != a); }
-void op_gth(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b > a); }
-void op_lth(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, b < a); }
+void op_add(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b + (Sint8)a : b + a); }
+void op_sub(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b - (Sint8)a : b - a); }
+void op_mul(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b * (Sint8)a : b * a); }
+void op_div(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b / (Sint8)a : b / a); }
+void op_equ(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b == (Sint8)a : b == a); }
+void op_neq(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b != (Sint8)a : b != a); }
+void op_gth(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b > (Sint8)a : b > a); }
+void op_lth(Uxn *u) { Uint8 a = pop8(&u->wst), b = pop8(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b < (Sint8)a : b < a); }
 /* --- */
 void op_nop16(Uxn *u) { printf("%04x\n", pop16(&u->wst)); }
 void op_ior16(Uxn *u) { Uint8 a = pop8(&u->wst); Device *dev = &u->dev[mempeek8(&u->ram, u->devr)]; if(dev) push16(&u->wst, (dev->read(dev, a) << 8) + dev->read(dev, a + 1)); }
@@ -76,14 +76,14 @@ void op_and16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u
 void op_ora16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, b | a); }
 void op_rol16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, b << a); }
 /* Arithmetic(16-bits) */
-void op_add16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, b + a); }
-void op_sub16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, b - a); }
-void op_mul16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, b * a); }
-void op_div16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, b / a); }
-void op_equ16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push8(&u->wst, b == a); }
-void op_neq16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push8(&u->wst, b != a); }
-void op_gth16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push8(&u->wst, b > a); }
-void op_lth16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push8(&u->wst, b < a); }
+void op_add16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b + (Sint8)a : b + a); }
+void op_sub16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b - (Sint8)a : b - a); }
+void op_mul16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b * (Sint8)a : b * a); }
+void op_div16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push16(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b / (Sint8)a : b / a); }
+void op_equ16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b == (Sint8)a : b == a); }
+void op_neq16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b != (Sint8)a : b != a); }
+void op_gth16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b > (Sint8)a : b > a); }
+void op_lth16(Uxn *u) { Uint16 a = pop16(&u->wst), b = pop16(&u->wst); push8(&u->wst, getflag(&u->status, FLAG_SIGN) ? (Sint8)b < (Sint8)a : b < a); }
 
 void (*ops[])(Uxn *u) = {
 	op_brk, op_nop, op_li1, op_lix, op_ior, op_iow, op_ldr, op_str, 
@@ -133,7 +133,7 @@ opcuxn(Uxn *u, Uint8 instr)
 {
 	Uint8 op = instr & 0x1f;
 	setflag(&u->status, FLAG_SHORT, (instr >> 5) & 1);
-	setflag(&u->status, FLAG_SIGN, (instr >> 6) & 1); /* usused */
+	setflag(&u->status, FLAG_SIGN, (instr >> 6) & 1);
 	setflag(&u->status, FLAG_COND, (instr >> 7) & 1);
 	if(getflag(&u->status, FLAG_SHORT))
 		op += 32;
diff --git a/uxn.h b/uxn.h
index 142b15f..5bf33d3 100644
--- a/uxn.h
+++ b/uxn.h
@@ -12,7 +12,9 @@ WITH REGARD TO THIS SOFTWARE.
 */
 
 typedef unsigned char Uint8;
+typedef signed char Sint8;
 typedef unsigned short Uint16;
+typedef signed short Sint16;
 
 #define FLAG_HALT 0x01
 #define FLAG_SHORT 0x02