diff --git a/.clang-format b/.clang-format
index 67c9a1b..0ad3042 100644
--- a/.clang-format
+++ b/.clang-format
@@ -1,7 +1,9 @@
 AlignAfterOpenBracket: DontAlign
 AlignEscapedNewlines: DontAlign
+AlignOperands: DontAlign
 AllowShortBlocksOnASingleLine: Empty
 AllowShortCaseLabelsOnASingleLine: true
+AllowShortEnumsOnASingleLine: true
 AllowShortIfStatementsOnASingleLine: false
 AllowShortLoopsOnASingleLine: false
 AlwaysBreakAfterDefinitionReturnType: TopLevel
diff --git a/build.sh b/build.sh
index ddb3cad..7fd17c9 100755
--- a/build.sh
+++ b/build.sh
@@ -7,10 +7,11 @@ clang-format -i uxn.c
 # remove old
 rm -f ./uxnasm
 rm -f ./uxn
+rm -f ./boot.rom
 
 # debug(slow)
 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 uxnasm.c -o uxnasm
-# 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 -o uxn
+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 -o uxn
 
 # build(fast)
 # cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn
@@ -19,5 +20,5 @@ cc -std=c89 -DDEBUG -Wall -Wno-unknown-pragmas -Wpedantic -Wshadow -Wextra -Werr
 # echo "Size: $(du -sk ./uxn)"
 
 # run
-./uxnasm program.usm program.rom
-# ./uxn program.rom
+./uxnasm example.usm boot.rom
+./uxn boot.rom
diff --git a/example.usm b/example.usm
new file mode 100644
index 0000000..a600afd
--- /dev/null
+++ b/example.usm
@@ -0,0 +1 @@
+{ 25 26 27 28 } SWP POP DUP BRK
\ No newline at end of file
diff --git a/program.usm b/program.usm
deleted file mode 100644
index cd4b5dd..0000000
--- a/program.usm
+++ /dev/null
@@ -1 +0,0 @@
-LIT 25 26 LIT DUP ADD BRK
\ No newline at end of file
diff --git a/uxn.c b/uxn.c
index 6c88ec0..2c13b42 100644
--- a/uxn.c
+++ b/uxn.c
@@ -11,20 +11,38 @@ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 WITH REGARD TO THIS SOFTWARE.
 */
 
+#define FLAG_HALT 0x01
+#define FLAG_ZERO 0x02
+#define FLAG_CARRY 0x04
+#define FLAG_TRAPS 0x08
+
 #define STACK_DEPTH 256
-#define ECHO 1
 
 typedef unsigned char Uint8;
-typedef unsigned char Uint16;
 
 typedef struct {
-
+	Uint8 literal;
+	Uint8 status, counter;
+	Uint8 memory[STACK_DEPTH];
+	Uint8 mptr, sptr;
+	Uint8 stack[STACK_DEPTH];
+	Uint8 address[STACK_DEPTH];
 } Computer;
 
-Uint8 sptr;
-Uint8 stack[STACK_DEPTH];
-Uint8 address[STACK_DEPTH];
-Uint16 memory[STACK_DEPTH];
+void
+setflag(Computer *cpu, char flag, int b)
+{
+	if(b)
+		cpu->status |= flag;
+	else
+		cpu->status &= (~flag);
+}
+
+int
+getflag(Computer *cpu, char flag)
+{
+	return cpu->status & flag;
+}
 
 void
 echo(Uint8 *s, Uint8 len, char *name)
@@ -34,51 +52,79 @@ echo(Uint8 *s, Uint8 len, char *name)
 	for(i = 0; i < len; ++i) {
 		if(i % 16 == 0)
 			printf("\n");
-		if(sptr == i)
-			printf("[%02x]", s[i]);
-		else
-			printf(" %02x ", s[i]);
+		printf("%02x ", s[i]);
 	}
-	printf("\n");
+	printf("\n\n");
 }
 
 void
-op_push(Uint8 *s, Uint8 v)
+op_push(Uint8 *s, Uint8 *ptr, Uint8 v)
 {
-	s[sptr++] = v;
+	s[*ptr] = v;
+	(*ptr) += 1;
 }
 
 void
-op_pop(Uint8 *s)
+op_pop(Uint8 *s, Uint8 *ptr)
 {
-	s[sptr--] = 0x00;
+	s[*ptr--] = 0x00;
 }
 
 void
 reset(Computer *cpu)
 {
+	int i;
+	cpu->status = 0x00;
+	cpu->counter = 0x00;
+	cpu->mptr = 0x00;
+	cpu->sptr = 0x00;
+	cpu->literal = 0x00;
+	for(i = 0; i < 256; i++)
+		cpu->stack[i] = 0x00;
 }
 
 int
-disk(Computer *cpu, FILE *f)
+error(char *name)
 {
-	int i;
-	unsigned short buffer[256];
-	reset(cpu);
-	if(!fread(buffer, sizeof(buffer), 1, f))
-		return 0;
-
-	for(i = 0; i < 128; i++) {
-		cpu->memory[i * 2] |= (buffer[i] >> 8) & 0xFF;
-		cpu->memory[i * 2 + 1] |= buffer[i] & 0xFF;
-	}
-
-	return 1;
+	printf("Error: %s\n", name);
+	return 0;
 }
 
 void
-run(Computer *cpu, int debug)
+load(Computer *cpu, FILE *f)
 {
+	fread(cpu->memory, sizeof(cpu->memory), 1, f);
+}
+
+void
+eval(Computer *cpu)
+{
+	Uint8 instr = cpu->memory[cpu->mptr++];
+
+	if(cpu->literal > 0) {
+		printf("push: %02x[%d](%d)\n", instr, cpu->literal, cpu->sptr);
+		op_push(cpu->stack, &cpu->sptr, instr);
+		cpu->literal--;
+		return;
+	}
+	switch(instr) {
+	case 0x0: setflag(cpu, FLAG_HALT, 1); break;
+	case 0x1: cpu->literal += 4; break;
+	default: printf("Unknown instruction: #%02x\n", instr);
+	}
+}
+
+void
+run(Computer *cpu)
+{
+	int i;
+	while((cpu->status & FLAG_HALT) == 0)
+		eval(cpu);
+	/* debug */
+	printf("ended @ %d  |  ", cpu->counter);
+	for(i = 0; i < 4; i++)
+		printf("%d-", (cpu->status & (1 << i)) != 0);
+	printf("\n\n");
 }
 
 int
@@ -90,11 +136,11 @@ main(int argc, char *argv[])
 		return error("No input.");
 	if(!(f = fopen(argv[1], "rb")))
 		return error("Missing input.");
-	if(!disk(&cpu, f))
-		return error("Unreadable input.");
-	run(&cpu, ECHO);
+	reset(&cpu);
+	load(&cpu, f);
+	run(&cpu);
 	/* print result */
-	echo(stack, 0x40, "stack");
-	echo(memory, 0x40, "memory");
+	echo(cpu.stack, 0x40, "stack");
+	echo(cpu.memory, 0x40, "memory");
 	return 0;
 }
diff --git a/uxnasm.c b/uxnasm.c
index 37d3232..a94fd54 100644
--- a/uxnasm.c
+++ b/uxnasm.c
@@ -20,7 +20,39 @@ typedef struct {
 	Uint8 data[PRGLEN];
 } Program;
 
-char opcodes[][4] = {"BRK", "LIT", "DUP", "DRP", "SWP", "SLP", "PSH", "POP", "JMP", "JSR", "RST", "BEQ", "EQU", "NEQ", "LTH", "GTH"};
+char opcodes[][4] = {
+	"BRK",
+	"LIT",
+	"DUP",
+	"DRP",
+	"SWP",
+	"SLP",
+	"PSH",
+	"POP", /* --- */
+	"JMP",
+	"JSR",
+	"RST",
+	"BEQ",
+	"EQU",
+	"NEQ",
+	"LTH",
+	"GTH", /* --- */
+	"---",
+	"---",
+	"---",
+	"---",
+	"---",
+	"---",
+	"---",
+	"---", /* --- */
+	"---",
+	"---",
+	"---",
+	"---",
+	"---",
+	"---",
+	"---",
+	"---"};
 
 Program p;
 
@@ -65,34 +97,22 @@ Uint8
 getopcode(char *s)
 {
 	int i;
+	if(s[0] == '{') /* TODO catch closing */
+		return 0x01;
 	for(i = 0; i < 16; ++i)
 		if(scmp(opcodes[i], suca(s)))
 			return i;
 	return 0xff;
 }
 
-void
-echo(Uint8 *s, Uint8 len, Uint8 ptr, char *name)
-{
-	int i;
-	printf("%s\n", name);
-	for(i = 0; i < len; ++i) {
-		if(i % 16 == 0)
-			printf("\n");
-		if(ptr == i)
-			printf("[%02x]", s[i]);
-		else
-			printf(" %02x ", s[i]);
-	}
-	printf("\n");
-}
-
 void
 pass1(FILE *f)
 {
 	char word[64];
 	while(fscanf(f, "%s", word) == 1) {
 		int op = getopcode(word);
+		if(word[0] == '}')
+			continue;
 		if(op == 0xff)
 			op = shex(word);
 		p.data[p.ptr++] = op;
@@ -117,6 +137,5 @@ main(int argc, char *argv[])
 	pass1(f);
 	fwrite(p.data, sizeof(p.data), 1, fopen(argv[2], "wb"));
 	fclose(f);
-	echo(p.data, 0x40, 0, "program");
 	return 0;
 }