@@ -27,6 +27,10 @@ cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn

 - `|0010`, move to position in the program

 - `"hello`, push literal bytes for word "hello"

+### Operator modes

+

+- `,1234 ,0001 ADD^`, 16-bits operators have the short flag `^`.

+

 ```

 ( hello world )

@@ -6,14 +6,19 @@

 |0100 @RESET

-"hello

+@word1 "hello_word ( len: 0x0b )

 @loop

-	,dev1w STR

-	,incr JSU ( call incr )

-	,05 NEQ ,loop ROT JSC

+	,dev1w STR ( write to stdout )

+	,incr JSU ( increment itr )

+	,word1 ,strlen JSU ( get strlen )

+	NEQ ,loop ROT JSC ( loop != strlen )

-BRK ( RESET )

+BRK

+

+@strlen

+	,0001 ADD^ PEK

+	RTS

 @incr

 	,iterator LDR

@@ -21,7 +26,7 @@ BRK ( RESET )

 	,iterator STR 

 	,iterator LDR

 	RTS

-	

+

 |c000 @FRAME BRK 

 |d000 @ERROR BRK 

 |FFFA .RESET .FRAME .ERROR

new file mode 100644

@@ -0,0 +1,32 @@

+( hello world )

+

+;iterator

+:dev1r FFF0

+:dev1w FFF1

+

+|0100 @RESET

+

+@word1 "hello_word ( len: 0x0b )

+

+@loop

+	,dev1w STR ( write to stdout )

+	,incr JSU ( increment itr )

+	,word1 ,strlen JSU ( get strlen )

+	NEQ ,loop ROT JSC ( loop != strlen )

+

+BRK

+

+@strlen

+	,0001 ADD^ PEK

+	RTS

+

+@incr

+	,iterator LDR

+	,01 ADD

+	,iterator STR 

+	,iterator LDR

+	RTS

+

+|c000 @FRAME BRK 

+|d000 @ERROR BRK 

+|FFFA .RESET .FRAME .ERROR

@@ -12,7 +12,7 @@ WITH REGARD TO THIS SOFTWARE.

 */

 #define FLAG_HALT 0x01

-#define FLAG_ZERO 0x02

+#define FLAG_SHORT 0x02

 #define FLAG_CARRY 0x04

 #define FLAG_TRAPS 0x08

@@ -96,6 +96,7 @@ Uint8 rampeek8(Uint16 s) { return cpu.ram.dat[s] & 0xff; }

 Uint8 mempeek8(Uint16 s) { return cpu.rom.dat[s]; }

 Uint16 mempeek16(Uint16 s) { return (cpu.rom.dat[s] << 8) + (cpu.rom.dat[s+1] & 0xff); }

 void wspush8(Uint8 b) { cpu.wst.dat[cpu.wst.ptr++] = b; }

+void wspush16(Uint16 s) { wspush8(s >> 8); wspush8(s & 0xff); }

 Uint8 wspop8(void) { return cpu.wst.dat[--cpu.wst.ptr]; }

 Uint16 wspop16(void) { return wspop8() + (wspop8() << 8); }

 Uint8 wspeek8(void) { return cpu.wst.dat[cpu.wst.ptr - 1]; }

@@ -116,24 +117,31 @@ void op_jmc() { if(wspop8()) op_jmu(); }

 void op_jsc() { if(wspop8()) op_jsu(); }

 void op_equ() { wspush8(wspop8() == wspop8()); }

 void op_neq() { wspush8(wspop8() != wspop8()); }

-void op_gth() {	wspush8(wspop8() < wspop8()); }

-void op_lth() {	wspush8(wspop8() > wspop8()); }

-void op_and() {	wspush8(wspop8() & wspop8()); }

-void op_ora() {	wspush8(wspop8() | wspop8()); }

+void op_gth() { wspush8(wspop8() < wspop8()); }

+void op_lth() { wspush8(wspop8() > wspop8()); }

+void op_and() { wspush8(wspop8() & wspop8()); }

+void op_ora() { wspush8(wspop8() | wspop8()); }

 void op_rol() { wspush8(wspop8() << 1); }

 void op_ror() { wspush8(wspop8() >> 1); }

-void op_add() { wspush8(wspop8() + wspop8()); }

+void op_add() { 

+	if(getflag(FLAG_SHORT))

+		wspush16(wspop16() + wspop16()); 

+	else

+		wspush8(wspop8() + wspop8()); 

+}

 void op_sub() { wspush8(wspop8() - wspop8()); }

 void op_mul() { wspush8(wspop8() * wspop8()); }

 void op_div() { wspush8(wspop8() / wspop8()); }

 void op_ldr() { wspush8(cpu.ram.dat[wspop16()]); }

 void op_str() { cpu.ram.dat[wspop16()] = wspop8(); }

+void op_pek() { wspush8(cpu.rom.dat[wspop16()]); }

+void op_pok() { printf("TODO:\n");}

-void (*ops[])(void) = {

+void (*ops[])() = {

 	op_brk, op_rts, op_lit, op_drp, op_dup, op_swp, op_ovr, op_rot, 

 	op_jmu, op_jsu, op_jmc, op_jsc, op_equ, op_neq, op_gth, op_lth, 

 	op_and, op_ora, op_rol, op_ror, op_add, op_sub, op_mul, op_div,

-	op_ldr, op_str, op_brk, op_brk, op_brk, op_brk, op_brk, op_brk

+	op_ldr, op_str, op_pek, op_pok, op_brk, op_brk, op_brk, op_brk

 };

 Uint8 opr[][2] = {

@@ -162,9 +170,9 @@ reset(void)

 }

 int

-error(char *name)

+error(char *name, int id)

 {

-	printf("Error: %s, at 0x%04x\n", name, cpu.counter);

+	printf("Error: %s[%04x], at 0x%04x\n", name, id, cpu.counter);

 	return 0;

 }

@@ -177,31 +185,48 @@ device1(Uint8 *read, Uint8 *write)

 	return 0;

 }

+void

+opc(Uint8 src, Uint8 *op, Uint8 *mode)

+{

+	*op = src;

+	*op &= ~(1 << 5);

+	*op &= ~(1 << 6);

+	*op &= ~(1 << 7);

+	*mode = src;

+	*mode &= ~(1 << 0);

+	*mode &= ~(1 << 1);

+	*mode &= ~(1 << 2);

+	*mode &= ~(1 << 3);

+}

+

 int

 eval(void)

 {

 	Uint8 instr = cpu.rom.dat[cpu.rom.ptr++];

+	Uint8 op, opmode;

+	/* when literal */

 	if(cpu.literal > 0) {

 		wspush8(instr);

 		cpu.literal--;

 		return 1;

 	}

-	if(instr < 32) {

-		if(cpu.wst.ptr < opr[instr][0])

-			return error("Stack underflow");

-		/* TODO stack overflow */

-		(*ops[instr])();

-	}

-	if(instr > 0x10)

-		setflag(FLAG_ZERO, 0);

-	if(cpu.counter == 128) {

-		return error("Reached bounds");

-	}

+	/* when opcode */

+	opc(instr, &op, &opmode);

+	setflag(FLAG_SHORT, (instr >> 5) & 1);

+	if((instr >> 6) & 1)

+		printf("Unused flag: %02x\n", instr);

+	if((instr >> 7) & 1)

+		printf("Unused flag: %02x\n", instr);

+	/* TODO: setflag(FLAG_B, (instr >> 6) & 1); */

+	/* TODO: setflag(FLAG_C, (instr >> 7) & 1); */

+	if(cpu.wst.ptr < opr[op][0])

+		return error("Stack underflow", op);

+	(*ops[op])();

 	cpu.counter++;

 	return 1;

 }

-void

+int

 start(FILE *f)

 {

 	reset();

@@ -216,6 +241,8 @@ start(FILE *f)

 		/* experimental */

 		if(cpu.ram.dat[0xfff1])

 			device1(&cpu.ram.dat[0xfff0], &cpu.ram.dat[0xfff1]);

+		if(cpu.counter > 256)

+			return error("Reached bounds", cpu.counter);

 	}

 	/*eval frame */

 	printf("\nPhase: frame\n");

@@ -227,10 +254,11 @@ start(FILE *f)

 	printf("ended @ %d steps | ", cpu.counter);

 	printf("hf: %x zf: %x cf: %x tf: %x\n",

 		getflag(FLAG_HALT) != 0,

-		getflag(FLAG_ZERO) != 0,

+		getflag(FLAG_SHORT) != 0,

 		getflag(FLAG_CARRY) != 0,

 		getflag(FLAG_TRAPS) != 0);

 	printf("\n");

+	return 1;

 }

 int

@@ -238,10 +266,11 @@ main(int argc, char *argv[])

 {

 	FILE *f;

 	if(argc < 2)

-		return error("No input.");

+		return error("No input.", 0);

 	if(!(f = fopen(argv[1], "rb")))

-		return error("Missing input.");

-	start(f);

+		return error("Missing input.", 0);

+	if(!start(f))

+		return error("Program error", 0);

 	/* print result */

 	echos(&cpu.wst, 0x40, "stack");

 	echom(&cpu.ram, 0x40, "ram");

@@ -29,11 +29,11 @@ Label labels[256];

 /* clang-format off */

-char opcodes[][4] = {

+char ops[][4] = {

 	"BRK", "RTS", "LIT", "POP", "DUP", "SWP", "OVR", "ROT",

 	"JMU", "JSU", "JMC", "JSC", "EQU", "NEQ", "GTH", "LTH",

 	"AND", "ORA", "ROL", "ROR", "ADD", "SUB", "MUL", "DIV",

-	"LDR", "STR", "---", "---", "---", "---", "---", "---"

+	"LDR", "STR", "PEK", "POK", "---", "---", "---", "---"

 };

 /* clang-format on */

@@ -162,6 +162,27 @@ findlabel(char *s)

 	return NULL;

 }

+Uint8

+findop(char *s)

+{

+	int i;

+	for(i = 0; i < 32; ++i) {

+		int m = 0;

+		if(ops[i][0] != s[0]) continue;

+		if(ops[i][1] != s[1]) continue;

+		if(ops[i][2] != s[2]) continue;

+		while(s[3 + m]) {

+			char c = s[3 + m];

+			if(c == '^') i |= (1 << 5); /* mode: 16 bits */

+			if(c == '&') i |= (1 << 6); /* mode: unused */

+			if(c == '~') i |= (1 << 7); /* mode: unused */

+			m++;

+		}

+		return i;

+	}

+	return 0;

+}

+

 #pragma mark - Parser

 int

@@ -171,16 +192,6 @@ error(char *name, char *id)

 	return 0;

 }

-Uint8

-findop(char *s)

-{

-	int i;

-	for(i = 0; i < 32; ++i)

-		if(scmp(opcodes[i], s))

-			return i;

-	return 0;

-}

-

 int

 makelabel(char *id, Uint16 addr)

 {

@@ -210,7 +221,6 @@ pass1(FILE *f)

 	char w[64];

 	while(fscanf(f, "%s", w) == 1) {

 		if(iscomment(w, &skip)) continue;

-		suca(w);

 		if(w[0] == '@' && !makelabel(w + 1, addr))

 			return error("Pass1 failed", w);

 		if(w[0] == ';' && !makelabel(w + 1, vars++))

@@ -253,7 +263,6 @@ pass2(FILE *f)

 		Label *l;

 		if(w[0] == '@') continue;

 		if(w[0] == ';') continue;

-		suca(w);

 		if(iscomment(w, &skip)) continue;

 		if(w[0] == '|')

 			p.ptr = shex(w + 1);

@@ -261,10 +270,10 @@ pass2(FILE *f)

 			fscanf(f, "%s", w);

 		else if(w[0] == '"')

 			pushword(w + 1);

-		else if((op = findop(w)) || scmp(w, "BRK"))

-			pushbyte(op, 0);

 		else if((l = findlabel(w + 1)))

 			pushshort(l->addr, w[0] == ',');

+		else if((op = findop(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)