@@ -17,20 +17,20 @@ cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn

 ```

 < conditionals >

-+03 +02    ADD 

-+05        EQU

+0302	ADD 

+05		EQU

-.there     JMQ

+.there	JMQ

 :here

-  < when not equal >

-  +ee

-  BRK

+	< when not equal >

+	ee

+	BRK

 :there

-  < when is equal >

-  +ff

-  BRK

+	< when is equal >

+	ff

+	BRK

 ```

 ## Mission

@@ -44,10 +44,6 @@ cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn

 - Print word to stdout

 - Draw pixel to screen

 - Detect mouse click

-- 16 bits addressing

-- jumping to subroutine should be relative

-- Implement addressing

-- Implement 16 bits operations

 - Jumps should be relative

 - Catch overflow/underflow

 - Audo-detect literals length.

@@ -55,6 +51,13 @@ cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn

 - Build PPU

 - Interrupts

+### 16 Bit Missions

+

+- 16 bits addressing

+- jumping to subroutine should be relative

+- Implement addressing

+- Implement 16 bits operations

+

 ## Refs

 https://code.9front.org/hg/plan9front/file/a7f9946e238f/sys/src/games/nes/cpu.c

@@ -1,16 +1,16 @@

 < conditionals >

-+03 +02    ADD 

-+05        EQU

+0302	ADD 

+05		EQU

-.there     JMQ

+.there	JMQ

 :here

-  < when not equal >

-  +ee

-  BRK

+	< when not equal >

+	ee

+	BRK

 :there

-  < when is equal >

-  +ff

-  BRK

+	< when is equal >

+	ff

+	BRK

@@ -1,4 +1,4 @@

 < core >

-+12 +34 ADD

+01 ADD

@@ -1,7 +1,7 @@

-< conditionals >

+< jump >

-.end       JMP

+.end JMP BRK

-:end

-  +ff

-  BRK

+:end 

+	ff

+	BRK

deleted file mode 100644

@@ -1,18 +0,0 @@

-< comment >

-

-.deep JSR [4 6 7 8 9 ] BRK

-

-:deep

-	[2 1 2 ] 

-	.deeper JSR 

-	RTS

-

-:deeper

-	[3 3 4 5 ] 

-	.deeperyet JSR

-	RTS

-

-:deeperyet

-	[2 aa bb ]

-	RTS

-	

\ No newline at end of file

@@ -2,17 +2,17 @@

 :begin

   .addall JSR ADD ADD

-  +06 EQU .isequal JSR

+  06 EQU .isequal JSR

   BRK

 :add1

-  +01 RTS

+  01 RTS

 :add2

-  +02 RTS

+  02 RTS

 :add3

-  +03 RTS

+  03 RTS

 :addall

   .add1 JSR

@@ -21,5 +21,5 @@

   RTS

 :isequal

-  .addall JSR +ff

+  .addall JSR ff

   RTS

@@ -19,15 +19,15 @@ WITH REGARD TO THIS SOFTWARE.

 #define STACK_DEPTH 256

 typedef unsigned char Uint8;

+typedef unsigned short Uint16;

 typedef struct {

-	Uint8 literal;

-	Uint8 status, counter;

-	Uint8 memory[STACK_DEPTH];

+	Uint8 literal, status;

 	Uint8 mptr, sptr, rsptr;

+	Uint8 memory[STACK_DEPTH];

 	Uint8 stack[STACK_DEPTH];

 	Uint8 rstack[STACK_DEPTH];

-	Uint8 address[STACK_DEPTH];

+	Uint16 counter;

 } Computer;

 Computer cpu;

@@ -92,7 +92,7 @@ rspop(void)

 void op_brk() { setflag(FLAG_HALT, 1); }

 void op_rts() {	cpu.mptr = rspop(); }

-void op_lit() { cpu.literal += 1; }

+void op_lit() { cpu.literal += cpu.memory[cpu.mptr++]; }

 void op_drp() { spop(); }

 void op_dup() { spush(cpu.stack[cpu.sptr - 1]); }

 void op_swp() { Uint8 b = spop(), a = spop(); spush(b); spush(a); }

@@ -100,8 +100,8 @@ void op_ovr() { spush(cpu.stack[cpu.sptr - 2]); }

 void op_rot() { Uint8 c = spop(),b = spop(),a = spop(); spush(b); spush(c); spush(a); }

 void op_jmp() { cpu.mptr = spop(); }

 void op_jsr() { rspush(cpu.mptr); cpu.mptr = spop(); }

-void op_jmq() { if(getflag(FLAG_ZERO)){ op_jmp(); } setflag(FLAG_ZERO,0); }

-void op_jsq() { if(getflag(FLAG_ZERO)){ op_jsr(); } setflag(FLAG_ZERO,0); }

+void op_jmq() { Uint8 a = spop(); if(getflag(FLAG_ZERO)){ cpu.mptr = a; } setflag(FLAG_ZERO,0); }

+void op_jsq() { Uint8 a = spop(); if(getflag(FLAG_ZERO)){ rspush(cpu.mptr); cpu.mptr = a; } setflag(FLAG_ZERO,0); }

 void op_equ() { setflag(FLAG_ZERO, spop() == spop()); }

 void op_neq() { setflag(FLAG_ZERO, spop() != spop()); }

 void op_lth() {	setflag(FLAG_ZERO, spop() < spop()); }

@@ -120,6 +120,13 @@ void (*ops[])(void) = {

 	op_jmp, op_jsr, op_jmq, op_jsq, op_equ, op_neq, op_gth, op_lth, 

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

+Uint8 opr[][2] = {

+	{0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0},

+	{0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0},

+	{0,0}, {0,0}, {0,0}, {0,0}, {2,1}, {0,0}, {0,0}, {0,0},

+	{0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0},

+};

+

 /* clang-format on */

 void

@@ -148,38 +155,40 @@ load(FILE *f)

 	fread(cpu.memory, sizeof(cpu.memory), 1, f);

 }

-void

+int

 eval()

 {

 	Uint8 instr = cpu.memory[cpu.mptr++];

 	if(cpu.literal > 0) {

 		spush(instr);

 		cpu.literal--;

-		return;

+		return 1;

 	}

-	if(instr < 24)

+	if(instr < 24) {

+		if(cpu.sptr < opr[instr][0])

+			return error("Stack underflow");

+		/* TODO stack overflow */

 		(*ops[instr])();

+	}

 	if(instr > 0x10)

 		setflag(FLAG_ZERO, 0);

+	cpu.counter++;

+	return 1;

 }

 void

 run(void)

 {

-	int i;

-	while((cpu.status & FLAG_HALT) == 0)

-		eval(cpu);

+	while(!(cpu.status & FLAG_HALT) && eval(cpu))

+		;

 	/* debug */

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

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

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

-		getflag(FLAG_HALT),

-		getflag(FLAG_ZERO),

-		getflag(FLAG_CARRY),

-		getflag(FLAG_TRAPS));

-	printf("\n\n");

-	for(i = 0; i < 4; i++)

-		printf("%d-", (cpu.status & (1 << i)) != 0);

-	printf("\n\n");

+		getflag(FLAG_HALT) != 0,

+		getflag(FLAG_ZERO) != 0,

+		getflag(FLAG_CARRY) != 0,

+		getflag(FLAG_TRAPS) != 0);

+	printf("\n");

 }

 int

@@ -29,33 +29,14 @@ typedef struct {

 int labelslen;

 Label labels[256];

+/* clang-format off */

+

 char opcodes[][4] = {

-	"BRK",

-	"RTS",

-	"LIT",

-	"POP",

-	"DUP",

-	"SWP",

-	"OVR",

-	"ROT",

-	/* */

-	"JMP",

-	"JSR",

-	"JMQ",

-	"JSQ",

-	"EQU",

-	"NEQ",

-	"LTH",

-	"GTH",

-	"---",

-	"---",

-	"---",

-	"---",

-	"ADD",

-	"SUB",

-	"MUL",

-	"DIV"

-	/* */};

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

+	"JMP", "JSR", "JMQ", "JSQ", "EQU", "NEQ", "LTH", "GTH",

+	"AND", "ORA", "ROL", "ROR", "ADD", "SUB", "MUL", "DIV"};

+

+/* clang-format on */

 Program p;

@@ -81,6 +62,15 @@ scpy(char *src, char *dst, int len) /* string copy */

 	return dst;

 }

+int

+slen(char *s) /* string length */

+{

+	int i = 0;

+	while(s[i] && s[++i])

+		;

+	return i;

+}

+

 char *

 suca(char *s) /* string to uppercase */

 {

@@ -120,11 +110,41 @@ shex(char *s) /* string to num */

 #pragma mark - Parser

 void

-addprg(Uint8 hex)

+pushprg(Uint8 hex)

 {

 	p.data[p.len++] = hex;

 }

+void

+pushlabel(Label *l)

+{

+	pushprg(0x02);

+	pushprg(0x01);

+	pushprg(l->addr);

+}

+

+void

+pushliteral(char *w)

+{

+	int len = slen(w) / 2, value = shex(w);

+	pushprg(0x02);

+	pushprg(len);

+	switch(len) {

+	case 1:

+		pushprg(value);

+		break;

+	case 2:

+		pushprg(value >> 8);

+		pushprg(value);

+		break;

+	case 3:

+		pushprg(value >> 16);

+		pushprg(value >> 8);

+		pushprg(value);

+		break;

+	}

+}

+

 void

 addlabel(char *id, Uint8 addr)

 {

@@ -164,10 +184,9 @@ int

 getlength(char *w)

 {

 	if(findop(w) || scmp(w, "BRK")) return 1;

-	if(w[0] == '.') return 2;

+	if(w[0] == '.') return 3;

 	if(w[0] == ':') return 0;

-	if(w[0] == '+') return 2;

-	if(w[0] == '-') return 2;

+	if(sihx(w)) { return slen(w) / 2 + 2; }

 	printf("Unknown length %s\n", w);

 	return 0;

 }

@@ -209,21 +228,14 @@ pass2(FILE *f)

 		if(word[0] == ':') continue;

 		suca(word);

 		if(comment(word, &skip)) continue;

-		/* literals */

-		if(word[0] == '+' || word[0] == '-')

-			addprg(0x02);

-		if(word[0] == '+')

-			addprg(shex(word + 1));

-		else if(word[0] == '-')

-			addprg((Uint8)(-1 * shex(word + 1)));

-		/* opcodes */

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

-			addprg(op);

-		else if((l = findlabel(word + 1))) {

-			addprg(0x02);

-			addprg(l->addr);

-		} else

-			printf("unknown: %s\n", word);

+		if((op = findop(word)) || scmp(word, "BRK"))

+			pushprg(op);

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

+			pushlabel(l);

+		else if(sihx(word))

+			pushliteral(word);

+		else

+			printf("Unknown label: %s\n", word);

 	}

 }