@@ -34,6 +34,17 @@ $01 < pointer8 >

 :label ADD RTS

 ```

+## Mission

+

+- Loop

+- Conditional example

+- Pointers/Literals

+- Print word to stdout

+- Draw pixel to screen

+- Detect mouse click

+- 16 bits addressing

+- jumping to subroutine should be relative

+

 ## TODOs

 - Implement addressing

@@ -44,6 +55,7 @@ $01 < pointer8 >

 - Audo-detect literals length.

 - SDL Layer Emulator

 - Build PPU

+- Interrupts

 ## Refs

@@ -13,12 +13,6 @@ rm -f ./boot.rom

 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

-# build(fast)

-# cc uxn.c -std=c89 -Os -DNDEBUG -g0 -s -Wall -Wno-unknown-pragmas -o uxn

-

-# Size

-# echo "Size: $(du -sk ./uxn)"

-

 # run

-./uxnasm example.usm boot.rom

+./uxnasm examples/cond.usm boot.rom

 ./uxn boot.rom

new file mode 100644

@@ -0,0 +1,16 @@

+< conditionals >

+

++03 +02    ADD 

++05        EQU

+

+.there     JMQ

+

+:here

+  < when not equal >

+  +ee

+  BRK

+

+:there

+  < when is equal >

+  +ff

+  BRK

new file mode 100644

@@ -0,0 +1,3 @@

+< core >

+

++12 -34

\ No newline at end of file

new file mode 100644

@@ -0,0 +1,7 @@

+< conditionals >

+

+.end       JMP

+

+:end

+  +ff

+  BRK

similarity index 100%

rename from example.usm

rename to examples/rstack.usm

@@ -91,8 +91,8 @@ rspop(void)

 /* clang-format off */

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

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

-void op_nop() { }

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

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

 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_jeq() { if(getflag(FLAG_ZERO)) cpu.mptr = spop(); }

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

+void op_jmq() { if(getflag(FLAG_ZERO)) op_jmp(); }

+void op_jsq() { if(getflag(FLAG_ZERO)) op_jsr(); }

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

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

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

@@ -116,8 +116,8 @@ void op_mul() { spush(spop() * spop()); }

 void op_div() { spush(spop() / spop()); }

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

-	op_brk, op_lit, op_nop, op_drp, op_dup, op_swp, op_ovr, op_rot, 

-	op_jmp, op_jsr, op_jeq, op_rts, op_equ, op_neq, op_gth, op_lth, 

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

+	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};

 /* clang-format on */

@@ -31,8 +31,8 @@ Label labels[256];

 char opcodes[][4] = {

 	"BRK",

+	"RTS",

 	"LIT",

-	"---",

 	"POP",

 	"DUP",

 	"SWP",

@@ -41,8 +41,8 @@ char opcodes[][4] = {

 	/* */

 	"JMP",

 	"JSR",

-	"JEQ",

-	"RTS",

+	"JMQ",

+	"JSQ",

 	"EQU",

 	"NEQ",

 	"LTH",

@@ -164,11 +164,10 @@ int

 getlength(char *w)

 {

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

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

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

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

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

-	if(sihx(w)) return 1;

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

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

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

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

 	return 0;

 }

@@ -205,28 +204,23 @@ pass2(FILE *f)

 	int skip = 0;

 	char word[64];

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

-		Uint8 op;

+		Uint8 op = 0;

 		Label *l;

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

 		suca(word);

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

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

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

-			addprg(0x01);

-			addprg(1);

-			addprg(shex(word + 1));

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

-			addprg(0x01);

+		/* literals */

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

+			addprg(0x02);

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

 			addprg(shex(word + 1));

-		} else if((op = findop(word)))

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

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

+		/* opcodes */

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

 			addprg(op);

-		else if(sihx(word))

-			addprg(shex(word));

-		else if(scmp(word, "BRK"))

-			addprg(0x00);

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

-			addprg(0x01);

-			addprg(1);

+			addprg(0x02);

 			addprg(l->addr);

 		} else

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