Added padding

examples/core.usm

@@ -1,9 +1,29 @@
-( comment )
+( define some variables in the zero-page )
 
 ;var1
 ;var2
 ;var3
 
-,ef ,var2 STR
+,22 ,var1 STR ( store 0x22 in var1 )
+,var1 LDR ( load var2, put value on stack )
 
-:label1
+@0100 ( store program reset after zero-page )
+
+:RESET ( --- )
+  BRK
+
+@c000 ( much further.. )
+
+:FRAME ( --- )
+  BRK
+
+@d000 ( further still.. )
+
+:ERROR ( --- )
+  BRK
+
+@FFFA ( vectors, last 3 shorts )
+
+.RESET
+.FRAME
+.ERROR

uxn.c

@@ -31,7 +31,7 @@ typedef struct {
 
 typedef struct {
 	Uint8 literal, status;
-	Uint16 counter;
+	Uint16 counter, vreset, vframe, verror;
 	Stack wst, rst;
 	Memory rom, ram;
 } Computer;
@@ -85,6 +85,8 @@ echom(Memory *m, Uint8 len, char *name)
 
 /* clang-format off */
 
+Uint8 mempoke8(Uint16 p) { return cpu.rom.dat[p+1] & 0xff; }
+Uint16 mempoke16(Uint16 p) { return (cpu.rom.dat[p] << 8) + (cpu.rom.dat[p+1] & 0xff); }
 void wspush(Uint8 b) { cpu.wst.dat[cpu.wst.ptr++] = b; }
 Uint8 wspop(void) { return cpu.wst.dat[--cpu.wst.ptr]; }
 void wspush16(Uint16 s) { 
@@ -120,7 +122,7 @@ void op_add() { wspush(wspop() + wspop()); }
 void op_sub() { wspush(wspop() - wspop()); }
 void op_mul() { wspush(wspop() * wspop()); }
 void op_div() { wspush(wspop() / wspop()); }
-void op_ldr() { wspush16(wspop16()); }
+void op_ldr() { wspush(cpu.ram.dat[wspop16()]); }
 void op_str() { cpu.ram.dat[wspop16()] = wspop(); }
 
 void (*ops[])(void) = {
@@ -134,8 +136,7 @@ Uint8 opr[][2] = {
 	{0,0}, {0,0}, {0,0}, {1,0}, {0,1}, {1,1}, {0,1}, {3,3},
 	{2,0}, {2,0}, {2,0}, {2,0}, {2,1}, {2,1}, {2,1}, {2,1},
 	{1,0}, {1,0}, {1,0}, {1,0}, {2,1}, {0,0}, {0,0}, {0,0},
-	{2,1}, {2,1}, {2,1}, {2,1}, {2,1}, {2,1}, {2,1}, {2,1},
-	{3,1}, {3,1}
+	{2,1}, {3,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}, {0,0}
 };
 
 /* clang-format on */
@@ -163,12 +164,6 @@ error(char *name)
 	return 0;
 }
 
-void
-load(FILE *f)
-{
-	fread(cpu.rom.dat, sizeof(cpu.rom.dat), 1, f);
-}
-
 int
 eval()
 {
@@ -195,8 +190,13 @@ eval()
 }
 
 void
-run(void)
+start(FILE *f)
 {
+	reset();
+	fread(cpu.rom.dat, sizeof(cpu.rom.dat), 1, f);
+	cpu.vreset = mempoke16(0xfffa);
+	cpu.vframe = mempoke16(0xfffc);
+	cpu.verror = mempoke16(0xfffe);
 	while(!(cpu.status & FLAG_HALT) && eval(cpu))
 		;
 	/* debug */
@@ -217,9 +217,7 @@ main(int argc, char *argv[])
 		return error("No input.");
 	if(!(f = fopen(argv[1], "rb")))
 		return error("Missing input.");
-	reset();
-	load(f);
-	run();
+	start(f);
 	/* print result */
 	echos(&cpu.wst, 0x40, "stack");
 	echom(&cpu.ram, 0x40, "ram");

uxnasm.c

@@ -178,7 +178,7 @@ findop(char *s)
 }
 
 int
-makelabel(char *id, Uint8 addr)
+makelabel(char *id, Uint16 addr)
 {
 	Label *l;
 	if(findlabel(id))
@@ -193,7 +193,8 @@ makelabel(char *id, Uint8 addr)
 int
 pass1(FILE *f)
 {
-	int skip = 0, addr = 0, vars = 0;
+	int skip = 0, vars = 0;
+	Uint16 addr = 0;
 	char w[64];
 	while(fscanf(f, "%s", w) == 1) {
 		if(iscomment(w, &skip)) continue;
@@ -205,9 +206,9 @@ pass1(FILE *f)
 		/* move addr ptr */
 		if(findop(w) || scmp(w, "BRK"))
 			addr += 1;
-		else if(w[0] == '@')
-			addr += 0;
-		else if(w[0] == ':')
+		else if(w[0] == '@') {
+			addr = shex(w + 1);
+		} else if(w[0] == ':')
 			addr += 0;
 		else if(w[0] == ';')
 			addr += 0;
@@ -264,5 +265,6 @@ main(int argc, char *argv[])
 		return error("Assembly", "Failed");
 	fwrite(p.data, sizeof(p.data), 1, fopen(argv[2], "wb"));
 	fclose(f);
+	printf("Assembled %s.\n", argv[2]);
 	return 0;
 }