it works again

Makefile

@@ -3,6 +3,7 @@ CFLAGS=-g -Wall -std=c99 -Iinc
 
 all:
 	$(CC) $(CFLAGS) src/*.c -o 6502
+	util/build
 
 clean:
 	rm 6502

inc/addressing_modes.h

@@ -7,8 +7,9 @@ typedef unsigned short(*addrmode_t)(cpu_t*);
 
 #define ADDRMODE(mode) unsigned short addrmode_##mode(cpu_t* cpu)
 
-ADDRMODE(none);
+ADDRMODE(implied);
 ADDRMODE(imm8);
 ADDRMODE(imm16);
+ADDRMODE(relative);
 
 #endif

inc/cpu.h

@@ -14,6 +14,8 @@
 #define SET_FLAG(state,flag)	(state)->regs.flags |= (flag)
 #define CLEAR_FLAG(state,flag)	(state)->regs.flags &= ~(flag);
 
+#define FLAG_IF(state,flag,condition) if(condition) { SET_FLAG(state,flag); } else { CLEAR_FLAG(state,flag); }
+
 typedef struct reg
 {
 	unsigned short pc;
@@ -69,4 +71,7 @@ void			cpu_mmap(cpu_t* cpu, mmapseg_t* segment);
 unsigned char	cpu_peek(cpu_t* cpu, unsigned short address);
 void			cpu_poke(cpu_t* cpu, unsigned short address, unsigned char val);
 
+unsigned short	cpu_peek_16(cpu_t* cpu, unsigned short address);
+void			cpu_poke_16(cpu_t* cpu, unsigned short address, unsigned short val);
+
 #endif

inc/instructions.h

@@ -8,5 +8,8 @@ typedef void(*ins_t)(cpu_t*, unsigned short);
 #define INS(name) void ins_##name(cpu_t* cpu, unsigned short param)
 
 INS(brk);
+INS(lda);
+INS(ldx);
+INS(rti);
 
 #endif

inc/opcodes.h

@@ -1,6 +1,8 @@
 #ifndef OPCODES_H
 #define OPCODES_H
 
+#define OP(i,a) (ins_##i), (addrmode_##a)
+
 extern void* opcodes[];
 
 #endif

src/addressing_modes.c

@@ -2,7 +2,7 @@
 #include <vm.h>
 #include <cpu.h>
 
-ADDRMODE(none)
+ADDRMODE(implied)
 {
 	return 0;
 }
@@ -16,3 +16,11 @@ ADDRMODE(imm16)
 {
 	return vm_next_16(cpu);
 }
+
+ADDRMODE(relative)
+{
+	signed char offset = (signed char)vm_next_8(cpu);
+	return cpu->regs.pc + offset;
+}
+
+

src/cpu.c

@@ -105,4 +105,17 @@ void cpu_poke(cpu_t* cpu, unsigned short address, unsigned char val)
 	cpu->mem[address] = val;
 }
 
+unsigned short cpu_peek_16(cpu_t* cpu, unsigned short address)
+{
+	unsigned char lsb = cpu_peek(cpu, address);
+	unsigned char msb = cpu_peek(cpu, address + 1);
+
+	return msb << 8 | lsb;
+}
+
+void cpu_poke_16(cpu_t* cpu, unsigned short address, unsigned short val)
+{
+	cpu_poke(cpu, address, val & 255);
+	cpu_poke(cpu, address + 1, val >> 8);
+}
 

src/instructions.c

@@ -5,3 +5,25 @@ INS(brk)
 {
 	cpu_brk(cpu);
 }
+
+INS(lda)
+{
+	cpu->regs.a = param & 255;
+
+	FLAG_IF(cpu, FZERO, cpu->regs.a == 0);
+	FLAG_IF(cpu, FNEG, cpu->regs.a & 128);
+}
+
+INS(ldx)
+{
+	cpu->regs.x = param & 255;
+
+	FLAG_IF(cpu, FZERO, cpu->regs.x == 0);
+	FLAG_IF(cpu, FNEG, cpu->regs.x & 128);
+}
+
+INS(rti)
+{
+	cpu->regs.flags = cpu_pop_8(cpu);
+	cpu->regs.pc = cpu_pop_16(cpu);
+}

src/opcodes.c

@@ -6,7 +6,7 @@
 void* opcodes[] = {
 
 	// 00
-	ins_brk, addrmode_none,
+	OP(brk, implied),
 	NULL, NULL,
 	NULL, NULL,
 	NULL, NULL,
@@ -86,7 +86,7 @@ void* opcodes[] = {
 	NULL, NULL,
 	NULL, NULL,
 	// 40
-	NULL, NULL,
+	OP(rti, implied),
 	NULL, NULL,
 	NULL, NULL,
 	NULL, NULL,
@@ -208,7 +208,7 @@ void* opcodes[] = {
 	// A0
 	NULL, NULL,
 	NULL, NULL,
-	NULL, NULL,
+	OP(ldx, imm8),
 	NULL, NULL,
 	// A4
 	NULL, NULL,
@@ -217,7 +217,7 @@ void* opcodes[] = {
 	NULL, NULL,
 	// A8
 	NULL, NULL,
-	NULL, NULL,
+	OP(lda, imm8),
 	NULL, NULL,
 	NULL, NULL,
 	// AC

util/test.asm

@@ -4,6 +4,9 @@
 	lda #$BE
 	ldx #$EF
 
+	hi:
+		jmp hi
+
 	nmi:
 		rti
 	reset: