terminei a cpu, mas ta errado em alguma parte e eu nao seiHEADmaster

1 files changed, 824 insertions, 273 deletions

diff --git a/CPU.c b/CPU.c
index a0fe581..5e82aab 100644
--- a/CPU.c
+++ b/CPU.c
@@ -6,347 +6,898 @@
 #include "CPU.h"
 #include "opcode_pc.h"
 
+#include <raylib.h>
+
+#define STACK 0x0100
+#define STACK_RESET 0xfd
+
 struct CPU create_cpu(){
-    struct CPU cpu = {
-        .register_a = 0,
-        .register_x = 0,
-        .register_y = 0,
-        .status = 0,
-        .pc = 0
-        };
-    return cpu;
+	struct CPU cpu = {
+		.register_a = 0,
+		.register_x = 0,
+		.register_y = 0,
+		.status = 0,
+		.pc = 0,
+		.sp = STACK_RESET
+	};
+	return cpu;
+}
+
+uint8_t stack_pop(struct CPU *cpu){
+	cpu->sp += 1;
+	uint8_t data = mem_read(cpu, (uint16_t)STACK | (uint16_t)cpu->sp);
+	return data;
+}
+
+void stack_push(struct CPU *cpu, uint8_t data){
+	uint16_t addr = (uint16_t)STACK | (uint16_t)cpu->sp;
+	mem_write(cpu, addr, data);
+	cpu->sp -= 1;
 }
 
-int array_size(uint8_t *program){
-    return sizeof(program) / sizeof(program[0]);
+void stack_push_u16(struct CPU *cpu, uint16_t data){
+	uint8_t hi = data >> 8;
+	uint8_t lo = data & 0xFF;
+	stack_push(cpu, hi);
+	stack_push(cpu, lo);
+}
+
+uint16_t stack_pop_u16(struct CPU *cpu){
+	uint16_t lo = (uint16_t)stack_pop(cpu);
+	uint16_t hi = (uint16_t)stack_pop(cpu);
+	uint16_t data = (hi << 8) | lo;
+	return data;
 }
 
 uint8_t mem_read(struct CPU *cpu, uint16_t addr){
-    return cpu->memory[addr];
+	return cpu->memory[addr];
 }
 
 void mem_write(struct CPU *cpu, uint16_t addr, uint8_t data){
-    cpu->memory[addr] = data;
+	cpu->memory[addr] = data;
 }
 
 uint16_t mem_read_u16(struct CPU *cpu, uint16_t pos){
-    //little-endian
-    uint16_t lo = (uint16_t)mem_read(cpu, pos);
-    uint16_t hi = (uint16_t)mem_read(cpu, pos+1);
-    return (hi<<8) | (lo);
+	//little-endian
+	uint16_t lo = (uint16_t)mem_read(cpu, pos);
+	uint16_t hi = (uint16_t)mem_read(cpu, pos+1);
+	return (hi<<8) | (lo);
 }
 
 void mem_write_u16(struct CPU *cpu, uint16_t pos, uint16_t data){
-    uint8_t hi = (uint8_t)(data>>8);
-    uint8_t lo = (uint8_t)(data & 0x00ff);
-    mem_write(cpu, pos, lo);
-    mem_write(cpu, pos+1, hi);
+	uint8_t hi = (uint8_t)(data>>8);
+	uint8_t lo = (uint8_t)(data & 0x00ff);
+	mem_write(cpu, pos, lo);
+	mem_write(cpu, pos+1, hi);
 }
-
+/*
 void load(struct CPU *cpu, uint8_t *program){
-    for(int i=0; i < array_size(program); ++i){
-        cpu->memory[0x8000+i] = program[i];
-    }
-    mem_write_u16(cpu, 0xfffc, 0x8000);
+	for(int i=0; i < array_size(program); ++i){
+		cpu->memory[0x8000+i] = program[i];
+	}
+	mem_write_u16(cpu, 0xfffc, 0x8000);
+}
+*/
+void load(struct CPU *cpu, uint8_t *program, int size_of_program){
+	for(int i=0; i < size_of_program; ++i){
+		cpu->memory[0x0600+i] = program[i];
+	}
+	mem_write_u16(cpu, 0xfffc, 0x0600);
 }
 
-void load_and_run(struct CPU *cpu, uint8_t *program){
-    load(cpu, program);
-    reset_cpu(cpu);
-    interpret(cpu);
+void load_and_run(struct CPU *cpu, uint8_t *program, int size_of_program){
+	load(cpu, program, size_of_program);
+	reset_cpu(cpu);
+	interpret(cpu);
 }
 
 void reset_cpu(struct CPU *cpu){
-    (*cpu).register_a = 0;
-    (*cpu).register_x = 0;
-    (*cpu).status = 0;
-    (*cpu).pc = mem_read_u16(cpu, 0xfffc);
+	(*cpu).register_a = 0;
+	(*cpu).register_x = 0;
+	(*cpu).status = 0;
+	(*cpu).pc = mem_read_u16(cpu, 0xfffc);
 }
 
 uint16_t get_operand_address(struct CPU *cpu, enum adressing_mode mode){
-    switch(mode){
-        case Immediate:
-            return cpu->pc;
-        case ZeroPage:
-            return (uint16_t)mem_read(cpu, cpu->pc);
-
-        case Absolute:
-            return mem_read_u16(cpu, cpu->pc);
-
-        case ZeroPage_X:
-            {
-            uint8_t pos = mem_read(cpu, cpu->pc);
-            uint16_t addr = (pos + cpu->register_x) % 0x100;
-            return addr;
-            }
-
-        case ZeroPage_Y:
-            {
-            uint8_t pos = mem_read(cpu, cpu->pc);
-            uint16_t addr = (pos + cpu->register_y) % 0x100;
-            return addr;
-            }
-
-        case Absolute_X:
-            {
-            uint16_t pos = mem_read_u16(cpu, cpu->pc);
-            uint16_t addr = (pos + (uint16_t)cpu->register_x) % 0x10000;
-            return addr;
-            }
-
-        case Absolute_Y:
-            {
-            uint16_t pos = mem_read_u16(cpu, cpu->pc);
-            uint16_t addr = (pos + (uint16_t)cpu->register_y) % 0x10000;
-            return addr;
-            }
-
-        case Indirect_X:
-            {
-            uint8_t pos = mem_read(cpu, cpu->pc);
-
-            uint8_t ptr = (pos + cpu->register_x) % 0x100;
-            uint8_t lo  = mem_read(cpu, (uint16_t)ptr);
-            uint8_t hi  = mem_read(cpu, (uint16_t)((ptr+1) % 0x100));
-            return ((uint16_t)hi << 8) | ((uint16_t)lo);
-            }
-        
-        case Indirect_Y:
-            {
-            uint8_t pos = mem_read(cpu, cpu->pc);
-
-            uint8_t lo = mem_read(cpu, (uint16_t)pos);
-            uint8_t hi = mem_read(cpu, (uint16_t)((pos+1) % 0x100));
-            uint16_t deref_pos = ((uint16_t)hi << 8) | (uint16_t)lo;
-            uint16_t deref = (deref_pos + (uint16_t)cpu->register_y) % 0x10000;
-            return deref;
-            }
-
-        case NoneAddressing:
-            exit(1);
-            break;
-    }
+	switch(mode){
+		case Immediate:
+			return cpu->pc;
+		case ZeroPage:
+			return (uint16_t)mem_read(cpu, cpu->pc);
+
+		case Absolute:
+			return mem_read_u16(cpu, cpu->pc);
+
+		case ZeroPage_X:
+			{
+				uint8_t pos = mem_read(cpu, cpu->pc);
+				uint16_t addr = (pos + cpu->register_x) % 0x100;
+				return addr;
+			}
+
+		case ZeroPage_Y:
+			{
+				uint8_t pos = mem_read(cpu, cpu->pc);
+				uint16_t addr = (pos + cpu->register_y) % 0x100;
+				return addr;
+			}
+
+		case Absolute_X:
+			{
+				uint16_t pos = mem_read_u16(cpu, cpu->pc);
+				uint16_t addr = (pos + (uint16_t)cpu->register_x) % 0x10000;
+				return addr;
+			}
+
+		case Absolute_Y:
+			{
+				uint16_t pos = mem_read_u16(cpu, cpu->pc);
+				uint16_t addr = (pos + (uint16_t)cpu->register_y) % 0x10000;
+				return addr;
+			}
+
+		case Indirect_X:
+			{
+				uint8_t pos = mem_read(cpu, cpu->pc);
+
+				uint8_t ptr = (pos + cpu->register_x) % 0x100;
+				uint8_t lo  = mem_read(cpu, (uint16_t)ptr);
+				uint8_t hi  = mem_read(cpu, (uint16_t)((ptr+1) % 0x100));
+				return ((uint16_t)hi << 8) | ((uint16_t)lo);
+			}
+
+		case Indirect_Y:
+			{
+				uint8_t pos = mem_read(cpu, cpu->pc);
+
+				uint8_t lo = mem_read(cpu, (uint16_t)pos);
+				uint8_t hi = mem_read(cpu, (uint16_t)((pos+1) % 0x100));
+				uint16_t deref_pos = ((uint16_t)hi << 8) | (uint16_t)lo;
+				uint16_t deref = (deref_pos + (uint16_t)cpu->register_y) % 0x10000;
+				return deref;
+			}
+
+		case NoneAddressing:
+			exit(1);
+			break;
+	}
 }
 
 void update_zero_and_negative_flags(struct CPU *cpu, uint8_t result){
-    if(result == 0)
-        enable_flag(cpu, ZERO);//cpu->status |= 0b00000010;
-    else
-        disable_flag(cpu, ZERO);//cpu->status &= 0b11111101;
-
-    if((result & 0b10000000) != 0)
-        cpu->status |= 0b10000000;
-    else
-        cpu->status &= 0b01111111;
+	if(result == 0)
+		enable_flag(cpu, ZERO);//cpu->status |= 0b00000010;
+	else
+		disable_flag(cpu, ZERO);//cpu->status &= 0b11111101;
+
+	if((result & 0b10000000) != 0)
+		cpu->status |= 0b10000000;
+	else
+		cpu->status &= 0b01111111;
 }
 
 void lda(struct CPU *cpu, enum adressing_mode mode/*uint8_t value*/){
-    uint16_t addr = get_operand_address(cpu, mode);
-    uint8_t value = mem_read(cpu, addr);
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+
+	cpu->register_a = value;
+	update_zero_and_negative_flags(cpu, cpu->register_a);
+	// cpu->register_a = value;
+	// update_zero_and_negative_flags(cpu, cpu->register_a);
+}
+
+void ldx(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+
+	cpu->register_x = value;
+	update_zero_and_negative_flags(cpu, cpu->register_x);
+}
+
+void ldy(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+
+	cpu->register_y = value;
+	update_zero_and_negative_flags(cpu, cpu->register_y);
+}
+
+void dec(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+
+	uint8_t data = value - 1;
+	mem_write(cpu, addr, data);
+	update_zero_and_negative_flags(cpu, data);
+}
+
+void eor(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
 
-    cpu->register_a = value;
-    update_zero_and_negative_flags(cpu, cpu->register_a);
-    // cpu->register_a = value;
-    // update_zero_and_negative_flags(cpu, cpu->register_a);
+	cpu->register_a ^= value;
+	update_zero_and_negative_flags(cpu, cpu->register_a);
+}
+
+void inc(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+
+	uint8_t data = value + 1;
+	mem_write(cpu, addr, data);
+	update_zero_and_negative_flags(cpu, data);
 }
 
 void sta(struct CPU *cpu, enum adressing_mode mode){
-    uint16_t addr = get_operand_address(cpu, mode);
-    mem_write(cpu, addr, cpu->register_a);
+	uint16_t addr = get_operand_address(cpu, mode);
+	mem_write(cpu, addr, cpu->register_a);
+}
+
+void stx(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	mem_write(cpu, addr, cpu->register_x);
+}
+
+void sty(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	mem_write(cpu, addr, cpu->register_y);
 }
 
 void and(struct CPU *cpu, enum adressing_mode mode){
-    uint16_t addr = get_operand_address(cpu, mode);
-    uint8_t value = mem_read(cpu, addr);
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
 
-    cpu->register_a &= value;
-    update_zero_and_negative_flags(cpu, cpu->register_a);
+	cpu->register_a &= value;
+	update_zero_and_negative_flags(cpu, cpu->register_a);
 }
 
 void enable_flag(struct CPU *cpu, uint8_t flag){
-    cpu->status |= flag;
+	cpu->status |= flag;
 }
 
 void disable_flag(struct CPU *cpu, uint8_t flag){
-    cpu->status &= ~flag;
+	cpu->status &= ~flag;
 }
 
 int test_flag(struct CPU *cpu, uint8_t flag){
-    return (flag & cpu->status) > 0;
+	return (flag & cpu->status) > 0;
 }
 
 void branch(struct CPU *cpu, bool cond){
-    if(cond){
-        int8_t jump = mem_read(cpu, cpu->pc);
-        cpu->pc = (cpu->pc + jump + 1) % 0x10000;
-    }
+	if(cond){
+		int8_t jump = mem_read(cpu, cpu->pc);
+		cpu->pc = (cpu->pc + jump + 1) % 0x10000;
+	}
 }
 
 void asl(struct CPU *cpu, enum adressing_mode mode){
-    uint16_t addr = get_operand_address(cpu, mode);
-    uint8_t value = mem_read(cpu, addr);
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
 
-    if(value >> 7 == 1) enable_flag(cpu, CARRY);
-    else disable_flag(cpu, CARRY);
+	if(value >> 7 == 1) enable_flag(cpu, CARRY);
+	else disable_flag(cpu, CARRY);
 
-    value = value << 1;
-    mem_write(cpu, addr, value);
-    update_zero_and_negative_flags(cpu, value);
+	value = value << 1;
+	mem_write(cpu, addr, value);
+	update_zero_and_negative_flags(cpu, value);
 }
 
 void compare(struct CPU *cpu, enum adressing_mode mode, uint8_t comp_val){
-    uint16_t addr = get_operand_address(cpu, mode);
-    uint8_t value = mem_read(cpu, addr);
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
 
 
-    if(comp_val >= value){
-        enable_flag(cpu, CARRY);
-    }else{
-        disable_flag(cpu, CARRY);
-    }
+	if(comp_val >= value){
+		enable_flag(cpu, CARRY);
+	}else{
+		disable_flag(cpu, CARRY);
+	}
 
-    update_zero_and_negative_flags(cpu, (comp_val - value));
+	update_zero_and_negative_flags(cpu, (comp_val - value));
+}
+
+void lsr(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t data = mem_read(cpu, addr);
+	if(data & 1){
+		enable_flag(cpu, CARRY);
+	}else{
+		disable_flag(cpu, CARRY);
+	}
+	data = data >> 1;
+	mem_write(cpu, addr, data);	
+	update_zero_and_negative_flags(cpu, data);
+}
+
+void ora(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+
+	cpu->register_a |= value;
+	update_zero_and_negative_flags(cpu, cpu->register_a);
+}
+
+void rol(struct CPU *cpu, enum adressing_mode mode){
+	if(mode == NoneAddressing){
+		int c = test_flag(cpu, CARRY);
+		uint8_t value = cpu->register_a;
+		if((value >> 7) == 1){
+			enable_flag(cpu, CARRY);
+		}else{
+			disable_flag(cpu, CARRY);
+		}
+
+		value = value << 1;
+		if(c == 1){
+			value |= 1;
+		}else{
+		}
+		cpu->register_a = value;
+		update_zero_and_negative_flags(cpu, cpu->register_a);
+	}else{
+		int c = test_flag(cpu, CARRY);
+		uint16_t addr = get_operand_address(cpu, mode);
+		uint8_t value = mem_read(cpu, addr);
+		if((value >> 7) == 1){
+			enable_flag(cpu, CARRY);
+		}else{
+			disable_flag(cpu, CARRY);
+		}
+		
+		value = value << 1;
+		if(c == 1){
+			value |= 1;
+		}else{
+		}
+		mem_write(cpu, addr, value);
+		update_zero_and_negative_flags(cpu, value);
+	}
+}
+
+void ror(struct CPU *cpu, enum adressing_mode mode){
+	if(mode == NoneAddressing){
+		int c = test_flag(cpu, CARRY);
+		uint8_t data = cpu->register_a;
+		if((data & 1) == 1){
+			enable_flag(cpu, CARRY);
+		}else{
+			disable_flag(cpu, CARRY);
+		}
+
+		data = data >> 1;
+		if(c == 1){
+			data |= 0b10000000;
+		}else{
+		}
+
+		cpu->register_a = data;
+		update_zero_and_negative_flags(cpu, cpu->register_a);
+	}else{
+		int c = test_flag(cpu, CARRY);
+		uint16_t addr = get_operand_address(cpu, mode);
+		uint8_t data = mem_read(cpu, addr);
+		if((data & 1) == 1){
+			enable_flag(cpu, CARRY);
+		}else{
+			disable_flag(cpu, CARRY);
+		}
+
+		data = data >> 1;
+		if(c == 1){
+			data |= 0b10000000;
+		}else{
+		}
+
+		mem_write(cpu, addr, data);
+		update_zero_and_negative_flags(cpu, data);
+	}
+}
+
+void adc(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+	uint8_t ra = cpu->register_a;
+	//sum = value + ra + CARRY;
+	uint16_t sum;
+	sum = (uint16_t)value + (uint16_t)ra;
+	if(test_flag(cpu, CARRY) == 1){
+		sum += 1;
+	}else{
+	}
+
+	bool new_carry = (sum > 0xFF); // will set carry flag in overflow too
+	if(new_carry == 1) enable_flag(cpu, CARRY);
+	else disable_flag(cpu, CARRY);
+
+	sum &= 0xFF; // sum & 0b11111111
+	uint8_t res = (uint8_t)sum;
+	// ver se os sinais mudaram
+	// ra, value, res
+	// ra ^ res -> bit 7 flipou?
+	// value ^ res -> bit 7 fliplou?
+	// 1 1 0 - 1
+	// 0 0 1 - 1
+	// 0 0 0 - 0
+	// 1 1 1 - 0
+	if( (value ^ res) & (ra ^ res) & 0x80 ){
+		enable_flag(cpu, OVERFLOW);
+	}else{
+		disable_flag(cpu, OVERFLOW);
+	}
+
+	cpu->register_a = res;
+	update_zero_and_negative_flags(cpu, cpu->register_a);
+}
+
+void sbc(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+	value = ~value + 1;
+	uint8_t ra = cpu->register_a;
+	//sum = value + ra + CARRY;
+	uint16_t sum;
+	sum = (uint16_t)value + (uint16_t)ra;
+	if(test_flag(cpu, CARRY) == 1){
+		sum += 1;
+	}else{
+	}
+
+	bool new_carry = (sum > 0xFF); // will set carry flag in overflow too
+	if(new_carry == 1) enable_flag(cpu, CARRY);
+	else disable_flag(cpu, CARRY);
+
+	sum &= 0xFF; // sum & 0b11111111
+	uint8_t res = (uint8_t)sum;
+	// ver se os sinais mudaram
+	// ra, value, res
+	// ra ^ res -> bit 7 flipou?
+	// value ^ res -> bit 7 fliplou?
+	// 1 1 0 - 1
+	// 0 0 1 - 1
+	// 0 0 0 - 0
+	// 1 1 1 - 0
+	if( (value ^ res) & (ra ^ res) & 0x80 ){
+		enable_flag(cpu, OVERFLOW);
+	}else{
+		disable_flag(cpu, OVERFLOW);
+	}
+
+	cpu->register_a = res;
+	update_zero_and_negative_flags(cpu, cpu->register_a);
+
+}
+void bit(struct CPU *cpu, enum adressing_mode mode){
+	uint16_t addr = get_operand_address(cpu, mode);
+	uint8_t value = mem_read(cpu, addr);
+
+	value &= cpu->register_a;
+	if(value == 0){
+		enable_flag(cpu, ZERO);
+	}else{
+		disable_flag(cpu, ZERO);
+	}
+
+	if((value & 0b01000000) > 0){
+		enable_flag(cpu, OVERFLOW);
+	}else{
+		disable_flag(cpu, OVERFLOW);
+	}
+
+	if((value & 0b10000000) > 0){
+		enable_flag(cpu, NEGATIV);
+	}else{
+		disable_flag(cpu, NEGATIV);
+	}
 }
 
 void interpret(struct CPU *cpu){
 
-    while(1){
-        uint8_t opcode = mem_read(cpu, cpu->pc);
-        cpu->pc += 1;
-
-        switch(OPCODE[opcode].instruction){
-            case BRK:
-                return;
-            case TAX:
-                cpu->register_x = cpu->register_a;
-                update_zero_and_negative_flags(cpu, cpu->register_x);
-                break;
-            case LDA:
-                lda(cpu, OPCODE[opcode].mode);
-                cpu->pc += OPCODE[opcode].bytes - 1;
-                break;
-            case STA:
-                sta(cpu, OPCODE[opcode].mode);
-                cpu->pc += OPCODE[opcode].bytes - 1;
-                break;
-            case INX:
-                cpu->register_x++;
-                update_zero_and_negative_flags(cpu, cpu->register_x);
-                break;
-            case AND:
-                and(cpu, OPCODE[opcode].mode);
-                cpu->pc += OPCODE[opcode].bytes - 1;
-                break;
-            case ASL:
-                if(OPCODE[opcode].mode == NoneAddressing){
-                    uint8_t value = cpu->register_a;
-                    if(value >> 7 == 1) enable_flag(cpu, CARRY);
-                    else disable_flag(cpu, CARRY);
-                    cpu->register_a = value << 1;
-                    update_zero_and_negative_flags(cpu, cpu->register_a);
-                }else{
-                    asl(cpu, OPCODE[opcode].mode);
-                }
-                cpu->pc += OPCODE[opcode].bytes - 1;
-                break;
-            case BCC:
-                branch(cpu, !test_flag(cpu, CARRY));
-                break;
-            case BCS:
-                branch(cpu, test_flag(cpu, CARRY));
-                break;
-            case BEQ:
-                branch(cpu, test_flag(cpu, ZERO));
-                break;
-            case BMI:
-                branch(cpu, test_flag(cpu, NEGATIV));
-                break;
-            case BNE:
-                branch(cpu, !test_flag(cpu, ZERO));
-                break;
-            case BPL:
-                branch(cpu, !test_flag(cpu, NEGATIV));
-                break;
-            case BVC:
-                branch(cpu, !test_flag(cpu, OVERFLOW));
-                break;
-            case BVS:
-                branch(cpu, test_flag(cpu, OVERFLOW));
-                break;
+	//while(1){
+	{
+		uint8_t opcode = mem_read(cpu, cpu->pc);
+	//	printf("opcode %x\n", opcode);
+	//	printf("pc %x\n", cpu->pc);
+		cpu->pc += 1;
+		uint16_t save_pc = cpu->pc;
+
+		switch(OPCODE[opcode].instruction){
+			case BRK:
+				return;
+			case TAX:
+				cpu->register_x = cpu->register_a;
+				update_zero_and_negative_flags(cpu, cpu->register_x);
+				break;
+			case LDA:
+				lda(cpu, OPCODE[opcode].mode);
+				cpu->pc += OPCODE[opcode].bytes - 1;
+				break;
+			case STA:
+				sta(cpu, OPCODE[opcode].mode);
+				cpu->pc += OPCODE[opcode].bytes - 1;
+				break;
+			case INX:
+				cpu->register_x++;
+				update_zero_and_negative_flags(cpu, cpu->register_x);
+				break;
+			case AND:
+				and(cpu, OPCODE[opcode].mode);
+				cpu->pc += OPCODE[opcode].bytes - 1;
+				break;
+			case ASL:
+				if(OPCODE[opcode].mode == NoneAddressing){
+					uint8_t value = cpu->register_a;
+					if(value >> 7 == 1) enable_flag(cpu, CARRY);
+					else disable_flag(cpu, CARRY);
+					cpu->register_a = value << 1;
+					update_zero_and_negative_flags(cpu, cpu->register_a);
+				}else{
+					asl(cpu, OPCODE[opcode].mode);
+				}
+				cpu->pc += OPCODE[opcode].bytes - 1;
+				break;
+			case BCC:
+				branch(cpu, !test_flag(cpu, CARRY));
+				break;
+			case BCS:
+				branch(cpu, test_flag(cpu, CARRY));
+				break;
+			case BEQ:
+				branch(cpu, test_flag(cpu, ZERO));
+				break;
+			case BMI:
+				branch(cpu, test_flag(cpu, NEGATIV));
+				break;
+			case BNE:
+				branch(cpu, !test_flag(cpu, ZERO));
+				break;
+			case BPL:
+				branch(cpu, !test_flag(cpu, NEGATIV));
+				break;
+			case BVC:
+				branch(cpu, !test_flag(cpu, OVERFLOW));
+				break;
+			case BVS:
+				branch(cpu, test_flag(cpu, OVERFLOW));
+				break;
 			case CLC:
-                disable_flag(cpu, CARRY);
-                break;
-            case CLD:
-                disable_flag(cpu, DECIMAL_MODE);
-                break;
-            case CLI:
-                disable_flag(cpu, INTERRUPT_DISABLE);
-                break;
-            case CLV:
-                disable_flag(cpu, OVERFLOW);
-                break;
-            case CMP:
-                compare(cpu, OPCODE[opcode].mode, cpu->register_a);
-                break;
-            case CPX:
-                compare(cpu, OPCODE[opcode].mode, cpu->register_x);
-                break;
-            case CPY:
-                compare(cpu, OPCODE[opcode].mode, cpu->register_y);
-                break;
-            default:
-                break;
-        }
-    }
-
-    return;
+				disable_flag(cpu, CARRY);
+				break;
+			case CLD:
+				disable_flag(cpu, DECIMAL_MODE);
+				break;
+			case CLI:
+				disable_flag(cpu, INTERRUPT_DISABLE);
+				break;
+			case CLV:
+				disable_flag(cpu, OVERFLOW);
+				break;
+			case CMP:
+				compare(cpu, OPCODE[opcode].mode, cpu->register_a);
+				break;
+			case CPX:
+				compare(cpu, OPCODE[opcode].mode, cpu->register_x);
+				break;
+			case CPY:
+				compare(cpu, OPCODE[opcode].mode, cpu->register_y);
+				break;
+			case DEC:
+				dec(cpu, OPCODE[opcode].mode);
+				break;
+			case DEX:
+				cpu->register_x -= 1;
+				update_zero_and_negative_flags(cpu, cpu->register_x);
+				break;
+			case DEY:
+				cpu->register_y -= 1;
+				update_zero_and_negative_flags(cpu, cpu->register_y);
+			case EOR:
+				eor(cpu, OPCODE[opcode].mode);
+				break;
+			case INC:
+				inc(cpu, OPCODE[opcode].mode);
+				break;
+			case INY:
+				cpu->register_y++;
+				update_zero_and_negative_flags(cpu, cpu->register_y);
+				break;
+			case JMP:
+				if(OPCODE[opcode].mode == Absolute){
+					uint16_t addr = get_operand_address(cpu, Absolute);
+					cpu->pc = addr;
+				}else{
+					/*Indirect -> JMP is the only 6502 instruction to support indirection.*/
+					uint16_t addr = mem_read_u16(cpu, cpu->pc);
+
+					uint16_t indirect_ref;
+					if((addr & 0x00FF) == 0x00FF){
+						uint8_t lo = mem_read(cpu, addr);
+						uint8_t hi = mem_read(cpu, addr & 0x00FF);
+						indirect_ref = ((uint16_t)hi << 8) | ((uint16_t)lo);
+					}else{
+						indirect_ref = mem_read_u16(cpu, addr);
+					}
+
+					cpu->pc = indirect_ref;
+				}
+				break;
+			case JSR: // + 2 -> JSR uses 3 bytes, but 1 is already added
+				stack_push_u16(cpu, cpu->pc + 2 - 1);
+				uint16_t new_addr = mem_read_u16(cpu, cpu->pc);
+				cpu->pc = new_addr;
+
+				break;
+			case LDX:
+				ldx(cpu, OPCODE[opcode].mode);
+				break;
+			case LDY:
+				ldy(cpu, OPCODE[opcode].mode);
+				break;
+			case LSR:
+				if(OPCODE[opcode].mode == NoneAddressing){
+					uint8_t data = cpu->register_a;
+					if(data & 1){
+						enable_flag(cpu, CARRY);
+					}else{
+						disable_flag(cpu, CARRY);
+					}
+					data = data >> 1;
+					cpu->register_a = data;
+					update_zero_and_negative_flags(cpu, cpu->register_a);
+				}else{
+					lsr(cpu, OPCODE[opcode].mode);
+				}
+				break;
+			case NOP:
+				break;
+			case ORA:
+				ora(cpu, OPCODE[opcode].mode);
+				break;
+			case PHA:
+				stack_push(cpu, cpu->register_a);
+				break;
+			case PHP:
+				stack_push(cpu, cpu->status | BREAK | BREAK2);
+				break;
+			case PLA:
+				cpu->register_a = stack_pop(cpu);
+				update_zero_and_negative_flags(cpu, cpu->register_a);
+				break;
+			case PLP:
+				{
+				uint8_t flags_data = stack_pop(cpu);
+				printf("flags pulled: %x\n", flags_data);
+				flags_data &= (~BREAK);
+				flags_data |= BREAK2;
+				printf("flags saved in status: %x\n", flags_data);
+				cpu->status = flags_data;
+				}
+				break;
+			case ROL:
+				rol(cpu, OPCODE[opcode].mode);
+				break;
+			case ROR:
+				ror(cpu, OPCODE[opcode].mode);
+				break;
+			case ADC:
+				adc(cpu, OPCODE[opcode].mode);
+				break;
+			case RTI:
+				cpu->status = stack_pop(cpu);
+				cpu->status &= ~BREAK;
+				cpu->status |= BREAK2;
+				cpu->pc = stack_pop_u16(cpu);
+				break;
+			case RTS:
+				cpu->pc = stack_pop_u16(cpu) + 1;
+				break;
+			case SBC:
+				sbc(cpu, OPCODE[opcode].mode);
+				break;
+			case SEC:
+				enable_flag(cpu, CARRY);
+				break;
+			case SED:
+				enable_flag(cpu, DECIMAL_MODE);
+				break;
+			case SEI:
+				enable_flag(cpu, INTERRUPT_DISABLE);
+				break;
+			case TAY:
+				cpu->register_y = cpu->register_a;
+				update_zero_and_negative_flags(cpu, cpu->register_y);
+				break;
+			case TSX:
+				cpu->register_x = cpu->sp;
+				update_zero_and_negative_flags(cpu, cpu->register_x);
+				break;
+			case TXA:
+				cpu->register_a = cpu->register_x;
+				update_zero_and_negative_flags(cpu, cpu->register_a);
+				break;
+			case TXS:
+				cpu->sp = cpu->register_x;
+				break;
+			case TYA:
+				cpu->register_a = cpu->register_y;
+				update_zero_and_negative_flags(cpu, cpu->register_a);
+				break;
+			case BIT:
+				bit(cpu, OPCODE[opcode].mode);
+				break;
+			default:
+				break;
+		}
+
+		if(save_pc == cpu->pc){
+			cpu->pc += OPCODE[opcode].bytes - 1;
+		}
+	}
+
+	return;
+}
+
+int test_operands(){
+	init_opcode_pc();
+
+	printf("test_0xa9_lda_immediate_load_data: ");
+	struct CPU cpu_1 = create_cpu();
+	uint8_t program_1[] = {0xa9, 0x05, 0x00};
+	load_and_run(&cpu_1, program_1, sizeof(program_1)/sizeof(program_1[0]));
+	assert(cpu_1.register_a == 0x05);
+	assert((cpu_1.status & 0b00000010) == 0b00);
+	assert((cpu_1.status & 0b10000000) == 0);
+	printf("PASSED\n");
+
+	printf("test_0xa9_lda_zero_flag: ");
+	struct CPU cpu_2 = create_cpu();
+	uint8_t program_2[] = {0xa9, 0x00, 0x00};
+	load_and_run(&cpu_2, program_2, sizeof(program_2)/sizeof(program_2[0]));
+	assert((cpu_2.status & 0b00000010) == 0b00000010);
+	printf("PASSED\n");
+
+	printf("text_0xaa_tax_move_a_to_x: ");
+	struct CPU cpu_3 = create_cpu();
+	uint8_t program_3[] = {0xa9, 10, 0xaa, 0x00};
+	load_and_run(&cpu_3, program_3, sizeof(program_3)/sizeof(program_3[0]));
+	assert(cpu_3.register_x == 10);
+	printf("PASSED\n");
+
+	printf("test_5_ops_working_together: ");
+	struct CPU cpu_4 = create_cpu();
+	uint8_t program_4[] = {0xa9, 0xc0, 0xaa, 0xe8, 0x00};
+	load_and_run(&cpu_4, program_4, sizeof(program_4)/sizeof(program_4[0]));
+	assert(cpu_4.register_x == 0xC1);
+	printf("PASSED\n");
+
+	printf("test_inx_overflow: ");
+	struct CPU cpu_5 = create_cpu();
+	uint8_t program_5[] = {0xa9, 0xff, 0xaa, 0xe8, 0xe8, 0x00};
+	load_and_run(&cpu_5, program_5, sizeof(program_5)/sizeof(program_5[0]));
+	assert(cpu_5.register_x == 1);
+	printf("PASSED\n");
+
+	printf("test_lda_from_memory: ");
+	struct CPU cpu_6 = create_cpu();
+	mem_write(&cpu_6, 0x10, 0x55);
+	uint8_t program_6[] = {0xa5, 0x10, 0x00};
+	load_and_run(&cpu_6, program_6, sizeof(program_6)/sizeof(program_6[0]));
+	assert(cpu_6.register_a == 0x55);
+	printf("PASSED\n");
+
+	printf("test_adc: ");
+	struct CPU cpu_7 = create_cpu();
+	uint8_t program_7[] = {0xa9, 64, 0x69, 64, 0x00};
+	load_and_run(&cpu_7, program_7, sizeof(program_7)/sizeof(program_7[0]));
+	assert(cpu_7.register_a == 128);
+	assert(test_flag(&cpu_7, OVERFLOW) == 1);
+	printf("PASSED\n");
+	
+	printf("test_sbc: ");
+	struct CPU cpu_8 = create_cpu();
+	uint8_t program_8[] = {0xa9, 0b10000000, 0xe9, 31, 0x00};
+	load_and_run(&cpu_8, program_8, sizeof(program_8)/sizeof(program_8[0]));
+	assert(cpu_8.register_a == 128-31);
+	assert(test_flag(&cpu_8, OVERFLOW) == 1);
+	printf("PASSED\n");
+
+	printf("test_sec: ");
+	struct CPU cpu_9 = create_cpu();
+	uint8_t program_9[] = {0xa9, 10, 0x38, 0xa9, 11, 0xa9, 12, 0x00};
+	load_and_run(&cpu_9, program_9, sizeof(program_9)/sizeof(program_9[0]));
+	assert(test_flag(&cpu_9, CARRY) == 1);
+	assert(cpu_9.register_a == 12);
+	printf("PASSED\n");
+	
+	return 0;
 }
 
 int main(){
-    init_opcode_pc();
-
-    printf("test_0xa9_lda_immediate_load_data: ");
-    struct CPU cpu_1 = create_cpu();
-    uint8_t program_1[] = {0xa9, 0x05, 0x00};
-    load_and_run(&cpu_1, program_1);
-    assert(cpu_1.register_a == 0x05);
-    assert((cpu_1.status & 0b00000010) == 0b00);
-    assert((cpu_1.status & 0b10000000) == 0);
-    printf("PASSED\n");
-
-    printf("test_0xa9_lda_zero_flag: ");
-    struct CPU cpu_2 = create_cpu();
-    uint8_t program_2[] = {0xa9, 0x00, 0x00};
-    load_and_run(&cpu_2, program_2);
-    assert((cpu_2.status & 0b00000010) == 0b00000010);
-    printf("PASSED\n");
-
-    printf("text_0xaa_tax_move_a_to_x: ");
-    struct CPU cpu_3 = create_cpu();
-    uint8_t program_3[] = {0xa9, 10, 0xaa, 0x00};
-    load_and_run(&cpu_3, program_3);
-    assert(cpu_3.register_x == 10);
-    printf("PASSED\n");
-
-    printf("test_5_ops_working_together: ");
-    struct CPU cpu_4 = create_cpu();
-    uint8_t program_4[] = {0xa9, 0xc0, 0xaa, 0xe8, 0x00};
-    load_and_run(&cpu_4, program_4);
-    assert(cpu_4.register_x == 0xC1);
-    printf("PASSED\n");
-
-    printf("test_inx_overflow: ");
-    struct CPU cpu_5 = create_cpu();
-    uint8_t program_5[] = {0xa9, 0xff, 0xaa, 0xe8, 0xe8, 0x00};
-    load_and_run(&cpu_5, program_5);
-    assert(cpu_5.register_x == 1);
-    printf("PASSED\n");
-
-    printf("test_lda_from_memory: ");
-    struct CPU cpu_6 = create_cpu();
-    mem_write(&cpu_6, 0x10, 0x55);
-    uint8_t program_6[] = {0xa5, 0x10, 0x00};
-    load_and_run(&cpu_6, program_6);
-    assert(cpu_6.register_a == 0x55);
-    printf("PASSED\n");
+	//test_operands();
+	init_opcode_pc();
+	
+	struct CPU cpu = create_cpu();
+	uint8_t program[] = {
+		0x20, 0x06, 0x06, 0x20, 0x38, 0x06, 0x20, 0x0d, 0x06, 0x20, 0x2a, 0x06, 0x60, 0xa9, 0x02, 0x85,
+		0x02, 0xa9, 0x04, 0x85, 0x03, 0xa9, 0x11, 0x85, 0x10, 0xa9, 0x10, 0x85, 0x12, 0xa9, 0x0f, 0x85,
+		0x14, 0xa9, 0x04, 0x85, 0x11, 0x85, 0x13, 0x85, 0x15, 0x60, 0xa5, 0xfe, 0x85, 0x00, 0xa5, 0xfe,
+		0x29, 0x03, 0x18, 0x69, 0x02, 0x85, 0x01, 0x60, 0x20, 0x4d, 0x06, 0x20, 0x8d, 0x06, 0x20, 0xc3,
+		0x06, 0x20, 0x19, 0x07, 0x20, 0x20, 0x07, 0x20, 0x2d, 0x07, 0x4c, 0x38, 0x06, 0xa5, 0xff, 0xc9,
+		0x77, 0xf0, 0x0d, 0xc9, 0x64, 0xf0, 0x14, 0xc9, 0x73, 0xf0, 0x1b, 0xc9, 0x61, 0xf0, 0x22, 0x60,
+		0xa9, 0x04, 0x24, 0x02, 0xd0, 0x26, 0xa9, 0x01, 0x85, 0x02, 0x60, 0xa9, 0x08, 0x24, 0x02, 0xd0,
+		0x1b, 0xa9, 0x02, 0x85, 0x02, 0x60, 0xa9, 0x01, 0x24, 0x02, 0xd0, 0x10, 0xa9, 0x04, 0x85, 0x02,
+		0x60, 0xa9, 0x02, 0x24, 0x02, 0xd0, 0x05, 0xa9, 0x08, 0x85, 0x02, 0x60, 0x60, 0x20, 0x94, 0x06,
+		0x20, 0xa8, 0x06, 0x60, 0xa5, 0x00, 0xc5, 0x10, 0xd0, 0x0d, 0xa5, 0x01, 0xc5, 0x11, 0xd0, 0x07,
+		0xe6, 0x03, 0xe6, 0x03, 0x20, 0x2a, 0x06, 0x60, 0xa2, 0x02, 0xb5, 0x10, 0xc5, 0x10, 0xd0, 0x06,
+		0xb5, 0x11, 0xc5, 0x11, 0xf0, 0x09, 0xe8, 0xe8, 0xe4, 0x03, 0xf0, 0x06, 0x4c, 0xaa, 0x06, 0x4c,
+		0x35, 0x07, 0x60, 0xa6, 0x03, 0xca, 0x8a, 0xb5, 0x10, 0x95, 0x12, 0xca, 0x10, 0xf9, 0xa5, 0x02,
+		0x4a, 0xb0, 0x09, 0x4a, 0xb0, 0x19, 0x4a, 0xb0, 0x1f, 0x4a, 0xb0, 0x2f, 0xa5, 0x10, 0x38, 0xe9,
+		0x20, 0x85, 0x10, 0x90, 0x01, 0x60, 0xc6, 0x11, 0xa9, 0x01, 0xc5, 0x11, 0xf0, 0x28, 0x60, 0xe6,
+		0x10, 0xa9, 0x1f, 0x24, 0x10, 0xf0, 0x1f, 0x60, 0xa5, 0x10, 0x18, 0x69, 0x20, 0x85, 0x10, 0xb0,
+		0x01, 0x60, 0xe6, 0x11, 0xa9, 0x06, 0xc5, 0x11, 0xf0, 0x0c, 0x60, 0xc6, 0x10, 0xa5, 0x10, 0x29,
+		0x1f, 0xc9, 0x1f, 0xf0, 0x01, 0x60, 0x4c, 0x35, 0x07, 0xa0, 0x00, 0xa5, 0xfe, 0x91, 0x00, 0x60,
+		0xa6, 0x03, 0xa9, 0x00, 0x81, 0x10, 0xa2, 0x00, 0xa9, 0x01, 0x81, 0x10, 0x60, 0xa2, 0x00, 0xea,
+		0xea, 0xca, 0xd0, 0xfb, 0x60
+	};
+
+	int sW, sH;
+	sW = sH = 320;
+	InitWindow(sW, sH, "snake");
+	load(&cpu, program, sizeof(program)/sizeof(program[0]));
+	reset_cpu(&cpu);
+
+	mem_write(&cpu, 0xff, 0x77);
+	//while(1){
+	//	mem_write(&cpu, 0xfe, rand()%15 + 1);
+	//	interpret(&cpu);
+	//	printf("%d", OPCODE[cpu.memory[cpu.pc]].instruction);
+	//	printf("%x\n", cpu.pc);
+	//	for(int i=0x0200; i < 0x0600; ++i){
+	//		printf("%d ", cpu.memory[i]);
+	//		if(i%32 == 0) printf("\n");
+	//	}
+	//	printf("\n");
+	//}
+	
+	SetTargetFPS(5000);
+	while(!WindowShouldClose()){
+		if(IsKeyDown(KEY_W)){
+			mem_write(&cpu, 0xff, 0x77);
+		}
+		if(IsKeyDown(KEY_S)){
+			mem_write(&cpu, 0xff, 0x73);
+		}
+		if(IsKeyDown(KEY_A)){
+			mem_write(&cpu, 0xff, 0x61);
+		}
+		if(IsKeyDown(KEY_D)){
+			mem_write(&cpu, 0xff, 0x64);
+		}
+		mem_write(&cpu, 0xfe, rand()%15 + 1);
+
+		interpret(&cpu);
+
+		BeginDrawing();
+		{
+			int block = 0;
+			for(int i=0x0200; i < 0x0600; ++i){
+				uint8_t x = cpu.memory[i];
+				Color c;
+				if(x == 0) c = BLACK;
+				if(x == 1) c = WHITE;
+				if(x == 2 || x == 9) c = GRAY;
+				if(x == 3 || x == 10) c = RED;
+				if(x == 4 || x == 11) c = GREEN;
+				if(x == 5 || x == 12) c = BLUE;
+				if(x == 6 || x == 13) c = MAGENTA;
+				if(x == 7 || x == 14) c = YELLOW;
+		
+				int px, py;
+				py = block/32;
+				px = block%32;
+				DrawRectangle(px * 10, py * 10, 10, 10, c);
+				block++;
+			}
+		}
+		EndDrawing();
+	}
+	return 0;
 }