mirror of
https://github.com/mre/mos6502.git
synced 2025-02-17 17:30:43 +00:00
commit
b0ff12ac33
@ -28,13 +28,27 @@
|
||||
extern crate emu6502;
|
||||
|
||||
use emu6502::machine;
|
||||
use emu6502::address::Address;
|
||||
|
||||
fn main() {
|
||||
let mut machine = machine::Machine::new();
|
||||
|
||||
// "Load" a program
|
||||
machine.memory.set_byte(&Address(0), 0x69); // ADC immediate opcode
|
||||
machine.memory.set_byte(&Address(1), 0x07); // Immediate operand
|
||||
machine.memory.set_byte(&Address(2), 0x69); // ADC immediate opcode
|
||||
machine.memory.set_byte(&Address(3), 0x08); // ADC immediate opcode
|
||||
|
||||
// Obviously this will run the full program, just
|
||||
// executing a finite num of instructions for simplicity
|
||||
// right now.
|
||||
for _ in range(0u, 2u) {
|
||||
let raw_instruction = machine.fetch_instruction();
|
||||
let instruction = machine.decode_instruction(raw_instruction);
|
||||
machine.execute_instruction(instruction);
|
||||
}
|
||||
|
||||
println!("A: {}", machine.registers.accumulator);
|
||||
println!("add_with_carry(1)");
|
||||
machine.add_with_carry(1);
|
||||
println!("A: {}", machine.registers.accumulator);
|
||||
println!("{}", machine);
|
||||
|
||||
}
|
||||
|
||||
|
@ -48,7 +48,9 @@ pub enum Instruction
|
||||
// NV BDIZC A X Y S PC M
|
||||
//
|
||||
// | outputs | inputs
|
||||
{ ADC // ADd with Carry................ | NV ...ZC A = A + M + C
|
||||
{
|
||||
ADC(i8) // ADd with Carry............ | NV ...ZC A = A + M + C
|
||||
|
||||
, AND // logical AND (bitwise)......... | N. ...Z. A = A && M
|
||||
, ASL // Arithmetic Shift Left......... | N. ...ZC A = M << 1
|
||||
, BCC // Branch if Carry Clear......... | .. ..... PC = !C
|
||||
|
@ -25,6 +25,10 @@
|
||||
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
||||
// POSSIBILITY OF SUCH DAMAGE.
|
||||
|
||||
use address::AddressDiff;
|
||||
use std::fmt;
|
||||
use instruction::Instruction;
|
||||
use instruction::{ADC, NOP};
|
||||
use memory::Memory;
|
||||
use registers::{ Registers, Status, StatusArgs };
|
||||
use registers::{ ps_negative, ps_overflow, ps_zero, ps_carry };
|
||||
@ -45,6 +49,35 @@ impl Machine {
|
||||
pub fn reset(&mut self) {
|
||||
*self = Machine::new();
|
||||
}
|
||||
|
||||
pub fn fetch_instruction(&mut self) -> i8 {
|
||||
let instr = self.memory.get_byte(&self.registers.program_counter);
|
||||
|
||||
// Will need smarter logic to fetch the correct number of bytes
|
||||
// for instruction
|
||||
self.registers.program_counter = self.registers.program_counter + AddressDiff(1);
|
||||
instr as i8
|
||||
}
|
||||
|
||||
pub fn decode_instruction(&mut self, raw_instruction: i8) -> Instruction {
|
||||
match raw_instruction {
|
||||
0x69 => ADC(self.fetch_instruction()),
|
||||
_ => NOP
|
||||
}
|
||||
}
|
||||
|
||||
pub fn execute_instruction(&mut self, instruction: Instruction) {
|
||||
match instruction {
|
||||
ADC(immediate) => {
|
||||
println!("executing add with carry");
|
||||
self.add_with_carry(immediate);
|
||||
},
|
||||
NOP => {
|
||||
println!("nop instr");
|
||||
}
|
||||
_ => println!("attempting to execute unimplemented instruction")
|
||||
};
|
||||
}
|
||||
|
||||
// TODO akeeton: Implement binary-coded decimal.
|
||||
pub fn add_with_carry(&mut self, value: i8) {
|
||||
@ -76,6 +109,12 @@ impl Machine {
|
||||
}
|
||||
}
|
||||
|
||||
impl fmt::Show for Machine {
|
||||
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
|
||||
write!(f, "Machine Dump:\n\nAccumulator: {}", self.registers.accumulator)
|
||||
}
|
||||
}
|
||||
|
||||
#[test]
|
||||
fn add_with_carry_test() {
|
||||
|
||||
|
Loading…
x
Reference in New Issue
Block a user