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Refactor 16bit bus read write

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This commit is contained in:
Franco Colmenarez 2021-10-15 19:18:00 -05:00
parent 891a72ad73
commit f9d5cfaa02
2 changed files with 23 additions and 22 deletions
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12
src/bus.rs
View File

@ -1,3 +1,4 @@
use crate::utils::{join_bytes};
use crate::rom::ROM;
pub enum MemoryMap {
@ -46,7 +47,6 @@ impl Bus {
Ok(rom) => rom,
_ => ROM::from_bytes(&[0; 0xFFFF])
};
game_rom.print_content(Some(0x102));
Self {
data: [0; 0x10000],
game_rom,
@ -62,7 +62,17 @@ impl Bus {
}
}
pub fn read_16bit(&self, address: u16) -> u16 {
join_bytes(self.read(address + 1), self.read(address))
}
pub fn write(&mut self, address: u16, data: u8) {
self.data[address as usize] = data;
}
pub fn write_16bit(&mut self, address: u16, data: u16) {
let bytes = data.to_be_bytes();
self.write(address, bytes[1]);
self.write(address + 1, bytes[0]);
}
}

33
src/cpu.rs
View File

@ -274,14 +274,14 @@ impl CPU {
pub fn run(&mut self, bus: &mut Bus) {
let program_counter = self.registers.get(Register::PC);
let parameter_bytes = CPU::read_parameter_bytes(program_counter, bus);
println!("{:02X?}", &parameter_bytes);
let opcode = CPU::parse_opcode(&parameter_bytes);
println!("{:?}", opcode);
println!("PC: {:04X?}", self.registers.get(Register::PC));
println!("{:02X?}", &parameter_bytes);
self.exec(opcode, bus);
}
pub fn exec(&mut self, opcode: Opcode, bus: &mut Bus) {
println!("Executing {:?}", opcode);
println!("Current PC: {:02X?}", self.registers.get(Register::PC));
match opcode {
// Load
Opcode::LD(params) => match params {
@ -294,10 +294,7 @@ impl CPU {
let bytes = value.to_be_bytes();
match register.is_8bit() {
true => bus.write(address, bytes[1]),
false => {
bus.write(address, bytes[1]);
bus.write(address + 1, bytes[0]);
}
false => bus.write_16bit(address, value),
}
self.registers.increment(Register::PC, 3);
},
@ -353,11 +350,10 @@ impl CPU {
// CALL
Opcode::CALL(params) => match params {
OpcodeParameter::U16(address) => {
let pc_bytes = self.registers.get(Register::PC).to_be_bytes();
let pc = self.registers.get(Register::PC);
self.registers.decrement(Register::SP, 2);
let sp = self.registers.get(Register::SP);
bus.write(sp, pc_bytes[1]);
bus.write(sp + 1, pc_bytes[0]);
bus.write_16bit(sp, pc);
self.registers.set(Register::PC, address);
},
_ => {},
@ -368,7 +364,7 @@ impl CPU {
Opcode::POP(register) => {
if register.is_16bit() {
let sp = self.registers.get(Register::SP);
let val = join_bytes(bus.read(sp + 1), bus.read(sp));
let val = bus.read_16bit(sp);
self.registers.set(register, val);
self.registers.increment(Register::SP, 2);
}
@ -751,8 +747,7 @@ mod tests {
let mut bus = Bus::new();
cpu.registers.set(Register::SP, 0x1234);
cpu.exec(Opcode::LD(OpcodeParameter::U16_Register(0xF0F0, Register::SP)), &mut bus);
assert_eq!(bus.read(0xF0F0), 0x34);
assert_eq!(bus.read(0xF0F1), 0x12);
assert_eq!(bus.read_16bit(0xF0F0), 0x1234);
assert_eq!(cpu.registers.get(Register::PC), 0x103);
// JP
@ -803,8 +798,7 @@ mod tests {
cpu.registers.set(Register::SP, sp);
cpu.registers.set(Register::PC, 0x1234);
cpu.exec(Opcode::CALL(OpcodeParameter::U16(0xF0F0)), &mut bus);
assert_eq!(bus.read(sp - 2), 0x34);
assert_eq!(bus.read(sp - 1), 0x12);
assert_eq!(bus.read_16bit(sp - 2), 0x1234);
assert_eq!(cpu.registers.get(Register::SP), sp - 2);
assert_eq!(cpu.registers.get(Register::PC), 0xF0F0);
@ -814,8 +808,7 @@ mod tests {
cpu.registers.set(Register::SP, sp);
cpu.registers.set(Register::PC, 0x1234);
cpu.exec(Opcode::RST(0xF0), &mut bus);
assert_eq!(bus.read(sp - 2), 0x34);
assert_eq!(bus.read(sp - 1), 0x12);
assert_eq!(bus.read_16bit(sp - 2), 0x1234);
assert_eq!(cpu.registers.get(Register::SP), sp - 2);
assert_eq!(cpu.registers.get(Register::PC), 0x00F0);
@ -823,8 +816,7 @@ mod tests {
let mut cpu = CPU::new();
let sp = 0xFFDF;
cpu.registers.set(Register::SP, sp);
bus.write(sp, 0x34);
bus.write(sp + 1, 0x12);
bus.write_16bit(sp, 0x1234);
cpu.exec(Opcode::POP(Register::HL), &mut bus);
assert_eq!(cpu.registers.get(Register::HL), 0x1234);
assert_eq!(cpu.registers.get(Register::SP), sp + 2);
@ -833,8 +825,7 @@ mod tests {
let mut cpu = CPU::new();
let sp = 0xFFDF;
cpu.registers.set(Register::SP, sp);
bus.write(sp, 0x34);
bus.write(sp + 1, 0x12);
bus.write_16bit(sp, 0x1234);
cpu.exec(Opcode::RET(OpcodeParameter::NoParam), &mut bus);
assert_eq!(cpu.registers.get(Register::PC), 0x1234);
assert_eq!(cpu.registers.get(Register::SP), sp + 2);