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fix(joypad): fix bug where gameboy overwrites read only bits

This commit is contained in:
Rekai Nyangadzayi Musuka 2021-05-03 23:37:30 -05:00
parent 4abb2833c4
commit 5a59c31b72
2 changed files with 11 additions and 7 deletions
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2
src/bus.rs
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@ -243,7 +243,7 @@ impl Bus {
0xFF00..=0xFF7F => { 0xFF00..=0xFF7F => {
// IO Registers // IO Registers
match addr { match addr {
0xFF00 => self.joypad.status = byte.into(), 0xFF00 => self.joypad.status.update(byte),
0xFF01 => self.serial.next = byte, 0xFF01 => self.serial.next = byte,
0xFF02 => self.serial.control = byte.into(), 0xFF02 => self.serial.control = byte.into(),
0xFF04 => self.timer.divider = 0x00, 0xFF04 => self.timer.divider = 0x00,

16
src/joypad.rs
View File

@ -27,6 +27,16 @@ bitfield! {
from into ButtonState, right_a, _set_right_a: 0, 0; from into ButtonState, right_a, _set_right_a: 0, 0;
} }
impl JoypadStatus {
pub(crate) fn update(&mut self, byte: u8) {
let action_row = (byte >> 5) & 0x01;
let direction_row = (byte >> 4) & 0x01;
self.set_action_row(action_row.into());
self.set_direction_row(direction_row.into());
}
}
impl JoypadStatus { impl JoypadStatus {
pub fn set_down_start(&mut self, state: ButtonState, int: &mut bool) { pub fn set_down_start(&mut self, state: ButtonState, int: &mut bool) {
if !(*int) { if !(*int) {
@ -74,12 +84,6 @@ impl Clone for JoypadStatus {
} }
} }
impl From<u8> for JoypadStatus {
fn from(byte: u8) -> Self {
Self(byte)
}
}
impl From<JoypadStatus> for u8 { impl From<JoypadStatus> for u8 {
fn from(status: JoypadStatus) -> Self { fn from(status: JoypadStatus) -> Self {
status.0 status.0