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Experimental interrupts

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This commit is contained in:
Franco Colmenarez
2021-10-29 15:40:47 -05:00
parent f90900a4c1
commit c77bc9db70
4 changed files with 114 additions and 54 deletions
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src/ppu.rs
+27 -21
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@@ -5,7 +5,7 @@ use crate::utils::{
to_bit_index,
};
use crate::bus::{Bus, AddressRange, BANK_ZERO, VIDEO_RAM};
use crate::cpu::{Cycles, InterruptFlag};
use crate::cpu::{Cycles, Interrupt};
#[derive(Debug, Copy, Clone)]
enum Pixel {
@@ -87,25 +87,31 @@ impl PPU {
self.cycles.0 += cycles.0;
}
pub fn do_cycle(&mut self, bus: &mut Bus) {
pub fn do_cycles(&mut self, bus: &mut Bus, cycles: Cycles) {
let mut count = 0;
while count < cycles.0 {
self.cycle(bus);
count += 1;
}
}
pub fn cycle(&mut self, bus: &mut Bus) {
// Mode 1 Vertical blank
if PPU::get_lcd_y(bus) >= 144 {
if PPU::get_lcd_y(bus) == 144 {
bus.set_flag(InterruptFlag::VBlank, true);
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::VBlank), true);
}
bus.set_interrupt(Interrupt::VBlank, true);
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::VBlank), true);
} else {
if self.cycles.0 == 0 {
// Mode 2 OAM scan
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::SearchingOAM), true);
} else if self.cycles.0 == 80 + 1 {
// Mode 3 drawing pixel line. This could also last 289 cycles
bus.set_flag(InterruptFlag::LCDSTAT, true);
bus.set_interrupt(Interrupt::LCDSTAT, true);
self.draw_line(bus);
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::TransferringToLCD), true);
} else if self.cycles.0 == 80 + 172 + 1 {
// Mode 0 Horizontal blank. This could last 87 or 204 cycles depending on the mode 3
bus.set_flag(InterruptFlag::LCDSTAT, true);
bus.set_interrupt(Interrupt::LCDSTAT, true);
PPU::set_lcd_status(bus, LCDStatus::ModeFlag(LCDStatusModeFlag::HBlank), true);
}
}
@@ -113,7 +119,7 @@ impl PPU {
let lyc_compare = PPU::get_lcd_y(bus) == bus.read(LCD_Y_COMPARE_ADDRESS);
PPU::set_lcd_status(bus, LCDStatus::LYCInterrupt, lyc_compare);
if lyc_compare {
bus.set_flag(InterruptFlag::LCDSTAT, true);
bus.set_interrupt(Interrupt::LCDSTAT, true);
}
self.increment_cycles(Cycles(1));
@@ -186,15 +192,15 @@ impl PPU {
pub fn get_lcd_status(bus: &Bus, status: LCDStatus) -> bool {
let byte = bus.read(LCD_STATUS_ADDRESS);
match status {
LCDStatus::LYCInterrupt => get_bit(byte, BitIndex::I6),
LCDStatus::Mode2OAMInterrupt => get_bit(byte, BitIndex::I5),
LCDStatus::LYCInterrupt => get_bit(byte, BitIndex::I6),
LCDStatus::Mode2OAMInterrupt => get_bit(byte, BitIndex::I5),
LCDStatus::Mode1VBlankInterrupt => get_bit(byte, BitIndex::I4),
LCDStatus::Mode0HBlankInterrupt => get_bit(byte, BitIndex::I3),
LCDStatus::LYCFlag => get_bit(byte, BitIndex::I2),
LCDStatus::LYCFlag => get_bit(byte, BitIndex::I2),
LCDStatus::ModeFlag(mode) => match mode {
LCDStatusModeFlag::HBlank => (byte & 0b00000011) == 0,
LCDStatusModeFlag::VBlank => (byte & 0b00000011) == 1,
LCDStatusModeFlag::SearchingOAM => (byte & 0b00000011) == 2,
LCDStatusModeFlag::HBlank => (byte & 0b00000011) == 0,
LCDStatusModeFlag::VBlank => (byte & 0b00000011) == 1,
LCDStatusModeFlag::SearchingOAM => (byte & 0b00000011) == 2,
LCDStatusModeFlag::TransferringToLCD => (byte & 0b00000011) == 3,
},
}
@@ -203,15 +209,15 @@ impl PPU {
fn set_lcd_status(bus: &mut Bus, status: LCDStatus, val: bool) {
let mut byte = bus.read(LCD_STATUS_ADDRESS);
byte = match status {
LCDStatus::LYCInterrupt => set_bit(byte, val, BitIndex::I6),
LCDStatus::Mode2OAMInterrupt => set_bit(byte, val, BitIndex::I5),
LCDStatus::LYCInterrupt => set_bit(byte, val, BitIndex::I6),
LCDStatus::Mode2OAMInterrupt => set_bit(byte, val, BitIndex::I5),
LCDStatus::Mode1VBlankInterrupt => set_bit(byte, val, BitIndex::I4),
LCDStatus::Mode0HBlankInterrupt => set_bit(byte, val, BitIndex::I3),
LCDStatus::LYCFlag => set_bit(byte, val, BitIndex::I2),
LCDStatus::LYCFlag => set_bit(byte, val, BitIndex::I2),
LCDStatus::ModeFlag(mode) => match mode {
LCDStatusModeFlag::HBlank => (byte & 0b11111100) | 0,
LCDStatusModeFlag::VBlank => (byte & 0b11111100) | 1,
LCDStatusModeFlag::SearchingOAM => (byte & 0b11111100) | 2,
LCDStatusModeFlag::HBlank => (byte & 0b11111100) | 0,
LCDStatusModeFlag::VBlank => (byte & 0b11111100) | 1,
LCDStatusModeFlag::SearchingOAM => (byte & 0b11111100) | 2,
LCDStatusModeFlag::TransferringToLCD => (byte & 0b11111100) | 3,
},
};