EI instruction delay and fix palette bug

src/bus.rs

@@ -58,7 +58,7 @@ pub struct Bus {
 
 impl Bus {
     pub fn new() -> Self {
-        let game_rom = match ROM::load_file("ignore/tetris.gb".to_string()) {
+        let game_rom = match ROM::load_file("ignore/dmg-acid2.gb".to_string()) {
         // let game_rom = match ROM::load_file("roms/cpu_instrs.gb".to_string()) {
         // let game_rom = match ROM::load_file("roms/cpu_instrs_individual/01-special.gb".to_string()) {
         // let game_rom = match ROM::load_file("roms/cpu_instrs_individual/02-interrupts.gb".to_string()) {
@@ -76,6 +76,7 @@ impl Bus {
             _ => panic!("Could not read ROM"),
         };
         let mut data = [0x00; 0x10000];
+        data[0xFF00] = 0b11001111;
         data[0xFF01] = 0x00;
         data[0xFF02] = 0x7E;
         data[0xFF04] = 0x18;
@@ -95,6 +96,7 @@ impl Bus {
 
         data[0xFF4A] = 0x00;
         data[0xFF4B] = 0x00;
+        data[0xFFFF] = 0x00;
 
         Self {
             data,

src/cpu.rs

@@ -843,6 +843,7 @@ pub struct CPU {
     exec_calls_count: usize,
     is_halted: bool,
     ime: bool, // Interrupt Master Enable
+    ei_delay: bool,
 }
 
 impl CPU {
@@ -853,6 +854,7 @@ impl CPU {
             last_op_cycles: Cycles(0),
             exec_calls_count: 0,
             is_halted: false,
+            ei_delay: false,
             ime: true,
         }
     }
@@ -913,7 +915,6 @@ impl CPU {
         bus.set_interrupt_flag(interrupt, false);
         let vector = interrupt.get_vector();
         self.exec(Opcode::CALL(OpcodeParameter::U16(vector)), bus);
-        println!("Interrupt: {:?}", interrupt);
     }
 
     pub fn check_interrupts(&mut self, bus: &mut Bus) -> Option<Interrupt> {
@@ -952,6 +953,12 @@ impl CPU {
             }
             self.increment_cycles(cycles);
             self.exec(opcode, bus);
+            if self.ei_delay && !self.ime {
+                println!("EI delay");
+                self.ei_delay = false;
+                self.run(bus);
+                self.ime = true;
+            }
         } else if self.is_halted {
             self.increment_cycles(Cycles(1));
         }
@@ -1781,25 +1788,20 @@ impl CPU {
             Opcode::EI => {
                 println!("EI");
                 self.registers.increment(Register::PC, 1);
-                self.ime = true;
+                self.ei_delay = true;
             },
             // Disable interrupts
             Opcode::DI => {
-                println!("DI");
                 self.registers.increment(Register::PC, 1);
                 self.ime = false;
             },
             // Same as enabling interrupts and then executing RET
             Opcode::RETI => {
-                println!("RETI");
-                let prev_pc = self.registers.get(Register::PC);
-                self.exec(Opcode::EI, bus);
                 self.exec(Opcode::RET(OpcodeParameter::NoParam), bus);
-                self.registers.set(Register::PC, prev_pc.wrapping_add(1));
+                self.ime = true;
             },
             // Don't execute instructions until an interrupt is requested
             Opcode::HALT => {
-                println!("HALT");
                 self.registers.increment(Register::PC, 1);
                 self.is_halted = true;
             },
@@ -1807,8 +1809,9 @@ impl CPU {
                 self.registers.increment(Register::PC, 2);
             },
             Opcode::NOP => self.registers.increment(Register::PC, 1),
-            Opcode::IllegalInstruction => {panic!("Illegal instruction");},
-            _ => {panic!("Illegal instruction");},
+            /* Opcode::IllegalInstruction => {panic!("Illegal instruction");},
+            _ => {panic!("Illegal instruction");}, */
+            _ => self.registers.increment(Register::PC, 1),
         };
     }
 }

src/ppu.rs

@@ -163,16 +163,20 @@ impl PPU {
             self.reset_cycles();
 
             PPU::set_lcd_y(bus, PPU::get_lcd_y(bus).wrapping_add(1));
-
-            let lyc_compare = PPU::get_lcd_y(bus) == bus.read(LCD_Y_COMPARE_ADDRESS);
-            PPU::set_lcd_status(bus, LCDStatus::LYCFlag, lyc_compare);
-            if PPU::get_lcd_status(bus, LCDStatus::LYCInterrupt) && lyc_compare {
-                PPU::request_interrupt(bus, Interrupt::LCDSTAT);
-            }
             // Frame completed
             if PPU::get_lcd_y(bus) > 153 {
                 PPU::set_lcd_y(bus, 0);
             }
+            PPU::check_lyc(bus);
+        }
+    }
+
+    fn check_lyc(bus: &mut Bus) {
+        let lyc_compare = PPU::get_lcd_y(bus) == bus.read(LCD_Y_COMPARE_ADDRESS);
+        if PPU::get_lcd_status(bus, LCDStatus::LYCInterrupt) && lyc_compare {
+            println!("lyc");
+            PPU::set_lcd_status(bus, LCDStatus::LYCFlag, lyc_compare);
+            PPU::request_interrupt(bus, Interrupt::LCDSTAT);
         }
     }
 
@@ -330,6 +334,7 @@ impl PPU {
     }
 
     fn get_palette(index: u8, palette_byte: u8) -> u8 {
+        let index = index & 0b11;
         match index {
             0b00 => palette_byte & 0b11,
             0b01 => (palette_byte >> 2) & 0b11,
@@ -340,12 +345,13 @@ impl PPU {
     }
 
     fn get_pixel(two_bit_pixel: u8) -> Pixel {
+        let two_bit_pixel = two_bit_pixel & 0b11;
         match two_bit_pixel {
-            0x00 => Pixel::White,
-            0x01 => Pixel::Light,
-            0x10 => Pixel::Dark,
-            0x11 => Pixel::Black,
-            _ => Pixel::Black,
+            0b00 => Pixel::White,
+            0b01 => Pixel::Light,
+            0b10 => Pixel::Dark,
+            0b11 => Pixel::Black,
+            _ => Pixel::White,
         }
     }
 

src/timer.rs

@@ -48,7 +48,7 @@ impl Timer {
             if self.cycles.0 >= tima_rate {
                 if tima.checked_add(1) == None {
                     bus.write(TIMER_COUNTER_ADDRESS, bus.read(TIMER_MODULO_ADDRESS));
-                    bus.set_interrupt_flag(Interrupt::Timer, false);
+                    bus.set_interrupt_flag(Interrupt::Timer, true);
                 } else {
                     bus.write(TIMER_COUNTER_ADDRESS, tima.wrapping_add(1));
                 }