chore: initial PPU registers testing

src/consts.rs

@@ -7,6 +7,13 @@ pub const TMA_ADDR: u16 = 0xff06;
 pub const TAC_ADDR: u16 = 0xff07;
 pub const IF_ADDR: u16 = 0xff0f;
 
+// PPU registers
+pub const LCDC_ADDR: u16 = 0xff40;
+pub const STAT_ADDR: u16 = 0xff41;
+pub const SCY_ADDR: u16 = 0xff42;
+pub const SCX_ADDR: u16 = 0xff43;
+pub const LY_ADDR: u16 = 0xff44;
+
 // DMA registers
 pub const DMA_ADDR: u16 = 0xff46;
 pub const HDMA1_ADDR: u16 = 0xff51;

src/ppu.rs

@@ -15,6 +15,7 @@ use crate::{
         rgb888_to_rgb565_u16, Pixel, PixelAlpha, RGB1555_SIZE, RGB565_SIZE, RGB888_SIZE, RGB_SIZE,
         XRGB8888_SIZE,
     },
+    consts::{LCDC_ADDR, LY_ADDR, SCX_ADDR, SCY_ADDR, STAT_ADDR},
     gb::{GameBoyConfig, GameBoyMode},
     mmu::BusComponent,
     util::SharedThread,
@@ -782,7 +783,7 @@ impl Ppu {
             // Not Usable
             0xfea0..=0xfeff => 0xff,
             0xff80..=0xfffe => self.hram[(addr & 0x007f) as usize],
-            0xff40 =>
+            LCDC_ADDR =>
             {
                 #[allow(clippy::bool_to_int_with_if)]
                 (if self.switch_bg { 0x01 } else { 0x00 }
@@ -794,17 +795,18 @@ impl Ppu {
                     | if self.window_map { 0x40 } else { 0x00 }
                     | if self.switch_lcd { 0x80 } else { 0x00 })
             }
-            0xff41 => {
+            STAT_ADDR => {
                 (if self.stat_hblank { 0x08 } else { 0x00 }
                     | if self.stat_vblank { 0x10 } else { 0x00 }
                     | if self.stat_oam { 0x20 } else { 0x00 }
                     | if self.stat_lyc { 0x40 } else { 0x00 }
                     | if self.lyc == self.ly { 0x04 } else { 0x00 }
-                    | (self.mode as u8 & 0x03))
+                    | (self.mode as u8 & 0x03)
+                    | 0x80)
             }
-            0xff42 => self.scy,
-            0xff43 => self.scx,
-            0xff44 => self.ly,
+            SCY_ADDR => self.scy,
+            SCX_ADDR => self.scx,
+            LY_ADDR => self.ly,
             0xff45 => self.lyc,
             0xff47 => self.palettes[0],
             0xff48 => self.palettes[1],
@@ -855,7 +857,7 @@ impl Ppu {
             // Not Usable
             0xfea0..=0xfeff => (),
             0xff80..=0xfffe => self.hram[(addr & 0x007f) as usize] = value,
-            0xff40 => {
+            LCDC_ADDR => {
                 self.switch_bg = value & 0x01 == 0x01;
                 self.switch_obj = value & 0x02 == 0x02;
                 self.obj_size = value & 0x04 == 0x04;
@@ -879,14 +881,14 @@ impl Ppu {
                     self.clear_frame_buffer();
                 }
             }
-            0xff41 => {
+            STAT_ADDR => {
                 self.stat_hblank = value & 0x08 == 0x08;
                 self.stat_vblank = value & 0x10 == 0x10;
                 self.stat_oam = value & 0x20 == 0x20;
                 self.stat_lyc = value & 0x40 == 0x40;
             }
-            0xff42 => self.scy = value,
-            0xff43 => self.scx = value,
+            SCY_ADDR => self.scy = value,
+            SCX_ADDR => self.scx = value,
             0xff45 => self.lyc = value,
             0xff47 => {
                 if value == self.palettes[0] {

src/test.rs

@@ -74,7 +74,10 @@ pub fn run_image_test(
 
 #[cfg(test)]
 mod tests {
-    use crate::consts::{DIV_ADDR, IF_ADDR, TAC_ADDR, TIMA_ADDR, TMA_ADDR};
+    use crate::consts::{
+        DIV_ADDR, IF_ADDR, LCDC_ADDR, LY_ADDR, SCX_ADDR, SCY_ADDR, STAT_ADDR, TAC_ADDR, TIMA_ADDR,
+        TMA_ADDR,
+    };
 
     use super::{run_serial_test, run_step_test, TestOptions};
 
@@ -100,6 +103,12 @@ mod tests {
         assert_eq!(result.mmu().read(TMA_ADDR), 0x00);
         assert_eq!(result.mmu().read(TAC_ADDR), 0xf8);
         assert_eq!(result.mmu().read(IF_ADDR), 0xe1);
+
+        assert_eq!(result.ppu().read(LCDC_ADDR), 0x91);
+        assert_eq!(result.ppu().read(STAT_ADDR), 0x81);
+        assert_eq!(result.ppu().read(SCY_ADDR), 0x00);
+        assert_eq!(result.ppu().read(SCX_ADDR), 0x00);
+        assert_eq!(result.ppu().read(LY_ADDR), 0x91);
     }
 
     #[test]