Add blending and mosaic SFX, and cleanup code.

Former-commit-id: b9f0ccaf1820da61f49ebeb2af5beff5cccd722f

Cargo.lock

@@ -599,6 +599,7 @@ dependencies = [
  "ansi_term 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "bit 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "bitfield 0.13.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "bitflags 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "clap 2.33.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "colored 1.8.0 (registry+https://github.com/rust-lang/crates.io-index)",

Cargo.toml

@@ -20,6 +20,7 @@ sdl2 = "0.32.2"
 minifb = "0.11.2"
 time = "0.1.42"
 bitfield = "0.13.1"
+bitflags = "1.1.0"
 
 [profile.dev]
 opt-level = 1

src/backend/minifb_backend.rs

@@ -7,7 +7,7 @@ extern crate minifb;
 use minifb::{Key, Window, WindowOptions};
 
 use super::EmulatorBackend;
-use crate::core::gpu::Gpu;
+use crate::core::gpu::{DISPLAY_HEIGHT, DISPLAY_WIDTH};
 use crate::core::keypad;
 
 pub struct MinifbBackend {
@@ -20,8 +20,8 @@ impl MinifbBackend {
     pub fn new() -> MinifbBackend {
         let window = Window::new(
             "rustboyadvance-ng",
-            Gpu::DISPLAY_WIDTH,
+            DISPLAY_WIDTH,
-            Gpu::DISPLAY_HEIGHT,
+            DISPLAY_HEIGHT,
             WindowOptions {
                 borderless: true,
                 scale: minifb::Scale::X4,
@@ -39,7 +39,7 @@ impl MinifbBackend {
 }
 
 impl EmulatorBackend for MinifbBackend {
-    fn render(&mut self, buffer: Vec<u32>) {
+    fn render(&mut self, buffer: &[u32]) {
         self.frames_rendered += 1;
         if self.first_frame_start.elapsed() >= time::Duration::from_secs(1) {
             let title = format!("rustboyadvance-ng ({} fps)", self.frames_rendered);
@@ -47,7 +47,7 @@ impl EmulatorBackend for MinifbBackend {
             self.first_frame_start = time::Instant::now();
             self.frames_rendered = 0;
         }
-        self.window.update_with_buffer(&buffer).unwrap();
+        self.window.update_with_buffer(buffer).unwrap();
     }
 
     fn get_key_state(&mut self) -> u16 {

src/backend/mod.rs

@@ -7,7 +7,7 @@ mod sdl2_backend;
 pub use sdl2_backend::Sdl2Backend;
 
 pub trait EmulatorBackend {
-    fn render(&mut self, buffer: Vec<u32>);
+    fn render(&mut self, buffer: &[u32]);
 
     fn get_key_state(&mut self) -> u16;
 }
@@ -24,5 +24,5 @@ impl EmulatorBackend for DummyBackend {
     fn get_key_state(&mut self) -> u16 {
         keypad::KEYINPUT_ALL_RELEASED
     }
-    fn render(&mut self, _buffer: Vec<u32>) {}
+    fn render(&mut self, _buffer: &[u32]) {}
 }

src/backend/sdl2_backend.rs

@@ -1,4 +1,3 @@
-use std::convert::TryFrom;
 use std::time;
 
 use crate::bit::BitIndex;
@@ -6,13 +5,13 @@ use crate::bit::BitIndex;
 extern crate sdl2;
 use sdl2::event::Event;
 use sdl2::keyboard::Keycode;
-use sdl2::pixels::{Color, PixelFormat, PixelFormatEnum};
+use sdl2::pixels::{Color, PixelFormatEnum};
 use sdl2::rect::{Point, Rect};
-use sdl2::render::{Texture, TextureCreator, WindowCanvas};
+use sdl2::render::{TextureCreator, WindowCanvas};
-use sdl2::video::{Window, WindowContext};
+use sdl2::video::WindowContext;
 
 use super::EmulatorBackend;
-use crate::core::gpu::Gpu;
+use crate::core::gpu::{DISPLAY_HEIGHT, DISPLAY_WIDTH};
 use crate::core::keypad;
 
 pub struct Sdl2Backend {
@@ -24,8 +23,8 @@ pub struct Sdl2Backend {
     keyinput: u16,
 }
 
-const SCREEN_WIDTH: u32 = Gpu::DISPLAY_WIDTH as u32;
+const SCREEN_WIDTH: u32 = DISPLAY_WIDTH as u32;
-const SCREEN_HEIGHT: u32 = Gpu::DISPLAY_HEIGHT as u32;
+const SCREEN_HEIGHT: u32 = DISPLAY_HEIGHT as u32;
 
 impl Sdl2Backend {
     pub fn new() -> Sdl2Backend {
@@ -57,7 +56,7 @@ impl Sdl2Backend {
 }
 
 impl EmulatorBackend for Sdl2Backend {
-    fn render(&mut self, buffer: Vec<u32>) {
+    fn render(&mut self, buffer: &[u32]) {
         let mut texture = self
             .tc
             .create_texture_target(PixelFormatEnum::RGB24, SCREEN_WIDTH, SCREEN_HEIGHT)

src/bin/main.rs

@@ -65,10 +65,9 @@ fn run_emulator(matches: &ArgMatches) -> GBAResult<()> {
         loop {
             let start_time = time::Instant::now();
             gba.frame();
-            let time_passed = time::Instant::now() - start_time;
+            let time_passed = start_time.elapsed();
             if time_passed <= frame_time {
-                let duration = frame_time - time_passed;
+                ::std::thread::sleep(frame_time - time_passed);
-                ::std::thread::sleep(duration);
             }
         }
     }

src/core/gba.rs

@@ -66,7 +66,7 @@ impl GameBoyAdvance {
             let cycles = self.emulate_cpu();
             self.emulate_peripherals(cycles);
         }
-        self.backend.render(self.io.borrow().gpu.render());
+        self.backend.render(self.io.borrow().gpu.get_framebuffer());
         while self.io.borrow().gpu.state == GpuState::VBlank {
             let cycles = self.emulate_cpu();
             self.emulate_peripherals(cycles);
@@ -106,7 +106,7 @@ impl GameBoyAdvance {
         self.emulate_peripherals(cycles);
 
         if self.io.borrow().gpu.state == GpuState::VBlank {
-            self.backend.render(self.io.borrow().gpu.render());
+            self.backend.render(self.io.borrow().gpu.get_framebuffer());
         }
 
         Ok(executed_insn)

src/core/gpu/blend.rs

@@ -0,0 +1,117 @@
+use std::cmp;
+use std::ops::Sub;
+
+use super::regs::*;
+use super::*;
+
+#[derive(Debug, Primitive, Clone, Copy)]
+pub enum BldMode {
+    BldNone = 0b00,
+    BldAlpha = 0b01,
+    BldWhite = 0b10,
+    BldBlack = 0b11,
+}
+
+impl From<u16> for BldMode {
+    fn from(v: u16) -> BldMode {
+        BldMode::from_u16(v).unwrap()
+    }
+}
+
+impl Rgb15 {
+    fn blend_with(self, other: Rgb15, my_weight: u16, other_weight: u16) -> Rgb15 {
+        let r = cmp::min(31, (self.r() * my_weight + other.r() * other_weight) >> 4);
+        let g = cmp::min(31, (self.g() * my_weight + other.g() * other_weight) >> 4);
+        let b = cmp::min(31, (self.b() * my_weight + other.b() * other_weight) >> 4);
+        Rgb15::from_rgb(r, g, b)
+    }
+}
+
+impl Gpu {
+    fn get_topmost_color(
+        &self,
+        sb: &SysBus,
+        screen_x: usize,
+        layers: &BlendFlags,
+    ) -> Option<Rgb15> {
+        // TODO - only BGs are supported, don't forget OBJs
+
+        let mut color: Option<Rgb15> = None;
+
+        // priorities are 0-4 when 0 is the highest
+        'outer: for priority in 0..4 {
+            for bg in 0..4 {
+                let c = self.bg[bg].line[screen_x];
+                if self.dispcnt.disp_bg(bg)
+                    && !c.is_transparent()
+                    && (layers.is_empty() || layers.contains(BG_LAYER_FLAG[bg]))
+                    && self.bg[bg].bgcnt.priority() == priority
+                {
+                    color = Some(c);
+                    break 'outer;
+                }
+            }
+        }
+        if color.is_none() && layers.contains(BlendFlags::BACKDROP) {
+            color = Some(Rgb15(sb.palette_ram.read_16(0)))
+        }
+        color
+    }
+
+    pub fn blend_line(&mut self, sb: &mut SysBus) -> Scanline {
+        let mut bld_line = Scanline::default();
+        let bldmode = self.bldcnt.mode();
+        match bldmode {
+            BldMode::BldAlpha => {
+                let top_layers = self.bldcnt.top();
+                let bottom_layers = self.bldcnt.bottom();
+
+                for x in 0..DISPLAY_WIDTH {
+                    if let Some(top_color) = self.get_topmost_color(sb, x, &top_layers) {
+                        if let Some(bot_color) = self.get_topmost_color(sb, x, &bottom_layers) {
+                            let eva = self.bldalpha.eva();
+                            let evb = self.bldalpha.evb();
+                            bld_line[x] = top_color.blend_with(bot_color, eva, evb);
+                        } else {
+                            bld_line[x] = top_color;
+                        }
+                    } else {
+                        bld_line[x] = self.get_topmost_color(sb, x, &BlendFlags::all()).unwrap();
+                    }
+                }
+            }
+            BldMode::BldWhite => {
+                let top_layers = self.bldcnt.top();
+                let evy = self.bldy;
+
+                for x in 0..DISPLAY_WIDTH {
+                    bld_line[x] =
+                        if let Some(top_color) = self.get_topmost_color(sb, x, &top_layers) {
+                            top_color.blend_with(Rgb15::WHITE, 16 - evy, evy)
+                        } else {
+                            self.get_topmost_color(sb, x, &BlendFlags::all()).unwrap()
+                        };
+                }
+            }
+            BldMode::BldBlack => {
+                let top_layers = self.bldcnt.top();
+                let evy = self.bldy;
+
+                for x in 0..DISPLAY_WIDTH {
+                    bld_line[x] =
+                        if let Some(top_color) = self.get_topmost_color(sb, x, &top_layers) {
+                            top_color.blend_with(Rgb15::BLACK, 16 - evy, evy)
+                        } else {
+                            self.get_topmost_color(sb, x, &BlendFlags::all()).unwrap()
+                        };
+                }
+            }
+            BldMode::BldNone => {
+                for x in 0..DISPLAY_WIDTH {
+                    bld_line[x] = self.get_topmost_color(sb, x, &BlendFlags::all()).unwrap();
+                }
+            }
+        }
+        bld_line
+    }
+}

src/core/gpu/mod.rs

@@ -1,16 +1,68 @@
 use std::fmt;
 
 use super::arm7tdmi::{Addr, Bus};
-pub use super::palette::{PixelFormat, Rgb15};
 use super::*;
 
 use crate::bitfield::Bit;
 use crate::num::FromPrimitive;
 
+mod blend;
+mod mosaic;
+
 mod regs;
 pub use regs::*;
 
 pub const VRAM_ADDR: Addr = 0x0600_0000;
+pub const DISPLAY_WIDTH: usize = 240;
+pub const DISPLAY_HEIGHT: usize = 160;
+
+const CYCLES_PIXEL: usize = 4;
+const CYCLES_HDRAW: usize = 960;
+const CYCLES_HBLANK: usize = 272;
+const CYCLES_SCANLINE: usize = 1232;
+const CYCLES_VDRAW: usize = 197120;
+const CYCLES_VBLANK: usize = 83776;
+
+const TILE_SIZE: u32 = 0x20;
+
+// TODO - remove the one in palette.rs
+bitfield! {
+    #[derive(Copy, Clone, Default)]
+    pub struct Rgb15(u16);
+    impl Debug;
+    pub r, set_r: 4, 0;
+    pub g, set_g: 9, 5;
+    pub b, set_b: 14, 10;
+    pub is_transparent, _ : 15;
+}
+
+impl Rgb15 {
+    pub const BLACK: Rgb15 = Rgb15(0);
+    pub const WHITE: Rgb15 = Rgb15(0x7fff);
+    pub const TRANSPARENT: Rgb15 = Rgb15(0x8000);
+
+    pub fn to_rgb24(&self) -> u32 {
+        ((self.r() as u32) << 19) | ((self.g() as u32) << 11) | ((self.b() as u32) << 3)
+    }
+
+    pub fn from_rgb(r: u16, g: u16, b: u16) -> Rgb15 {
+        let mut c = Rgb15(0);
+        c.set_r(r);
+        c.set_g(g);
+        c.set_b(b);
+        c
+    }
+
+    pub fn get_rgb(&self) -> (u16, u16, u16) {
+        (self.r(), self.g(), self.b())
+    }
+}
+
+#[derive(Debug, Primitive, Copy, Clone)]
+pub enum PixelFormat {
+    BPP4 = 0,
+    BPP8 = 1,
+}
 
 #[derive(Debug, Primitive, Clone, Copy)]
 pub enum BGMode {
@@ -41,21 +93,20 @@ impl Default for GpuState {
 }
 use GpuState::*;
 
-pub struct FrameBuffer([Rgb15; 512 * 512]);
+pub struct FrameBuffer([u32; DISPLAY_WIDTH * DISPLAY_HEIGHT]);
 
 impl fmt::Debug for FrameBuffer {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         write!(f, "FrameBuffer: ")?;
         for i in 0..6 {
-            let (r, g, b) = self.0[i].get_rgb24();
+            write!(f, "#{:06x}, ", self[i])?;
-            write!(f, "#{:x}{:x}{:x}, ", r, g, b)?;
         }
         write!(f, "...")
     }
 }
 
 impl std::ops::Index<usize> for FrameBuffer {
-    type Output = Rgb15;
+    type Output = u32;
     fn index(&self, index: usize) -> &Self::Output {
         &self.0[index]
     }
@@ -67,67 +118,108 @@ impl std::ops::IndexMut<usize> for FrameBuffer {
     }
 }
 
+#[derive(Copy, Clone)]
+pub struct Scanline([Rgb15; DISPLAY_WIDTH]);
+
+impl Default for Scanline {
+    fn default() -> Scanline {
+        Scanline([Rgb15(0); DISPLAY_WIDTH])
+    }
+}
+
+impl fmt::Debug for Scanline {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        write!(f, "Scanline: ")?;
+        for i in 0..6 {
+            write!(f, "#{:06x}, ", self[i].0)?;
+        }
+        write!(f, "...")
+    }
+}
+
+impl std::ops::Index<usize> for Scanline {
+    type Output = Rgb15;
+    fn index(&self, index: usize) -> &Self::Output {
+        &self.0[index]
+    }
+}
+
+impl std::ops::IndexMut<usize> for Scanline {
+    fn index_mut(&mut self, index: usize) -> &mut Self::Output {
+        &mut self.0[index]
+    }
+}
+
+#[derive(Debug, Default, Copy, Clone)]
+pub struct Bg {
+    pub bgcnt: BgControl,
+    pub bgvofs: u16,
+    pub bghofs: u16,
+    line: Scanline,
+
+    // for mosaic
+    mosaic_first_row: Scanline,
+}
+
+#[derive(Debug, Default, Copy, Clone)]
+pub struct BgAffine {
+    pub pa: i16, // dx
+    pub pb: i16, // dmx
+    pub pc: i16, // dy
+    pub pd: i16, // dmy
+    pub x: i32,
+    pub y: i32,
+}
+
 #[derive(Debug)]
 pub struct Gpu {
     // registers
     pub dispcnt: DisplayControl,
     pub dispstat: DisplayStatus,
-    pub bgcnt: [BgControl; 4],
+
-    pub bgvofs: [u16; 4],
+    pub bg: [Bg; 4],
-    pub bghofs: [u16; 4],
+    pub bg_aff: [BgAffine; 2],
+
     pub win0h: u16,
     pub win1h: u16,
     pub win0v: u16,
     pub win1v: u16,
     pub winin: u16,
     pub winout: u16,
-    pub mosaic: u16,
+    pub mosaic: RegMosaic,
-    pub bldcnt: u16,
+    pub bldcnt: BlendControl,
-    pub bldalpha: u16,
+    pub bldalpha: BlendAlpha,
     pub bldy: u16,
 
     cycles: usize,
 
-    pub pixeldata: FrameBuffer,
+    pub frame_buffer: FrameBuffer,
     pub state: GpuState,
     pub current_scanline: usize, // VCOUNT
 }
 
 impl Gpu {
-    pub const DISPLAY_WIDTH: usize = 240;
-    pub const DISPLAY_HEIGHT: usize = 160;
-
-    pub const CYCLES_PIXEL: usize = 4;
-    pub const CYCLES_HDRAW: usize = 960;
-    pub const CYCLES_HBLANK: usize = 272;
-    pub const CYCLES_SCANLINE: usize = 1232;
-    pub const CYCLES_VDRAW: usize = 197120;
-    pub const CYCLES_VBLANK: usize = 83776;
-
-    pub const TILE_SIZE: u32 = 0x20;
-
     pub fn new() -> Gpu {
         Gpu {
             dispcnt: DisplayControl(0x80),
             dispstat: DisplayStatus(0),
-            bgcnt: [BgControl(0), BgControl(0), BgControl(0), BgControl(0)],
+            bg: [Bg::default(); 4],
-            bgvofs: [0; 4],
+            bg_aff: [BgAffine::default(); 2],
-            bghofs: [0; 4],
             win0h: 0,
             win1h: 0,
             win0v: 0,
             win1v: 0,
             winin: 0,
             winout: 0,
-            mosaic: 0,
+            mosaic: RegMosaic(0),
-            bldcnt: 0,
+            bldcnt: BlendControl(0),
-            bldalpha: 0,
+            bldalpha: BlendAlpha(0),
             bldy: 0,
 
             state: HDraw,
             current_scanline: 0,
             cycles: 0,
-            pixeldata: FrameBuffer([Rgb15::from(0); 512 * 512]),
+            frame_buffer: FrameBuffer([0; DISPLAY_WIDTH * DISPLAY_HEIGHT]),
         }
     }
 
@@ -143,30 +235,35 @@ impl Gpu {
         let ofs = addr - VRAM_ADDR;
         match format {
             PixelFormat::BPP4 => {
-                let byte = sb.vram.read_8(ofs + index2d!(x / 2, y, 4));
+                let byte = sb.vram.read_8(ofs + index2d!(Addr, x / 2, y, 4));
                 if x & 1 != 0 {
                     (byte >> 4) as usize
                 } else {
                     (byte & 0xf) as usize
                 }
             }
-            PixelFormat::BPP8 => sb.vram.read_8(ofs + index2d!(x, y, 8)) as usize,
+            PixelFormat::BPP8 => sb.vram.read_8(ofs + index2d!(Addr, x, y, 8)) as usize,
         }
     }
 
     pub fn get_palette_color(&self, sb: &SysBus, index: u32, palette_index: u32) -> Rgb15 {
-        sb.palette_ram
+        if index == 0 || (palette_index != 0 && index % 16 == 0) {
-            .read_16(2 * index + 0x20 * palette_index)
+            return Rgb15::TRANSPARENT;
-            .into()
+        }
+        Rgb15(sb.palette_ram.read_16(2 * index + 0x20 * palette_index))
     }
 
-    fn scanline_mode0(&mut self, bg: usize, sb: &mut SysBus) {
+    fn render_pixel(&mut self, x: i32, y: i32, p: Rgb15) {
-        let (h_ofs, v_ofs) = (self.bghofs[bg] as u32, self.bgvofs[bg] as u32);
+        self.frame_buffer.0[index2d!(usize, x, y, DISPLAY_WIDTH)] = p.to_rgb24();
-        let tileset_base = self.bgcnt[bg].char_block() - VRAM_ADDR;
+    }
-        let tilemap_base = self.bgcnt[bg].screen_block() - VRAM_ADDR;
-        let (tile_size, pixel_format) = self.bgcnt[bg].tile_format();
 
-        let (bg_width, bg_height) = self.bgcnt[bg].size_regular();
+    fn scanline_reg_bg(&mut self, bg: usize, sb: &mut SysBus) {
+        let (h_ofs, v_ofs) = (self.bg[bg].bghofs as u32, self.bg[bg].bgvofs as u32);
+        let tileset_base = self.bg[bg].bgcnt.char_block();
+        let tilemap_base = self.bg[bg].bgcnt.screen_block();
+        let (tile_size, pixel_format) = self.bg[bg].bgcnt.tile_format();
+
+        let (bg_width, bg_height) = self.bg[bg].bgcnt.size_regular();
 
         let screen_y = self.current_scanline as u32;
         let mut screen_x = 0;
@@ -186,65 +283,70 @@ impl Gpu {
             (256, 256) => 0,
             (512, 256) => bg_x / 256,
             (256, 512) => bg_y / 256,
-            (512, 512) => index2d!(bg_x / 256, bg_y / 256, 2),
+            (512, 512) => index2d!(u32, bg_x / 256, bg_y / 256, 2),
             _ => unreachable!(),
         } as u32;
 
-        let se_row = (bg_x / 8) % 32;
+        let mut se_row = (bg_x / 8) % 32;
         let se_column = (bg_y / 8) % 32;
 
         // this will be non-zero if the h-scroll lands in a middle of a tile
         let mut start_tile_x = bg_x % 8;
+        let tile_py = (bg_y % 8) as u32;
 
-        for t in 0..32 {
+        loop {
-            let map_addr = tilemap_base
+            let mut map_addr = tilemap_base
                 + SCREEN_BLOCK_SIZE * screen_block
-                + 2 * (index2d!((se_row + t) % 32, se_column, 32) as u32);
+                + 2 * index2d!(u32, se_row, se_column, 32);
-            let entry = TileMapEntry(sb.vram.read_16(map_addr - VRAM_ADDR));
+            for _ in se_row..32 {
-            let tile_addr = tileset_base + entry.tile_index() * tile_size;
+                let entry = TileMapEntry(sb.vram.read_16(map_addr - VRAM_ADDR));
+                let tile_addr = tileset_base + entry.tile_index() * tile_size;
 
-            for tile_px in start_tile_x..=7 {
+                for tile_px in start_tile_x..=7 {
-                let tile_py = (bg_y % 8) as u32;
+                    let index = self.read_pixel_index(
-                let index = self.read_pixel_index(
+                        sb,
-                    sb,
+                        tile_addr,
-                    tile_addr,
+                        if entry.x_flip() { 7 - tile_px } else { tile_px },
-                    if entry.x_flip() { 7 - tile_px } else { tile_px },
+                        if entry.y_flip() { 7 - tile_py } else { tile_py },
-                    if entry.y_flip() { 7 - tile_py } else { tile_py },
+                        pixel_format,
-                    pixel_format,
+                    );
-                );
+                    let palette_bank = match pixel_format {
-                let palette_bank = match pixel_format {
+                        PixelFormat::BPP4 => entry.palette_bank() as u32,
-                    PixelFormat::BPP4 => entry.palette_bank() as u32,
+                        PixelFormat::BPP8 => 0u32,
-                    PixelFormat::BPP8 => 0u32,
+                    };
-                };
+                    let color = self.get_palette_color(sb, index as u32, palette_bank);
-                let color = self.get_palette_color(sb, index as u32, palette_bank);
+                    self.bg[bg].line[screen_x as usize] = color;
-                if color.get_rgb24() != (0, 0, 0) {
+                    screen_x += 1;
-                    self.pixeldata[index2d!(screen_x as usize, screen_y as usize, 512)] = color;
+                    if (DISPLAY_WIDTH as u32) == screen_x {
-                }
+                        return;
-                screen_x += 1;
+                    }
-                if (Gpu::DISPLAY_WIDTH as u32) == screen_x {
-                    return;
                 }
+                start_tile_x = 0;
+                map_addr += 2;
             }
-            start_tile_x = 0;
+            se_row = 0;
-            if se_row + t == 31 {
+            if bg_width == 512 {
-                if bg_width == 512 {
+                screen_block = screen_block ^ 1;
-                    screen_block = screen_block ^ 1;
-                }
             }
         }
     }
 
-    fn scanline_mode3(&mut self, _bg: u32, sb: &mut SysBus) {
+    fn scanline_aff_bg(&mut self, bg: usize, sb: &mut SysBus) {
+      // TODO
+    }
+
+    fn scanline_mode3(&mut self, bg: usize, sb: &mut SysBus) {
         let y = self.current_scanline;
 
-        for x in 0..Self::DISPLAY_WIDTH {
+        for x in 0..DISPLAY_WIDTH {
-            let pixel_index = index2d!(x, y, Self::DISPLAY_WIDTH);
+            let pixel_index = index2d!(u32, x, y, DISPLAY_WIDTH);
-            let pixel_ofs = 2 * (pixel_index as u32);
+            let pixel_ofs = 2 * pixel_index;
-            self.pixeldata[index2d!(x, y, 512)] = sb.vram.read_16(pixel_ofs).into();
+            let color = Rgb15(sb.vram.read_16(pixel_ofs));
+            self.bg[bg].line[x] = color;
         }
     }
 
-    fn scanline_mode4(&mut self, _bg: u32, sb: &mut SysBus) {
+    fn scanline_mode4(&mut self, bg: usize, sb: &mut SysBus) {
         let page_ofs: u32 = match self.dispcnt.display_frame() {
             0 => 0x0600_0000 - VRAM_ADDR,
             1 => 0x0600_a000 - VRAM_ADDR,
@@ -253,26 +355,43 @@ impl Gpu {
 
         let y = self.current_scanline;
 
-        for x in 0..Self::DISPLAY_WIDTH {
+        for x in 0..DISPLAY_WIDTH {
-            let bitmap_index = index2d!(x, y, Self::DISPLAY_WIDTH);
+            let bitmap_index = index2d!(x, y, DISPLAY_WIDTH);
             let bitmap_ofs = page_ofs + (bitmap_index as u32);
             let index = sb.vram.read_8(bitmap_ofs as Addr) as u32;
-            self.pixeldata[index2d!(x, y, 512)] = self.get_palette_color(sb, index, 0);
+            let color = self.get_palette_color(sb, index, 0);
+            self.bg[bg].line[x] = color;
         }
     }
 
-    pub fn scanline(&mut self, sb: &mut SysBus) {
+    pub fn render_scanline(&mut self, sb: &mut SysBus) {
+        // TODO - also render objs
         match self.dispcnt.mode() {
             BGMode::BGMode0 => {
-                for bg in (0..3).rev() {
+                for bg in 0..3 {
                     if self.dispcnt.disp_bg(bg) {
-                        self.scanline_mode0(bg, sb);
+                        self.scanline_reg_bg(bg, sb);
                     }
                 }
             }
+            BGMode::BGMode1 => {
+                if self.dispcnt.disp_bg(2) {
+                    self.scanline_aff_bg(2, sb);
+                }
+                if self.dispcnt.disp_bg(1) {
+                    self.scanline_reg_bg(1, sb);
+                }
+                if self.dispcnt.disp_bg(0) {
+                    self.scanline_reg_bg(0, sb);
+                }
+            }
             BGMode::BGMode2 => {
-                self.scanline_mode0(3, sb);
+                if self.dispcnt.disp_bg(3) {
-                self.scanline_mode0(2, sb);
+                    self.scanline_aff_bg(3, sb);
+                }
+                if self.dispcnt.disp_bg(2) {
+                    self.scanline_aff_bg(2, sb);
+                }
             }
             BGMode::BGMode3 => {
                 self.scanline_mode3(2, sb);
@@ -282,18 +401,16 @@ impl Gpu {
             }
             _ => panic!("{:?} not supported", self.dispcnt.mode()),
         }
+        self.mosaic_sfx();
+        let post_blend_line = self.blend_line(sb);
+        for x in 0..DISPLAY_WIDTH {
+            self.frame_buffer.0[x + self.current_scanline * DISPLAY_WIDTH] =
+                post_blend_line[x].to_rgb24();
+        }
     }
 
-    pub fn render(&self) -> Vec<u32> {
+    pub fn get_framebuffer(&self) -> &[u32] {
-        let mut buffer = vec![0u32; Gpu::DISPLAY_WIDTH * Gpu::DISPLAY_WIDTH];
+        &self.frame_buffer.0
-        for y in 0..Gpu::DISPLAY_HEIGHT {
-            for x in 0..Gpu::DISPLAY_WIDTH {
-                let (r, g, b) = self.pixeldata[index2d!(x as usize, y as usize, 512)].get_rgb24();
-                buffer[index2d!(x, y, Gpu::DISPLAY_WIDTH)] =
-                    ((r as u32) << 16) | ((g as u32) << 8) | (b as u32);
-            }
-        }
-        buffer
     }
 }
 
@@ -311,12 +428,12 @@ impl SyncedIoDevice for Gpu {
 
         match self.state {
             HDraw => {
-                if self.cycles > Gpu::CYCLES_HDRAW {
+                if self.cycles > CYCLES_HDRAW {
                     self.current_scanline += 1;
-                    self.cycles -= Gpu::CYCLES_HDRAW;
+                    self.cycles -= CYCLES_HDRAW;
 
-                    if self.current_scanline < Gpu::DISPLAY_HEIGHT {
+                    if self.current_scanline < DISPLAY_HEIGHT {
-                        self.scanline(sb);
+                        self.render_scanline(sb);
                         // HBlank
                         self.dispstat.set_hblank(true);
                         if self.dispstat.hblank_irq_enable() {
@@ -324,7 +441,6 @@ impl SyncedIoDevice for Gpu {
                         };
                         self.state = HBlank;
                     } else {
-                        self.scanline(sb);
                         self.dispstat.set_vblank(true);
                         if self.dispstat.vblank_irq_enable() {
                             irqs.set_LCD_VBlank(true);
@@ -334,21 +450,21 @@ impl SyncedIoDevice for Gpu {
                 }
             }
             HBlank => {
-                if self.cycles > Gpu::CYCLES_HBLANK {
+                if self.cycles > CYCLES_HBLANK {
-                    self.cycles -= Gpu::CYCLES_HBLANK;
+                    self.cycles -= CYCLES_HBLANK;
                     self.state = HDraw;
                     self.dispstat.set_hblank(false);
                     self.dispstat.set_vblank(false);
                 }
             }
             VBlank => {
-                if self.cycles > Gpu::CYCLES_VBLANK {
+                if self.cycles > CYCLES_VBLANK {
-                    self.cycles -= Gpu::CYCLES_VBLANK;
+                    self.cycles -= CYCLES_VBLANK;
                     self.state = HDraw;
                     self.dispstat.set_hblank(false);
                     self.dispstat.set_vblank(false);
                     self.current_scanline = 0;
-                    self.scanline(sb);
+                    self.render_scanline(sb);
                 }
             }
         }

src/core/gpu/mosaic.rs

@@ -0,0 +1,35 @@
+use super::*;
+use regs::RegMosaic;
+
+impl RegMosaic {
+    fn is_enabled_for_bg(&self) -> bool {
+        (self.bg_hsize() != 0) || (self.bg_vsize() != 0)
+    }
+}
+
+impl Gpu {
+    fn mosaic_bg(&mut self) {
+        let hsize = (self.mosaic.bg_hsize() + 1) as usize;
+        let vsize = (self.mosaic.bg_vsize() + 1) as usize;
+
+        for bg in 0..4 {
+            if self.dispcnt.disp_bg(bg) && self.bg[bg].bgcnt.mosaic() {
+                let y = self.current_scanline as usize;
+                if y % vsize == 0 {
+                    self.bg[bg].mosaic_first_row = self.bg[bg].line.clone();
+                }
+                for x in 0..DISPLAY_WIDTH {
+                    let color = self.bg[bg].mosaic_first_row[(x / hsize) * hsize];
+                    self.bg[bg].line[x] = color;
+                }
+            }
+        }
+    }
+
+    pub fn mosaic_sfx(&mut self) {
+        if self.mosaic.is_enabled_for_bg() {
+            self.mosaic_bg();
+        }
+        // TODO obj mosaic
+    }
+}

src/core/gpu/regs.rs

@@ -1,23 +1,7 @@
+use super::blend::BldMode;
 use super::*;
 
-bitfield! {
+pub const SCREEN_BLOCK_SIZE: u32 = 0x800;
-    pub struct DisplayControl(u16);
-    impl Debug;
-    u16;
-    pub into BGMode, mode, set_mode: 2, 0;
-    pub display_frame, set_display_frame: 4, 4;
-    pub hblank_interval_free, _: 5;
-    pub obj_character_vram_mapping, _: 6;
-    pub forst_vblank, _: 7;
-    pub disp_bg0, _ : 8;
-    pub disp_bg1, _ : 9;
-    pub disp_bg2, _ : 10;
-    pub disp_bg3, _ : 11;
-    pub disp_obj, _ : 12;
-    pub disp_window0, _ : 13;
-    pub disp_window1, _ : 14;
-    pub disp_obj_window, _ : 15;
-}
 
 impl DisplayControl {
     pub fn disp_bg(&self, bg: usize) -> bool {
@@ -25,35 +9,6 @@ impl DisplayControl {
     }
 }
 
-bitfield! {
-    pub struct DisplayStatus(u16);
-    impl Debug;
-    u16;
-    pub get_vblank, set_vblank: 0;
-    pub get_hblank, set_hblank: 1;
-    pub get_vcount, set_vcount: 2;
-    pub vblank_irq_enable, _ : 3;
-    pub hblank_irq_enable, _ : 4;
-    pub vcount_irq_enable, _ : 5;
-    pub vcount_setting, _ : 15, 8;
-}
-
-bitfield! {
-    #[derive(Copy, Clone)]
-    pub struct BgControl(u16);
-    impl Debug;
-    u16;
-    pub bg_priority, _: 1, 0;
-    pub character_base_block, _: 3, 2;
-    pub moasic, _ : 6;
-    pub palette256, _ : 7;
-    pub screen_base_block, _: 12, 8;
-    pub affine_wraparound, _: 13;
-    pub bg_size, _ : 15, 14;
-}
-
-pub const SCREEN_BLOCK_SIZE: u32 = 0x800;
-
 impl BgControl {
     pub fn char_block(&self) -> u32 {
         VRAM_ADDR + (self.character_base_block() as u32) * 0x4000
@@ -73,11 +28,121 @@ impl BgControl {
         }
     }
 
+    pub fn size_affine(&self) -> (u32, u32) {
+        match self.bg_size() {
+            0b00 => (128, 128),
+            0b01 => (256, 256),
+            0b10 => (512, 512),
+            0b11 => (1024, 1024),
+            _ => unreachable!(),
+        }
+    }
+
     pub fn tile_format(&self) -> (u32, PixelFormat) {
         if self.palette256() {
-            (2 * Gpu::TILE_SIZE, PixelFormat::BPP8)
+            (2 * TILE_SIZE, PixelFormat::BPP8)
         } else {
-            (Gpu::TILE_SIZE, PixelFormat::BPP4)
+            (TILE_SIZE, PixelFormat::BPP4)
         }
     }
 }
+
+// struct definitions below because the bitfield! macro messes up syntax highlighting in vscode.
+bitfield! {
+    pub struct DisplayControl(u16);
+    impl Debug;
+    u16;
+    pub into BGMode, mode, set_mode: 2, 0;
+    pub display_frame, set_display_frame: 4, 4;
+    pub hblank_interval_free, _: 5;
+    pub obj_character_vram_mapping, _: 6;
+    pub forst_vblank, _: 7;
+    pub disp_bg0, _ : 8;
+    pub disp_bg1, _ : 9;
+    pub disp_bg2, _ : 10;
+    pub disp_bg3, _ : 11;
+    pub disp_obj, _ : 12;
+    pub disp_window0, _ : 13;
+    pub disp_window1, _ : 14;
+    pub disp_obj_window, _ : 15;
+}
+
+bitfield! {
+    pub struct DisplayStatus(u16);
+    impl Debug;
+    u16;
+    pub get_vblank, set_vblank: 0;
+    pub get_hblank, set_hblank: 1;
+    pub get_vcount, set_vcount: 2;
+    pub vblank_irq_enable, _ : 3;
+    pub hblank_irq_enable, _ : 4;
+    pub vcount_irq_enable, _ : 5;
+    pub vcount_setting, _ : 15, 8;
+}
+
+bitfield! {
+    #[derive(Default, Copy, Clone)]
+    pub struct BgControl(u16);
+    impl Debug;
+    u16;
+    pub priority, _: 1, 0;
+    pub character_base_block, _: 3, 2;
+    pub mosaic, _ : 6;
+    pub palette256, _ : 7;
+    pub screen_base_block, _: 12, 8;
+    pub affine_wraparound, _: 13;
+    pub bg_size, _ : 15, 14;
+}
+
+bitfield! {
+    #[derive(Default, Copy, Clone)]
+    pub struct RegMosaic(u16);
+    impl Debug;
+    u32;
+    pub bg_hsize, _: 3, 0;
+    pub bg_vsize, _: 7, 4;
+    pub obj_hsize, _ : 11, 8;
+    pub obj_vsize, _ : 15, 12;
+}
+
+bitflags! {
+    pub struct BlendFlags: u32 {
+        const BG0 = 0b00000001;
+        const BG1 = 0b00000010;
+        const BG2 = 0b00000100;
+        const BG3 = 0b00001000;
+        const OBJ = 0b00010000;
+        const BACKDROP  = 0b00100000; // BACKDROP
+    }
+}
+
+impl From<u16> for BlendFlags {
+    fn from(v: u16) -> BlendFlags {
+        BlendFlags::from_bits(v as u32).unwrap()
+    }
+}
+
+pub const BG_LAYER_FLAG: [BlendFlags; 4] = [
+    BlendFlags::BG0,
+    BlendFlags::BG1,
+    BlendFlags::BG2,
+    BlendFlags::BG3,
+];
+
+bitfield! {
+    #[derive(Default, Copy, Clone)]
+    pub struct BlendControl(u16);
+    impl Debug;
+    pub into BlendFlags, top, _: 5, 0;
+    pub into BldMode, mode, set_mode: 7, 6;
+    pub into BlendFlags, bottom, _: 13, 8;
+}
+
+bitfield! {
+    #[derive(Default, Copy, Clone)]
+    pub struct BlendAlpha(u16);
+    impl Debug;
+    u16;
+    pub eva, _: 5, 0;
+    pub evb, _: 12, 8;
+}

src/core/interrupt.rs

@@ -1,5 +1,3 @@
-use super::arm7tdmi::Core;
-
 #[derive(Debug, Primitive, Copy, Clone, PartialEq)]
 #[allow(non_camel_case_types)]
 pub enum Interrupt {
@@ -54,22 +52,35 @@ impl IrqBitmask {
 
 bitfield! {
     #[derive(Default, Copy, Clone, PartialEq)]
-    #[allow(non_snake_case)]
     pub struct IrqBitmask(u16);
     impl Debug;
     u16;
+    #[allow(non_snake_case)]
     pub LCD_VBlank, set_LCD_VBlank: 0;
+    #[allow(non_snake_case)]
     pub LCD_HBlank, set_LCD_HBlank: 1;
+    #[allow(non_snake_case)]
     pub LCD_VCounterMatch, set_LCD_VCounterMatch: 2;
+    #[allow(non_snake_case)]
     pub Timer0_Overflow, set_Timer0_Overflow: 3;
+    #[allow(non_snake_case)]
     pub Timer1_Overflow, set_Timer1_Overflow: 4;
+    #[allow(non_snake_case)]
     pub Timer2_Overflow, set_Timer2_Overflow: 5;
+    #[allow(non_snake_case)]
     pub Timer3_Overflow, set_Timer3_Overflow: 6;
+    #[allow(non_snake_case)]
     pub SerialCommunication, set_SerialCommunication: 7;
+    #[allow(non_snake_case)]
     pub DMA0, set_DMA0: 8;
+    #[allow(non_snake_case)]
     pub DMA1, set_DMA1: 9;
+    #[allow(non_snake_case)]
     pub DMA2, set_DMA2: 10;
+    #[allow(non_snake_case)]
     pub DMA3, set_DMA3: 11;
+    #[allow(non_snake_case)]
     pub Keypad, set_Keypad: 12;
+    #[allow(non_snake_case)]
     pub GamePak, set_GamePak: 13;
 }

src/core/ioregs.rs

@@ -31,14 +31,18 @@ pub mod consts {
     pub const REG_BG2PB: Addr = IO_BASE + 0x_0022; //  2    W         BG2 Rotation/Scaling Parameter B (dmx)
     pub const REG_BG2PC: Addr = IO_BASE + 0x_0024; //  2    W         BG2 Rotation/Scaling Parameter C (dy)
     pub const REG_BG2PD: Addr = IO_BASE + 0x_0026; //  2    W         BG2 Rotation/Scaling Parameter D (dmy)
-    pub const REG_BG2X: Addr = IO_BASE + 0x_0028; //  4    W          BG2 Reference Point X-Coordinate
+    pub const REG_BG2X_L: Addr = IO_BASE + 0x_0028; //  4    W          BG2 Reference Point X-Coordinate, lower 16 bit
-    pub const REG_BG2Y: Addr = IO_BASE + 0x_002C; //  4    W          BG2 Reference Point Y-Coordinate
+    pub const REG_BG2X_H: Addr = IO_BASE + 0x_002A; //  4    W          BG2 Reference Point X-Coordinate, upper 16 bit
+    pub const REG_BG2Y_L: Addr = IO_BASE + 0x_002C; //  4    W          BG2 Reference Point Y-Coordinate, lower 16 bit
+    pub const REG_BG2Y_H: Addr = IO_BASE + 0x_002E; //  4    W          BG2 Reference Point Y-Coordinate, upper 16 bit
     pub const REG_BG3PA: Addr = IO_BASE + 0x_0030; //  2    W         BG3 Rotation/Scaling Parameter A (dx)
     pub const REG_BG3PB: Addr = IO_BASE + 0x_0032; //  2    W         BG3 Rotation/Scaling Parameter B (dmx)
     pub const REG_BG3PC: Addr = IO_BASE + 0x_0034; //  2    W         BG3 Rotation/Scaling Parameter C (dy)
     pub const REG_BG3PD: Addr = IO_BASE + 0x_0036; //  2    W         BG3 Rotation/Scaling Parameter D (dmy)
-    pub const REG_BG3X: Addr = IO_BASE + 0x_0038; //  4    W          BG3 Reference Point X-Coordinate
+    pub const REG_BG3X_L: Addr = IO_BASE + 0x_0038; //  4    W          BG3 Reference Point X-Coordinate, lower 16 bit
-    pub const REG_BG3Y: Addr = IO_BASE + 0x_003C; //  4    W          BG3 Reference Point Y-Coordinate
+    pub const REG_BG3X_H: Addr = IO_BASE + 0x_003A; //  4    W          BG3 Reference Point X-Coordinate, upper 16 bit
+    pub const REG_BG3Y_L: Addr = IO_BASE + 0x_003C; //  4    W          BG3 Reference Point Y-Coordinate, lower 16 bit
+    pub const REG_BG3Y_H: Addr = IO_BASE + 0x_003E; //  4    W          BG3 Reference Point Y-Coordinate, upper 16 bit
     pub const REG_WIN0H: Addr = IO_BASE + 0x_0040; //  2    W         Window 0 Horizontal Dimensions
     pub const REG_WIN1H: Addr = IO_BASE + 0x_0042; //  2    W         Window 1 Horizontal Dimensions
     pub const REG_WIN0V: Addr = IO_BASE + 0x_0044; //  2    W         Window 0 Vertical Dimensions
@@ -155,20 +159,18 @@ impl Bus for IoRegs {
             REG_DISPCNT => io.gpu.dispcnt.0,
             REG_DISPSTAT => io.gpu.dispstat.0,
             REG_VCOUNT => io.gpu.current_scanline as u16,
-            REG_BG0CNT => io.gpu.bgcnt[0].0,
+            REG_BG0CNT => io.gpu.bg[0].bgcnt.0,
-            REG_BG1CNT => io.gpu.bgcnt[1].0,
+            REG_BG1CNT => io.gpu.bg[1].bgcnt.0,
-            REG_BG2CNT => io.gpu.bgcnt[2].0,
+            REG_BG2CNT => io.gpu.bg[2].bgcnt.0,
-            REG_BG3CNT => io.gpu.bgcnt[3].0,
+            REG_BG3CNT => io.gpu.bg[3].bgcnt.0,
             REG_WIN0H => io.gpu.win0h,
             REG_WIN1H => io.gpu.win1h,
             REG_WIN0V => io.gpu.win0v,
             REG_WIN1V => io.gpu.win1v,
             REG_WININ => io.gpu.winin,
             REG_WINOUT => io.gpu.winout,
-            REG_MOSAIC => io.gpu.mosaic,
+            REG_BLDCNT => io.gpu.bldcnt.0,
-            REG_BLDCNT => io.gpu.bldcnt,
+            REG_BLDALPHA => io.gpu.bldalpha.0,
-            REG_BLDALPHA => io.gpu.bldalpha,
-            REG_BLDY => io.gpu.bldy,
 
             REG_IME => io.intc.interrupt_master_enable as u16,
             REG_IE => io.intc.interrupt_enable.0 as u16,
@@ -206,28 +208,44 @@ impl Bus for IoRegs {
         match addr + IO_BASE {
             REG_DISPCNT => io.gpu.dispcnt.0 |= value,
             REG_DISPSTAT => io.gpu.dispstat.0 |= value,
-            REG_BG0CNT => io.gpu.bgcnt[0].0 |= value,
+            REG_BG0CNT => io.gpu.bg[0].bgcnt.0 |= value,
-            REG_BG1CNT => io.gpu.bgcnt[1].0 |= value,
+            REG_BG1CNT => io.gpu.bg[1].bgcnt.0 |= value,
-            REG_BG2CNT => io.gpu.bgcnt[2].0 |= value,
+            REG_BG2CNT => io.gpu.bg[2].bgcnt.0 |= value,
-            REG_BG3CNT => io.gpu.bgcnt[3].0 |= value,
+            REG_BG3CNT => io.gpu.bg[3].bgcnt.0 |= value,
-            REG_BG0HOFS => io.gpu.bghofs[0] = value,
+            REG_BG0HOFS => io.gpu.bg[0].bghofs = value & 0x1ff,
-            REG_BG0VOFS => io.gpu.bgvofs[0] = value,
+            REG_BG0VOFS => io.gpu.bg[0].bgvofs = value & 0x1ff,
-            REG_BG1HOFS => io.gpu.bghofs[1] = value,
+            REG_BG1HOFS => io.gpu.bg[1].bghofs = value & 0x1ff,
-            REG_BG1VOFS => io.gpu.bgvofs[1] = value,
+            REG_BG1VOFS => io.gpu.bg[1].bgvofs = value & 0x1ff,
-            REG_BG2HOFS => io.gpu.bghofs[2] = value,
+            REG_BG2HOFS => io.gpu.bg[2].bghofs = value & 0x1ff,
-            REG_BG2VOFS => io.gpu.bgvofs[2] = value,
+            REG_BG2VOFS => io.gpu.bg[2].bgvofs = value & 0x1ff,
-            REG_BG3HOFS => io.gpu.bghofs[3] = value,
+            REG_BG3HOFS => io.gpu.bg[3].bghofs = value & 0x1ff,
-            REG_BG3VOFS => io.gpu.bgvofs[3] = value,
+            REG_BG3VOFS => io.gpu.bg[3].bgvofs = value & 0x1ff,
+            REG_BG2X_L => io.gpu.bg_aff[0].x |= (value as u32) as i32,
+            REG_BG2X_H => io.gpu.bg_aff[0].x |= ((value as u32) << 16) as i32,
+            REG_BG2Y_L => io.gpu.bg_aff[0].y |= (value as u32) as i32,
+            REG_BG2Y_H => io.gpu.bg_aff[0].y |= ((value as u32) << 16) as i32,
+            REG_BG3X_L => io.gpu.bg_aff[1].x |= (value as u32) as i32,
+            REG_BG3X_H => io.gpu.bg_aff[1].x |= ((value as u32) << 16) as i32,
+            REG_BG3Y_L => io.gpu.bg_aff[1].y |= (value as u32) as i32,
+            REG_BG3Y_H => io.gpu.bg_aff[1].y |= ((value as u32) << 16) as i32,
+            REG_BG2PA => io.gpu.bg_aff[0].pa = value as i16,
+            REG_BG2PB => io.gpu.bg_aff[0].pb = value as i16,
+            REG_BG2PC => io.gpu.bg_aff[0].pc = value as i16,
+            REG_BG2PD => io.gpu.bg_aff[0].pd = value as i16,
+            REG_BG3PA => io.gpu.bg_aff[1].pa = value as i16,
+            REG_BG3PB => io.gpu.bg_aff[1].pb = value as i16,
+            REG_BG3PC => io.gpu.bg_aff[1].pc = value as i16,
+            REG_BG3PD => io.gpu.bg_aff[1].pd = value as i16,
             REG_WIN0H => io.gpu.win0h = value,
             REG_WIN1H => io.gpu.win1h = value,
             REG_WIN0V => io.gpu.win0v = value,
             REG_WIN1V => io.gpu.win1v = value,
             REG_WININ => io.gpu.winin = value,
             REG_WINOUT => io.gpu.winout = value,
-            REG_MOSAIC => io.gpu.mosaic = value,
+            REG_MOSAIC => io.gpu.mosaic.0 = value,
-            REG_BLDCNT => io.gpu.bldcnt = value,
+            REG_BLDCNT => io.gpu.bldcnt.0 = value,
-            REG_BLDALPHA => io.gpu.bldalpha = value,
+            REG_BLDALPHA => io.gpu.bldalpha.0 = value,
-            REG_BLDY => io.gpu.bldy = value,
+            REG_BLDY => io.gpu.bldy = value & 0b11111,
 
             REG_IME => io.intc.interrupt_master_enable = value != 0,
             REG_IE => io.intc.interrupt_enable.0 = value,

src/core/timer.rs

@@ -114,7 +114,6 @@ impl SyncedIoDevice for Timers {
                         }
                     }
                     TimerAction::Increment => {}
-                    _ => {}
                 }
             }
         }

src/debugger/tile_view.rs

@@ -6,14 +6,7 @@ use sdl2::rect::{Point, Rect};
 use sdl2::render::Canvas;
 
 use crate::core::gba::GameBoyAdvance;
-use crate::core::palette::*;
+use crate::core::gpu::PixelFormat;
-
-impl Into<Color> for Rgb15 {
-    fn into(self) -> Color {
-        let (r, g, b) = self.get_rgb24();
-        Color::RGB(r, g, b)
-    }
-}
 
 fn draw_tile(
     gba: &GameBoyAdvance,
@@ -29,9 +22,11 @@ fn draw_tile(
                 .gpu
                 .read_pixel_index(&gba.sysbus, tile_addr, x, y, pixel_format);
             let color = io.gpu.get_palette_color(&gba.sysbus, index as u32, 0);
-            let (r, g, b) = color.get_rgb24();
+            canvas.set_draw_color(Color::RGB(
-
+                (color.r() as u8) << 3,
-            canvas.set_draw_color(Color::RGB(r, g, b));
+                (color.g() as u8) << 3,
+                (color.b() as u8) << 3,
+            ));
             canvas.draw_point(p.offset(x as i32, y as i32)).unwrap();
         }
     }
@@ -52,7 +47,7 @@ pub fn create_tile_view(bg: u32, gba: &GameBoyAdvance) {
 
     let mut canvas = window.into_canvas().build().unwrap();
 
-    let bgcnt = gba.io.borrow().gpu.bgcnt[bg as usize].clone();
+    let bgcnt = gba.io.borrow().gpu.bg[bg as usize].bgcnt.clone();
 
     let (tile_size, pixel_format) = bgcnt.tile_format();
     let tileset_addr = bgcnt.char_block();

src/lib.rs

@@ -6,6 +6,8 @@ extern crate num_traits;
 extern crate bit;
 #[macro_use]
 extern crate bitfield;
+#[macro_use]
+extern crate bitflags;
 
 extern crate byteorder;
 

src/util.rs

@@ -14,4 +14,7 @@ macro_rules! index2d {
     ($x:expr, $y:expr, $w:expr) => {
         $w * $y + $x
     };
+    ($t:ty, $x:expr, $y:expr, $w:expr) => {
+        (($w as $t) * ($y as $t) + ($x as $t)) as $t
+    };
 }