WIP mode0 rendering

Former-commit-id: 6bce375f9373bbddf4522da5ecc2ea3584373847

Cargo.lock

@@ -566,6 +566,7 @@ dependencies = [
  "num-traits 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)",
  "rustyline 5.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "sdl2 0.32.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -719,6 +720,16 @@ dependencies = [
  "unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "time"
+version = "0.1.42"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.58 (registry+https://github.com/rust-lang/crates.io-index)",
+ "redox_syscall 0.1.54 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "unicode-segmentation"
 version = "1.3.0"
@@ -887,6 +898,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 "checksum synstructure 0.10.2 (registry+https://github.com/rust-lang/crates.io-index)" = "02353edf96d6e4dc81aea2d8490a7e9db177bf8acb0e951c24940bf866cb313f"
 "checksum termion 1.5.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6a8fb22f7cde82c8220e5aeacb3258ed7ce996142c77cba193f203515e26c330"
 "checksum textwrap 0.11.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d326610f408c7a4eb6f51c37c330e496b08506c9457c9d34287ecc38809fb060"
+"checksum time 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)" = "db8dcfca086c1143c9270ac42a2bbd8a7ee477b78ac8e45b19abfb0cbede4b6f"
 "checksum unicode-segmentation 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "1967f4cdfc355b37fd76d2a954fb2ed3871034eb4f26d60537d88795cfc332a9"
 "checksum unicode-width 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "882386231c45df4700b275c7ff55b6f3698780a650026380e72dabe76fa46526"
 "checksum unicode-xid 0.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "8c1f860d7d29cf02cb2f3f359fd35991af3d30bac52c57d265a3c461074cb4dc"

Cargo.toml

@@ -17,6 +17,8 @@ colored = "1.8"
 ansi_term = "0.11.0"
 hexdump = "0.1.0"
 sdl2 = "0.32.2"
+time = "0.1.42"
 
 [profile.dev]
-opt-level = 0
+opt-level = 1
+debug = true

src/debugger/command.rs

@@ -6,6 +6,8 @@ use crate::lcd::*;
 use crate::GBAError;
 
 use super::palette_view::create_palette_view;
+use super::render_view::create_render_view;
+use super::tile_view::create_tile_view;
 use super::{parser::Value, Debugger, DebuggerError, DebuggerResult};
 
 use ansi_term::Colour;
@@ -26,11 +28,13 @@ pub enum Command {
     Step(usize),
     Continue,
     Frame(usize),
+    Render,
     HexDump(Addr, usize),
     Disass(DisassMode, Addr, usize),
     AddBreakpoint(Addr),
     DelBreakpoint(Addr),
     PaletteView,
+    TileView(u32),
     ClearBreakpoints,
     ListBreakpoints,
     Reset,
@@ -43,7 +47,6 @@ impl Command {
         match *self {
             Info => println!("{}", debugger.gba.cpu),
             DisplayInfo => {
-                println!("{:?}", debugger.gba.lcd);
                 println!(
                     "DISPCNT: {:#?}",
                     DisplayControl::from(debugger.gba.sysbus.ioregs.read_reg(REG_DISPCNT))
@@ -56,6 +59,11 @@ impl Command {
                     "VCOUNT: {:?}",
                     debugger.gba.sysbus.ioregs.read_reg(REG_VCOUNT)
                 );
+                for bg in 0..4 {
+                    let bgcnt =
+                        BgControl::from(debugger.gba.sysbus.ioregs.read_reg(REG_BG0CNT + 2 * bg));
+                    println!("BG{}CNT: {:#?}", bg, bgcnt);
+                }
             }
             Step(count) => {
                 for _ in 0..count {
@@ -115,11 +123,15 @@ impl Command {
                 };
             },
             Frame(count) => {
+                use super::time::PreciseTime;
+                let start = PreciseTime::now();
                 for _ in 0..count {
                     debugger.gba.frame();
-                    print!(".")
                 }
+                let end = PreciseTime::now();
+                println!("that took {} seconds", start.to(end));
             }
+            Render => create_render_view(&debugger.gba),
             HexDump(addr, nbytes) => {
                 let bytes = debugger.gba.sysbus.get_bytes(addr);
                 hexdump::hexdump(&bytes[0..nbytes]);
@@ -166,6 +178,7 @@ impl Command {
                 }
             }
             PaletteView => create_palette_view(debugger.gba.sysbus.get_bytes(0x0500_0000)),
+            TileView(bg) => create_tile_view(bg, &debugger.gba),
             Reset => {
                 println!("resetting cpu...");
                 debugger.gba.cpu.reset();
@@ -308,9 +321,17 @@ impl Debugger {
                 ))),
             },
             "palette-view" => Ok(Command::PaletteView),
+            "tiles" => {
+                if args.len() != 1 {
+                    return Err(DebuggerError::InvalidCommandFormat("tile <bg>".to_string()));
+                }
+                let bg = self.val_number(&args[0])?;
+                Ok(Command::TileView(bg))
+            }
             "bl" => Ok(Command::ListBreakpoints),
             "q" | "quit" => Ok(Command::Quit),
             "r" | "reset" => Ok(Command::Reset),
+            "rd" | "render" => Ok(Command::Render),
             _ => Err(DebuggerError::InvalidCommand(command)),
         }
     }

src/debugger/mod.rs

@@ -13,6 +13,9 @@ mod command;
 use command::Command;
 
 mod palette_view;
+mod render_view;
+mod tile_view;
+extern crate time;
 
 #[derive(Debug, PartialEq)]
 pub enum DebuggerError {
@@ -31,7 +34,6 @@ impl From<CpuError> for DebuggerError {
 
 type DebuggerResult<T> = Result<T, DebuggerError>;
 
-#[derive(Debug)]
 pub struct Debugger {
     pub gba: GameBoyAdvance,
     running: bool,

src/debugger/render_view.rs

@@ -0,0 +1,50 @@
+use sdl2::event::Event;
+use sdl2::pixels::Color;
+use sdl2::rect::Point;
+
+use crate::gba::GameBoyAdvance;
+use crate::lcd::Lcd;
+
+const SCREEN_WIDTH: u32 = Lcd::DISPLAY_WIDTH as u32;
+const SCREEN_HEIGHT: u32 = Lcd::DISPLAY_HEIGHT as u32;
+
+pub fn create_render_view(gba: &GameBoyAdvance) {
+    let sdl_context = sdl2::init().unwrap();
+    let video_subsystem = sdl_context.video().unwrap();
+
+    let window = video_subsystem
+        .window("RenderView", SCREEN_WIDTH, SCREEN_HEIGHT)
+        .position_centered()
+        .build()
+        .unwrap();
+
+    let mut canvas = window.into_canvas().build().unwrap();
+
+    canvas.set_draw_color(Color::RGB(0xfa, 0xfa, 0xfa));
+    canvas.clear();
+
+    for y in 0..Lcd::DISPLAY_HEIGHT {
+        for x in 0..Lcd::DISPLAY_WIDTH {
+            let index = (x as usize) + (y as usize) * (256 as usize);
+            let color = gba.lcd.pixeldata[index];
+            let rgb24: Color = color.into();
+            canvas.set_draw_color(rgb24);
+            canvas.draw_point(Point::from((x as i32, y as i32)));
+        }
+    }
+
+    canvas.present();
+
+    let mut event_pump = sdl_context.event_pump().unwrap();
+    'running: loop {
+        for event in event_pump.poll_iter() {
+            match event {
+                Event::Quit { .. } => break 'running,
+                Event::MouseButtonDown { x, y, .. } => {
+                    println!("({},{}) {:x}", x, y, x + y * (Lcd::DISPLAY_WIDTH as i32));
+                }
+                _ => {}
+            }
+        }
+    }
+}

src/debugger/tile_view.rs

@@ -0,0 +1,105 @@
+use sdl2::event::Event;
+use sdl2::pixels::Color;
+use sdl2::rect::{Point, Rect};
+use sdl2::render::Canvas;
+
+use crate::arm7tdmi::bus::Bus;
+use crate::gba::GameBoyAdvance;
+use crate::ioregs::consts::*;
+use crate::lcd::*;
+use crate::palette::*;
+use crate::sysbus::SysBus;
+
+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,
+    tile_addr: u32,
+    pixel_format: PixelFormat,
+    p: Point,
+    canvas: &mut Canvas<sdl2::video::Window>,
+) {
+    for y in 0..8 {
+        for x in 0..8 {
+            let color = match pixel_format {
+                PixelFormat::BPP4 => {
+                    let index =
+                        gba.lcd
+                            .read_pixel_index(&gba.sysbus, tile_addr, x, y, 4, pixel_format);
+                    gba.lcd.get_palette_color(&gba.sysbus, index as u32, 0)
+                }
+                PixelFormat::BPP8 => {
+                    let index =
+                        gba.lcd
+                            .read_pixel_index(&gba.sysbus, tile_addr, x, y, 8, pixel_format);
+                    gba.lcd.get_palette_color(&gba.sysbus, index as u32, 0)
+                }
+            };
+            let (r, g, b) = color.get_rgb24();
+
+            canvas.set_draw_color(Color::RGB(r, g, b));
+            canvas.draw_point(p.offset(x as i32, y as i32));
+        }
+    }
+}
+
+pub fn create_tile_view(bg: u32, gba: &GameBoyAdvance) {
+    let sdl_context = sdl2::init().unwrap();
+    let video_subsystem = sdl_context.video().unwrap();
+
+    let window = video_subsystem
+        .window("PaletteView", 512, 512)
+        .position_centered()
+        .build()
+        .unwrap();
+
+    let mut canvas = window.into_canvas().build().unwrap();
+
+    canvas.set_draw_color(Color::RGB(00, 00, 00));
+    canvas.clear();
+
+    let bgcnt = BgControl::from(gba.sysbus.ioregs.read_reg(REG_BG0CNT + 2 * bg));
+
+    let palette = Palette::from(gba.sysbus.get_bytes(0x0500_0000));
+    let (tile_size, pixel_format) = bgcnt.tile_format();
+    let tileset_addr = bgcnt.char_block();
+    let tilemap_addr = bgcnt.screen_block();
+    let tiles_per_row = 32;
+    let num_tiles = 0x4000 / tile_size;
+    println!("tileset: {:#x}, tilemap: {:#x}", tileset_addr, tilemap_addr);
+
+    let mut tile_x = 0x20;
+    let mut tile_y = 0x20;
+    for t in 0..num_tiles {
+        let tile_addr = tileset_addr + t * tile_size;
+        if t != 0 && t % tiles_per_row == 0 {
+            tile_y += 10;
+            tile_x = 0x20;
+        }
+        tile_x += 10;
+        draw_tile(
+            gba,
+            tile_addr,
+            pixel_format,
+            Point::from((tile_x, tile_y)),
+            &mut canvas,
+        );
+    }
+
+    canvas.present();
+
+    let mut event_pump = sdl_context.event_pump().unwrap();
+    'running: loop {
+        for event in event_pump.poll_iter() {
+            match event {
+                Event::Quit { .. } => break 'running,
+                _ => {}
+            }
+        }
+    }
+}

src/gba.rs

@@ -1,15 +1,15 @@
 /// Struct containing everything
 ///
-use super::arm7tdmi::{Core, DecodedInstruction};
+use super::arm7tdmi::{exception::*, Core, DecodedInstruction};
 use super::cartridge::Cartridge;
 use super::dma::DmaChannel;
+use super::interrupt::*;
 use super::ioregs::consts::*;
-use super::lcd::Lcd;
+use super::lcd::*;
 use super::sysbus::SysBus;
 
-use super::{EmuIoDev, GBAResult};
+use super::{EmuIoDev, GBAError, GBAResult};
 
-#[derive(Debug)]
 pub struct GameBoyAdvance {
     pub cpu: Core,
     pub sysbus: SysBus,
@@ -42,26 +42,52 @@ impl GameBoyAdvance {
         }
     }
 
-    fn run_cpu_for_n_cycles(&mut self, n: usize) {
+    fn emulate_n_cycles(&mut self, mut n: usize) {
-        let previous_cycles = self.cpu.cycles;
+        let mut cycles = 0;
         loop {
+            let previous_cycles = self.cpu.cycles;
             self.cpu.step_one(&mut self.sysbus).unwrap();
-            if n > self.cpu.cycles - previous_cycles {
+            let new_cycles = self.cpu.cycles - previous_cycles;
+
+            self.lcd.step(new_cycles, &mut self.sysbus);
+            cycles += new_cycles;
+
+            if n <= cycles {
                 break;
             }
         }
     }
 
     pub fn frame(&mut self) {
-        for _ in 0..Lcd::DISPLAY_HEIGHT {
+        while self.lcd.state == LcdState::VBlank {
-            self.run_cpu_for_n_cycles(Lcd::CYCLES_HDRAW);
+            self.emulate();
-            let _irq = self.lcd.set_hblank(&mut self.sysbus);
-            self.run_cpu_for_n_cycles(Lcd::CYCLES_HBLANK);
         }
-        let _irq = self.lcd.set_vblank(&mut self.sysbus);
+        while self.lcd.state != LcdState::VBlank {
-        self.run_cpu_for_n_cycles(Lcd::CYCLES_VBLANK);
+            self.emulate();
-        self.lcd.render(&mut self.sysbus); // Currently not implemented
+        }
-        self.lcd.set_hdraw();
+    }
+
+    pub fn emulate(&mut self) {
+        let previous_cycles = self.cpu.cycles;
+        self.cpu.step(&mut self.sysbus).unwrap();
+        let cycles = self.cpu.cycles - previous_cycles;
+        self.lcd.step(cycles, &mut self.sysbus);
+    }
+
+    fn interrupts_disabled(&self) -> bool {
+        self.sysbus.ioregs.read_reg(REG_IME) & 1 == 0
+    }
+
+    fn request_irq(&mut self, irq: Interrupt) {
+        // if self.interrupts_disabled() {
+        //     return;
+        // }
+        // let irq_bit = irq as usize;
+        // let reg_ie = self.sysbus.ioregs.read_reg(REG_IE);
+        // if reg_ie & (1 << irq_bit) != 0 {
+        //     println!("entering {:?}", irq);
+        //     self.cpu.exception(Exception::Irq);
+        // }
     }
 
     pub fn step(&mut self) -> GBAResult<DecodedInstruction> {
@@ -84,7 +110,11 @@ impl GameBoyAdvance {
         // let (dma_cycles, _) = self.dma3.step(cycles, &mut self.sysbus);
         // cycles += dma_cycles;
 
-        // let (lcd_cycles, _) = self.lcd.step(cycles, &mut self.sysbus);
+        /* let (_, irq) = */
+        self.lcd.step(cycles, &mut self.sysbus);
+        // if let Some(irq) = irq {
+        //     self.request_irq(irq);
+        // }
         // cycles += lcd_cycles;
 
         Ok(executed_insn)

src/lcd.rs

@@ -1,11 +1,17 @@
-use super::arm7tdmi::Bus;
+use std::io::Cursor;
+use std::io::{Seek, SeekFrom};
+
+use super::arm7tdmi::{Addr, Bus};
 use super::ioregs::consts::*;
-use super::palette::{Palette, Rgb15};
+use super::palette::{Palette, PixelFormat, Rgb15};
 use super::*;
 
 use crate::bit::BitIndex;
+use crate::byteorder::{LittleEndian, ReadBytesExt};
 use crate::num::FromPrimitive;
 
+const VRAM_ADDR: Addr = 0x0600_0000;
+
 #[derive(Debug, Primitive)]
 enum BGMode {
     BGMode0 = 0,
@@ -81,7 +87,7 @@ pub struct BgControl {
     bg_priority: u8,
     character_base_block: u8,
     moasic: bool,
-    colors_palettes: bool, // 0=16/16, 1=256/1)
+    palette256: bool, // 0=16/16, 1=256/1)
     screen_base_block: u8,
     wraparound: bool,
     screen_width: usize,
@@ -99,9 +105,9 @@ impl From<u16> for BgControl {
         };
         BgControl {
             bg_priority: v.bit_range(0..2) as u8,
-            character_base_block: v.bit_range(2..3) as u8,
+            character_base_block: v.bit_range(2..4) as u8,
             moasic: v.bit(6),
-            colors_palettes: v.bit(7), // 0=16/16, 1=256/1)
+            palette256: v.bit(7),
             screen_base_block: v.bit_range(8..13) as u8,
             wraparound: v.bit(13),
             screen_width: width,
@@ -110,6 +116,24 @@ impl From<u16> for BgControl {
     }
 }
 
+impl BgControl {
+    pub fn char_block(&self) -> Addr {
+        VRAM_ADDR + (self.character_base_block as u32) * 0x4000
+    }
+
+    pub fn screen_block(&self) -> Addr {
+        VRAM_ADDR + (self.screen_base_block as u32) * 0x800
+    }
+
+    pub fn tile_format(&self) -> (u32, PixelFormat) {
+        if self.palette256 {
+            (2 * Lcd::TILE_SIZE, PixelFormat::BPP8)
+        } else {
+            (Lcd::TILE_SIZE, PixelFormat::BPP4)
+        }
+    }
+}
+
 #[derive(Debug, PartialEq, Copy, Clone)]
 pub enum LcdState {
     HDraw = 0,
@@ -123,11 +147,11 @@ impl Default for LcdState {
 }
 use LcdState::*;
 
-#[derive(Debug, Default)]
 pub struct Lcd {
     cycles: usize,
-    state: LcdState,
+    pub pixeldata: [Rgb15; 256 * 256],
-    current_scanline: usize, // VCOUNT
+    pub state: LcdState,
+    pub current_scanline: usize, // VCOUNT
 }
 
 impl Lcd {
@@ -141,10 +165,14 @@ impl Lcd {
     pub const CYCLES_VDRAW: usize = 197120;
     pub const CYCLES_VBLANK: usize = 83776;
 
+    pub const TILE_SIZE: u32 = 0x20;
+
     pub fn new() -> Lcd {
         Lcd {
             state: HDraw,
-            ..Default::default()
+            current_scanline: 0,
+            cycles: 0,
+            pixeldata: [Rgb15::from(0); 256 * 256],
         }
     }
 
@@ -179,7 +207,7 @@ impl Lcd {
         let mut v = dispstat.raw_value;
         v.set_bit(1, false);
         v.set_bit(0, true);
-        self.state = HBlank;
+        self.state = VBlank;
         sysbus.ioregs.write_reg(REG_DISPSTAT, v);
 
         if dispstat.vblank_irq_enable {
@@ -193,88 +221,206 @@ impl Lcd {
         self.state = HDraw;
     }
 
-    fn bgcnt(&self, sysbus: &SysBus, bg: u32) -> BgControl {
+    fn bgcnt(&self, bg: u32, sysbus: &SysBus) -> BgControl {
         BgControl::from(sysbus.ioregs.read_reg(REG_BG0CNT + 2 * bg))
     }
 
-    pub fn render(&mut self, sysbus: &SysBus) {
+    fn bgofs(&self, bg: u32, sysbus: &SysBus) -> (u32, u32) {
-        // let dispcnt = DisplayControl::from(sysbus.ioregs.read_reg(REG_DISPCNT));
+        let hofs = (sysbus.ioregs.read_reg(REG_BG0HOFS + 4 * bg) & 0x1ff) as u32;
-        // let dispstat = DisplayStatus::from(sysbus.ioregs.read_reg(REG_DISPSTAT));
+        let vofs = (sysbus.ioregs.read_reg(REG_BG0VOFS + 4 * bg) & 0x1ff) as u32;
+        (hofs, vofs)
+    }
 
-        // TODO - redner
+    /// helper method that reads the palette index from a base address and x + y
+    pub fn read_pixel_index(
+        &self,
+        sysbus: &SysBus,
+        addr: Addr,
+        x: u32,
+        y: u32,
+        width: u32,
+        format: PixelFormat,
+    ) -> usize {
+        match format {
+            PixelFormat::BPP4 => {
+                let byte = sysbus.read_8(addr + width * y + x / 2);
+                if x & 1 != 0 {
+                    (byte >> 4) as usize
+                } else {
+                    (byte & 0xf) as usize
+                }
+            }
+            PixelFormat::BPP8 => sysbus.read_8(addr + width * y + x) as usize,
+        }
+    }
+
+    pub fn get_palette_color(&self, sysbus: &SysBus, index: u32, palette_index: u32) -> Rgb15 {
+        sysbus
+            .read_16(0x0500_0000 + 2 * index + 0x20 * palette_index)
+            .into()
+    }
+
+    fn scanline_mode0(&mut self, bg: u32, sysbus: &mut SysBus) {
+        let bgcnt = self.bgcnt(bg, sysbus);
+        let tileset_base = bgcnt.char_block();
+        let tilemap_base = bgcnt.screen_block();
+        let (tile_size, pixel_format) = bgcnt.tile_format();
+
+        let tiles_per_row = bgcnt.screen_width / 8;
+
+        let mut px = 0;
+        let py = self.current_scanline;
+        let tile_y = py % 8;
+
+        for tile in 0..tiles_per_row {
+            let tile_y = py % 8;
+
+            let map_addr = tilemap_base + (tile as u32) * 2;
+            let entry = TileMapEntry::from(sysbus.read_16(map_addr));
+            let tile_addr = tileset_base + entry.tile_index * tile_size;
+
+            for tile_x in 0..=7 {
+                let color = match pixel_format {
+                    PixelFormat::BPP4 => {
+                        let index = self.read_pixel_index(
+                            sysbus,
+                            tile_addr,
+                            tile_x,
+                            tile_y as u32,
+                            4,
+                            pixel_format,
+                        );
+                        self.get_palette_color(sysbus, index as u32, entry.palette_bank as u32)
+                    }
+                    PixelFormat::BPP8 => {
+                        let index = self.read_pixel_index(
+                            sysbus,
+                            tile_addr,
+                            tile_x,
+                            tile_y as u32,
+                            8,
+                            pixel_format,
+                        );
+                        self.get_palette_color(sysbus, index as u32, 0)
+                    }
+                };
+                self.pixeldata[((px + tile_x) as usize) + py * 256] = color;
+            }
+            px += 8;
+            if px == bgcnt.screen_width as u32 {
+                return;
+            }
+        }
+    }
+
+    pub fn scanline(&mut self, sysbus: &mut SysBus) {
+        let dispcnt = DisplayControl::from(sysbus.ioregs.read_reg(REG_DISPCNT));
+        let dispstat = DisplayStatus::from(sysbus.ioregs.read_reg(REG_DISPSTAT));
+
+        match dispcnt.bg_mode {
+            BGMode::BGMode0 | BGMode::BGMode2 => {
+                for bg in 0..3 {
+                    if dispcnt.disp_bg[bg] {
+                        self.scanline_mode0(bg as u32, sysbus);
+                    }
+                }
+            }
+            _ => panic!("{:?} not supported", dispcnt.bg_mode),
+        }
     }
 }
 
 // *TODO* Running the Lcd step by step causes a massive performance impact, so for now not treat it as an emulated IO device.
-//
-// impl EmuIoDev for Lcd {
-//     fn step(&mut self, cycles: usize, sysbus: &mut SysBus) -> (usize, Option<Interrupt>) {
-//         self.cycles += cycles;
 
-//         sysbus
+impl EmuIoDev for Lcd {
-//             .ioregs
+    fn step(&mut self, cycles: usize, sysbus: &mut SysBus) -> (usize, Option<Interrupt>) {
-//             .write_reg(REG_VCOUNT, self.current_scanline as u16);
+        self.cycles += cycles;
+
+        sysbus
+            .ioregs
+            .write_reg(REG_VCOUNT, self.current_scanline as u16);
+        let mut dispstat = DisplayStatus::from(sysbus.ioregs.read_reg(REG_DISPSTAT));
+
+        dispstat.vcount_flag = dispstat.vcount_setting as usize == self.current_scanline;
+        if dispstat.vcount_irq_enable {
+            panic!("VCOUNT IRQ NOT IMPL");
+        }
+
+        match self.state {
+            HDraw => {
+                if self.cycles > Lcd::CYCLES_HDRAW {
+                    self.current_scanline += 1;
+                    self.cycles -= Lcd::CYCLES_HDRAW;
+
+                    let (new_state, irq) = if self.current_scanline < Lcd::DISPLAY_HEIGHT {
+                        self.scanline(sysbus);
+                        // HBlank
+                        dispstat.hblank_flag = true;
+                        let irq = if dispstat.hblank_irq_enable {
+                            Some(Interrupt::LCD_HBlank)
+                        } else {
+                            None
+                        };
+                        (HBlank, irq)
+                    } else {
+                        dispstat.vblank_flag = true;
+                        let irq = if dispstat.vblank_irq_enable {
+                            Some(Interrupt::LCD_VBlank)
+                        } else {
+                            None
+                        };
+                        (VBlank, irq)
+                    };
+                    self.state = new_state;
+                    self.update_regs(dispstat, sysbus);
+                    return (0, irq);
+                }
+            }
+            HBlank => {
+                if self.cycles > Lcd::CYCLES_HBLANK {
+                    self.cycles -= Lcd::CYCLES_HBLANK;
+                    self.state = HDraw;
+                    dispstat.hblank_flag = false;
+                    self.update_regs(dispstat, sysbus);
+                    return (0, None);
+                }
+            }
+            VBlank => {
+                if self.cycles > Lcd::CYCLES_VBLANK {
+                    self.cycles -= Lcd::CYCLES_VBLANK;
+                    self.state = HDraw;
+                    dispstat.vblank_flag = false;
+                    self.current_scanline = 0;
+                    self.scanline(sysbus);
+                    self.update_regs(dispstat, sysbus);
+                    return (0, None);
+                }
+            }
+        }
+
+        // let mut dispcnt = DisplayControl::from(sysbus.ioregs.read_reg(REG_DISPCNT));
         // let mut dispstat = DisplayStatus::from(sysbus.ioregs.read_reg(REG_DISPSTAT));
 
-//         dispstat.vcount_flag = dispstat.vcount_setting as usize == self.current_scanline;
+        // TODO
-//         if dispstat.vcount_irq_enable {
+        (0, None)
-//             panic!("VCOUNT IRQ NOT IMPL");
+    }
-//         }
+}
 
-//         match self.state {
+#[derive(Debug)]
-//             HDraw => {
+struct TileMapEntry {
-//                 if self.cycles > Lcd::CYCLES_HDRAW {
+    tile_index: u32,
-//                     self.current_scanline += 1;
+    x_flip: bool,
-//                     self.cycles -= Lcd::CYCLES_HDRAW;
+    y_flip: bool,
+    palette_bank: usize,
+}
 
-//                     let (new_state, irq) = if self.current_scanline < Lcd::DISPLAY_HEIGHT {
+impl From<u16> for TileMapEntry {
-//                         // HBlank
+    fn from(t: u16) -> TileMapEntry {
-//                         dispstat.hblank_flag = true;
+        TileMapEntry {
-//                         let irq = if dispstat.hblank_irq_enable {
+            tile_index: t.bit_range(0..10) as u32,
-//                             Some(Interrupt::LCD_HBlank)
+            x_flip: t.bit(10),
-//                         } else {
+            y_flip: t.bit(11),
-//                             None
+            palette_bank: t.bit_range(12..16) as usize,
-//                         };
+        }
-//                         (HBlank, irq)
+    }
-//                     } else {
+}
-//                         dispstat.vblank_flag = true;
-//                         let irq = if dispstat.vblank_irq_enable {
-//                             Some(Interrupt::LCD_HBlank)
-//                         } else {
-//                             None
-//                         };
-//                         (VBlank, irq)
-//                     };
-//                     self.state = new_state;
-//                     self.update_regs(dispstat, sysbus);
-//                     return (0, irq);
-//                 }
-//             }
-//             HBlank => {
-//                 if self.cycles > Lcd::CYCLES_HBLANK {
-//                     self.cycles -= Lcd::CYCLES_HBLANK;
-//                     self.state = HDraw;
-//                     dispstat.hblank_flag = false;
-//                     self.update_regs(dispstat, sysbus);
-//                     return (0, None);
-//                 }
-//             }
-//             VBlank => {
-//                 if self.cycles > Lcd::CYCLES_VBLANK {
-//                     self.cycles -= Lcd::CYCLES_VBLANK;
-//                     self.state = HDraw;
-//                     dispstat.vblank_flag = false;
-//                     self.current_scanline = 0;
-//                     self.update_regs(dispstat, sysbus);
-//                     return (0, None);
-//                 }
-//             }
-//         }
-
-//         // let mut dispcnt = DisplayControl::from(sysbus.ioregs.read_reg(REG_DISPCNT));
-//         // let mut dispstat = DisplayStatus::from(sysbus.ioregs.read_reg(REG_DISPSTAT));
-
-//         // TODO
-//         (0, None)
-//     }
-// }

src/palette.rs

@@ -3,7 +3,7 @@ use std::fmt;
 use byteorder::{LittleEndian, ReadBytesExt};
 use std::io::Cursor;
 
-#[derive(Debug, Copy, Clone)]
+#[derive(Debug, Copy, Clone, Default)]
 pub struct Rgb15 {
     pub r: u8,
     pub g: u8,
@@ -34,6 +34,12 @@ impl Rgb15 {
     }
 }
 
+#[derive(Debug, Primitive, Copy, Clone)]
+pub enum PixelFormat {
+    BPP4 = 0,
+    BPP8 = 1,
+}
+
 pub struct Palette {
     pub bg_colors: [Rgb15; 256],
     pub fg_colors: [Rgb15; 256],