Initial 320x200x256 mode was way easier

src/configurations.rs

@@ -315,3 +315,77 @@ pub const MODE_640X480X16_CONFIGURATION: VgaConfiguration = VgaConfiguration {
         (AttributeControllerIndex::ColorSelect, 0x00),
     ],
 };
+
+/// Register values for Vga mode 640x480x16 Graphics.
+pub const MODE_320X200X256_CONFIGURATION: VgaConfiguration = VgaConfiguration {
+    // Configuration values acquired from https://www.singlix.com/trdos/archive/vga/Graphics%20in%20pmode.pdf
+    miscellaneous_output: 0x63,
+    sequencer_registers: &[
+        (SequencerIndex::SequencerReset, 0x03),
+        (SequencerIndex::ClockingMode, 0x01),
+        (SequencerIndex::PlaneMask, 0x0F),
+        (SequencerIndex::CharacterFont, 0x00),
+        (SequencerIndex::MemoryMode, 0x0E),
+    ],
+    crtc_controller_registers: &[
+        (CrtcControllerIndex::HorizontalTotal, 0x5F),
+        (CrtcControllerIndex::HorizontalDisplayEnableEnd, 0x4F),
+        (CrtcControllerIndex::HorizontalBlankingStart, 0x50),
+        (CrtcControllerIndex::HorizontalBlankingEnd, 0x82),
+        (CrtcControllerIndex::HorizontalSyncStart, 0x54),
+        (CrtcControllerIndex::HorizontalSyncEnd, 0x80),
+        (CrtcControllerIndex::VeritcalTotal, 0xBF),
+        (CrtcControllerIndex::Overflow, 0x1F),
+        (CrtcControllerIndex::PresetRowScan, 0x00),
+        (CrtcControllerIndex::MaximumScanLine, 0x41),
+        (CrtcControllerIndex::TextCursorStart, 0x00),
+        (CrtcControllerIndex::TextCursorEnd, 0x00),
+        (CrtcControllerIndex::StartAddressHigh, 0x00),
+        (CrtcControllerIndex::StartAddressLow, 0x00),
+        (CrtcControllerIndex::TextCursorLocationHigh, 0x00),
+        (CrtcControllerIndex::TextCursorLocationLow, 0x00),
+        (CrtcControllerIndex::VerticalSyncStart, 0x9C),
+        (CrtcControllerIndex::VerticalSyncEnd, 0x0E),
+        (CrtcControllerIndex::VerticalDisplayEnableEnd, 0x8F),
+        (CrtcControllerIndex::Offset, 0x28),
+        (CrtcControllerIndex::UnderlineLocation, 0x40),
+        (CrtcControllerIndex::VerticalBlankingStart, 0x96),
+        (CrtcControllerIndex::VerticalBlankingEnd, 0xB9),
+        (CrtcControllerIndex::ModeControl, 0xA3),
+        (CrtcControllerIndex::LineCompare, 0xFF),
+    ],
+    graphics_controller_registers: &[
+        (GraphicsControllerIndex::SetReset, 0x00),
+        (GraphicsControllerIndex::EnableSetReset, 0x00),
+        (GraphicsControllerIndex::ColorCompare, 0x00),
+        (GraphicsControllerIndex::DataRotate, 0x00),
+        (GraphicsControllerIndex::ReadPlaneSelect, 0x00),
+        (GraphicsControllerIndex::GraphicsMode, 0x40),
+        (GraphicsControllerIndex::Miscellaneous, 0x05),
+        (GraphicsControllerIndex::ColorDontCare, 0x0F),
+        (GraphicsControllerIndex::BitMask, 0xFF),
+    ],
+    attribute_controller_registers: &[
+        (AttributeControllerIndex::PaletteRegister0, 0x00),
+        (AttributeControllerIndex::PaletteRegister1, 0x01),
+        (AttributeControllerIndex::PaletteRegister2, 0x02),
+        (AttributeControllerIndex::PaletteRegister3, 0x03),
+        (AttributeControllerIndex::PaletteRegister4, 0x04),
+        (AttributeControllerIndex::PaletteRegister5, 0x05),
+        (AttributeControllerIndex::PaletteRegister6, 0x06),
+        (AttributeControllerIndex::PaletteRegister7, 0x07),
+        (AttributeControllerIndex::PaletteRegister8, 0x08),
+        (AttributeControllerIndex::PaletteRegister9, 0x09),
+        (AttributeControllerIndex::PaletteRegisterA, 0x0A),
+        (AttributeControllerIndex::PaletteRegisterB, 0x0B),
+        (AttributeControllerIndex::PaletteRegisterC, 0x0C),
+        (AttributeControllerIndex::PaletteRegisterD, 0x0D),
+        (AttributeControllerIndex::PaletteRegisterE, 0x0E),
+        (AttributeControllerIndex::PaletteRegisterF, 0x0F),
+        (AttributeControllerIndex::ModeControl, 0x41),
+        (AttributeControllerIndex::OverscanColor, 0x00),
+        (AttributeControllerIndex::MemoryPlaneEnable, 0x0F),
+        (AttributeControllerIndex::HorizontalPixelPanning, 0x00),
+        (AttributeControllerIndex::ColorSelect, 0x00),
+    ],
+};

src/vga.rs

@@ -2,8 +2,8 @@
 
 use super::{
     configurations::{
-        VgaConfiguration, MODE_40X25_CONFIGURATION, MODE_40X50_CONFIGURATION,
+        VgaConfiguration, MODE_320X200X256_CONFIGURATION, MODE_40X25_CONFIGURATION,
-        MODE_640X480X16_CONFIGURATION, MODE_80X25_CONFIGURATION,
+        MODE_40X50_CONFIGURATION, MODE_640X480X16_CONFIGURATION, MODE_80X25_CONFIGURATION,
     },
     fonts::VgaFont,
     registers::{
@@ -57,6 +57,8 @@ pub enum VideoMode {
     Mode40x50,
     /// Represents text mode 80x25.
     Mode80x25,
+    /// Represents graphics mode 320x200x256.
+    Mode320x200x256,
     /// Represents graphics mode 640x480x16.
     Mode640x480x16,
 }
@@ -98,6 +100,7 @@ impl Vga {
             VideoMode::Mode40x25 => self.set_video_mode_40x25(),
             VideoMode::Mode40x50 => self.set_video_mode_40x50(),
             VideoMode::Mode80x25 => self.set_video_mode_80x25(),
+            VideoMode::Mode320x200x256 => self.set_video_mode_320x200x256(),
             VideoMode::Mode640x480x16 => self.set_video_mode_640x480x16(),
         }
     }
@@ -266,6 +269,12 @@ impl Vga {
         self.most_recent_video_mode = Some(VideoMode::Mode80x25);
     }
 
+    /// Sets the video card to Mode 320x200x256.
+    fn set_video_mode_320x200x256(&mut self) {
+        self.set_registers(&MODE_320X200X256_CONFIGURATION);
+        self.most_recent_video_mode = Some(VideoMode::Mode320x200x256);
+    }
+
     /// Sets the video card to Mode 640x480x16.
     fn set_video_mode_640x480x16(&mut self) {
         self.set_registers(&MODE_640X480X16_CONFIGURATION);

src/writers/graphics_320x200x256.rs

@@ -0,0 +1,95 @@
+use super::{GraphicsWriter, Screen};
+use crate::{
+    colors::DEFAULT_PALETTE,
+    drawing::{Bresenham, Point},
+    vga::{Vga, VideoMode, VGA},
+};
+use font8x8::UnicodeFonts;
+use spinning_top::SpinlockGuard;
+
+const WIDTH: usize = 320;
+const HEIGHT: usize = 200;
+const SIZE: usize = WIDTH * HEIGHT;
+
+/// A basic interface for interacting with vga graphics mode 320x200x256.
+#[derive(Default)]
+pub struct Graphics320x200x256 {}
+
+impl Screen for Graphics320x200x256 {
+    #[inline]
+    fn get_width(&self) -> usize {
+        WIDTH
+    }
+
+    #[inline]
+    fn get_height(&self) -> usize {
+        HEIGHT
+    }
+
+    #[inline]
+    fn get_size(&self) -> usize {
+        SIZE
+    }
+}
+
+impl GraphicsWriter<u8> for Graphics320x200x256 {
+    fn clear_screen(&self, color: u8) {
+        for x in 0..WIDTH {
+            for y in 0..HEIGHT {
+                self.set_pixel(x, y, color);
+            }
+        }
+    }
+    fn draw_line(&self, start: Point<isize>, end: Point<isize>, color: u8) {
+        for (x, y) in Bresenham::new(start, end) {
+            self.set_pixel(x as usize, y as usize, color);
+        }
+    }
+    fn set_pixel(&self, x: usize, y: usize, color: u8) {
+        let (_vga, frame_buffer) = self.get_frame_buffer();
+        let offset = (y * WIDTH) + x;
+        unsafe {
+            frame_buffer.add(offset).write_volatile(color);
+        }
+    }
+    fn draw_character(&self, x: usize, y: usize, character: char, color: u8) {
+        let character = match font8x8::BASIC_FONTS.get(character) {
+            Some(character) => character,
+            // Default to a filled block if the character isn't found
+            None => font8x8::unicode::BLOCK_UNICODE[8].byte_array(),
+        };
+
+        for (row, byte) in character.iter().enumerate() {
+            for bit in 0..8 {
+                match *byte & 1 << bit {
+                    0 => (),
+                    _ => self.set_pixel(x + bit, y + row, color),
+                }
+            }
+        }
+    }
+    fn set_mode(&self) {
+        let mut vga = VGA.lock();
+        vga.set_video_mode(VideoMode::Mode320x200x256);
+
+        // Some bios mess up the palette when switching modes,
+        // so explicitly set it.
+        vga.color_palette_registers.load_palette(&DEFAULT_PALETTE);
+    }
+}
+
+impl Graphics320x200x256 {
+    /// Creates a new `Graphics320x200x256`.
+    pub fn new() -> Graphics320x200x256 {
+        Graphics320x200x256 {}
+    }
+
+    /// Returns the start of the `FrameBuffer` as `*mut u8` as
+    /// well as a lock to the vga driver. This ensures the vga
+    /// driver stays locked while the frame buffer is in use.
+    fn get_frame_buffer(&self) -> (SpinlockGuard<Vga>, *mut u8) {
+        let mut vga = VGA.lock();
+        let frame_buffer = vga.get_frame_buffer();
+        (vga, u32::from(frame_buffer) as *mut u8)
+    }
+}

src/writers/mod.rs

@@ -1,4 +1,5 @@
 //! Writers for common vga modes.
+mod graphics_320x200x256;
 mod graphics_640x480x16;
 mod text_40x25;
 mod text_40x50;
@@ -12,6 +13,7 @@ use super::{
 };
 use spinning_top::SpinlockGuard;
 
+pub use graphics_320x200x256::Graphics320x200x256;
 pub use graphics_640x480x16::Graphics640x480x16;
 pub use text_40x25::Text40x25;
 pub use text_40x50::Text40x50;