Plane refactor

Cargo.toml

@@ -19,6 +19,7 @@ repository = "https://github.com/rust-osdev/vga"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+bitflags = "1.2.1"
 conquer-once = { version = "0.2.0", default-features = false }
 spinning_top = { version = "0.1.0", features = ["nightly"] }
 x86_64 = "0.9.6"

src/registers.rs

@@ -58,7 +58,7 @@ pub enum SequencerIndex {
     SequencerReset = 0x0,
     /// Represents the `Clocking Mode` register index.
     ClockingMode = 0x1,
-    /// Represents the Plane/Map mask register index.
+    /// Represents the `Plane/Map` mask register index.
     PlaneMask = 0x2,
     /// Represents the `Character Font` register index.
     CharacterFont = 0x3,

src/vga.rs

@@ -13,7 +13,9 @@ use super::{
         GraphicsControllerIndex, GraphicsControllerRegisters, SequencerIndex, SequencerRegisters,
     },
 };
+use bitflags::bitflags;
 use conquer_once::spin::Lazy;
+use core::convert::TryFrom;
 use spinning_top::Spinlock;
 
 /// Provides mutable access to the vga graphics card.
@@ -49,11 +51,11 @@ impl From<FrameBuffer> for u32 {
     }
 }
 
-/// Represents a plane for reading and writing vga data.
+/// Represents a plane for the `GraphicsControllerIndex::ReadPlaneSelect` register.
 #[allow(dead_code)]
 #[derive(Debug, Copy, Clone)]
 #[repr(u8)]
-pub enum Plane {
+pub enum ReadPlane {
     /// Represents `Plane 0 (0x0)`.
     Plane0 = 0x0,
     /// Represents `Plane 1 (0x1)`.
@@ -64,12 +66,60 @@ pub enum Plane {
     Plane3 = 0x3,
 }
 
-impl From<Plane> for u8 {
+impl TryFrom<u8> for ReadPlane {
-    fn from(value: Plane) -> u8 {
+    type Error = &'static str;
+
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
+        match value {
+            0 => Ok(ReadPlane::Plane0),
+            1 => Ok(ReadPlane::Plane1),
+            2 => Ok(ReadPlane::Plane2),
+            3 => Ok(ReadPlane::Plane3),
+            _ => Err("ReadPlane only accepts values between 0-3!"),
+        }
+    }
+}
+
+impl From<ReadPlane> for u8 {
+    fn from(value: ReadPlane) -> u8 {
         value as u8
     }
 }
 
+bitflags! {
+    /// Represents the plane masks of the `SequencerIndex::PlaneMask` register.
+    pub struct PlaneMask: u8 {
+        /// Represents `Plane0` of vga memory.
+        const PLANE0 = 0b00000001;
+        /// Represents `Plane1` of vga memory.
+        const PLANE1 = 0b00000010;
+        /// Represents `Plane2` of vga memory.
+        const PLANE2 = 0b00000100;
+        /// Represents `Plane3` of vga memory.
+        const PLANE3 = 0b00001000;
+    }
+}
+
+impl TryFrom<u8> for PlaneMask {
+    type Error = &'static str;
+
+    fn try_from(value: u8) -> Result<Self, Self::Error> {
+        match value {
+            0 => Ok(PlaneMask::PLANE0),
+            1 => Ok(PlaneMask::PLANE1),
+            2 => Ok(PlaneMask::PLANE2),
+            3 => Ok(PlaneMask::PLANE3),
+            _ => Err("PlaneMask only accepts values between 0-3!"),
+        }
+    }
+}
+
+impl From<PlaneMask> for u8 {
+    fn from(value: PlaneMask) -> u8 {
+        value.bits()
+    }
+}
+
 /// Represents a specified vga video mode.
 #[derive(Debug, Clone, Copy)]
 pub enum VideoMode {
@@ -226,7 +276,7 @@ impl Vga {
         );
 
         // Write font to plane
-        self.set_plane(Plane::Plane2);
+        self.set_plane_mask(PlaneMask::PLANE2);
 
         let frame_buffer = u32::from(self.get_frame_buffer()) as *mut u8;
 
@@ -286,16 +336,17 @@ impl Vga {
         )
     }
 
-    /// Turns on the given `Plane` in the vga graphics card.
+    /// Sets the plane mask of the sequencer controller, as specified by `plane_mask`.
-    pub fn set_plane(&mut self, plane: Plane) {
+    pub fn set_plane_mask(&mut self, plane_mask: PlaneMask) {
-        let mut plane = u8::from(plane);
-
-        plane &= 0x3;
-
-        self.graphics_controller_registers
-            .write(GraphicsControllerIndex::ReadPlaneSelect, plane);
         self.sequencer_registers
-            .write(SequencerIndex::PlaneMask, 0x1 << plane);
+            .write(SequencerIndex::PlaneMask, u8::from(plane_mask));
+    }
+
+    /// Sets the read plane of the graphics controller, as specified by `read_plane`.
+    pub fn set_read_plane(&mut self, read_plane: ReadPlane) {
+        let read_plane = u8::from(read_plane) & 0x3;
+        self.graphics_controller_registers
+            .write(GraphicsControllerIndex::ReadPlaneSelect, read_plane);
     }
 
     fn set_registers(&mut self, configuration: &VgaConfiguration) {

src/writers/graphics_640x480x16.rs

@@ -1,14 +1,13 @@
 use crate::{
     colors::{Color16Bit, DEFAULT_PALETTE},
-    vga::{Plane, Vga, VideoMode, VGA},
+    vga::{Vga, VideoMode, VGA},
 };
+use core::convert::TryInto;
 use spinning_top::SpinlockGuard;
 
 const WIDTH: usize = 640;
 const HEIGHT: usize = 480;
 
-static PLANES: &[Plane] = &[Plane::Plane0, Plane::Plane1, Plane::Plane2, Plane::Plane3];
-
 /// A basic interface for interacting with vga graphics mode 640x480x16
 ///
 /// # Examples
@@ -37,7 +36,7 @@ impl Graphics640x480x16 {
         // TODO: Clear the screen by using 4-plane mode instead of slow `set_pixel`.
         for x in 0..WIDTH {
             for y in 0..HEIGHT {
-                self.set_pixel(x, y, Color16Bit::Yellow);
+                self.set_pixel(x, y, Color16Bit::Black);
             }
         }
     }
@@ -56,8 +55,9 @@ impl Graphics640x480x16 {
         let mask = 0x80 >> (x & 7);
         let mut plane_mask = 0x01;
 
-        for plane in PLANES {
+        for plane in 0u8..4u8 {
-            vga.set_plane(*plane);
+            vga.set_read_plane(plane.try_into().unwrap());
+            vga.set_plane_mask(plane.try_into().unwrap());
             let current_value = unsafe { frame_buffer.add(offset).read_volatile() };
             let new_value = if plane_mask & color as u8 != 0 {
                 current_value | mask