Added set_cursor_position

src/vga.rs

@@ -170,6 +170,17 @@ impl Vga {
         self.crtc_controller_registers.read(emulation_mode, index)
     }
 
+    /// Writes `value` to the crtc controller, as determined by `index`.
+    pub fn write_crtc_controller(
+        &mut self,
+        emulation_mode: EmulationMode,
+        index: CrtcControllerIndex,
+        value: u8,
+    ) {
+        self.crtc_controller_registers
+            .write(emulation_mode, index, value);
+    }
+
     /// Returns the current `EmulationMode` as determined by the miscellaneous output register.
     pub fn get_emulation_mode(&mut self) -> EmulationMode {
         EmulationMode::from(self.general_registers.read_msr() & 0x1)

src/writers/text_40x25.rs

@@ -2,6 +2,7 @@ use super::ScreenCharacter;
 use crate::{
     colors::{Color16Bit, TextModeColor, DEFAULT_PALETTE},
     fonts::TEXT_8X16_FONT,
+    registers::CrtcControllerIndex,
     vga::{Vga, VideoMode, VGA},
 };
 use spinning_top::SpinlockGuard;
@@ -76,6 +77,30 @@ impl Text40x25 {
         vga.load_font(&TEXT_8X16_FONT);
     }
 
+    /// Sets the current text cursor to the position specified by
+    /// `x` and `y`.
+    ///
+    /// Panics if `x >= 40` or `y >= 25`.
+    pub fn set_cursor_position(&self, x: usize, y: usize) {
+        assert!(x < WIDTH, "x >= {}", WIDTH);
+        assert!(y < HEIGHT, "y >= {}", HEIGHT);
+        let offset = WIDTH * y + x;
+        let (mut vga, _frame_buffer) = self.get_frame_buffer();
+        let emulation_mode = vga.get_emulation_mode();
+        let cursor_start = offset & 0xFF;
+        let cursor_end = (offset >> 8) & 0xFF;
+        vga.write_crtc_controller(
+            emulation_mode,
+            CrtcControllerIndex::TextCursorLocationLow,
+            cursor_start as u8,
+        );
+        vga.write_crtc_controller(
+            emulation_mode,
+            CrtcControllerIndex::TextCursorLocationHigh,
+            cursor_end as u8,
+        );
+    }
+
     /// Returns the start of the `FrameBuffer` as `*mut ScreenCharacter`
     /// as well as a lock to the vga driver. This ensures the vga
     /// driver stays locked while the frame buffer is in use.

src/writers/text_40x50.rs

@@ -2,6 +2,7 @@ use super::ScreenCharacter;
 use crate::{
     colors::{Color16Bit, TextModeColor, DEFAULT_PALETTE},
     fonts::TEXT_8X8_FONT,
+    registers::CrtcControllerIndex,
     vga::{Vga, VideoMode, VGA},
 };
 use spinning_top::SpinlockGuard;
@@ -76,6 +77,30 @@ impl Text40x50 {
         vga.load_font(&TEXT_8X8_FONT);
     }
 
+    /// Sets the current text cursor to the position specified by
+    /// `x` and `y`.
+    ///
+    /// Panics if `x >= 40` or `y >= 50`.
+    pub fn set_cursor_position(&self, x: usize, y: usize) {
+        assert!(x < WIDTH, "x >= {}", WIDTH);
+        assert!(y < HEIGHT, "y >= {}", HEIGHT);
+        let offset = WIDTH * y + x;
+        let (mut vga, _frame_buffer) = self.get_frame_buffer();
+        let emulation_mode = vga.get_emulation_mode();
+        let cursor_start = offset & 0xFF;
+        let cursor_end = (offset >> 8) & 0xFF;
+        vga.write_crtc_controller(
+            emulation_mode,
+            CrtcControllerIndex::TextCursorLocationLow,
+            cursor_start as u8,
+        );
+        vga.write_crtc_controller(
+            emulation_mode,
+            CrtcControllerIndex::TextCursorLocationHigh,
+            cursor_end as u8,
+        );
+    }
+
     /// Returns the start of the `FrameBuffer` as `*mut ScreenCharacter`
     /// as well as a lock to the vga driver. This ensures the vga
     /// driver stays locked while the frame buffer is in use.

src/writers/text_80x25.rs

@@ -2,6 +2,7 @@ use super::ScreenCharacter;
 use crate::{
     colors::{Color16Bit, TextModeColor, DEFAULT_PALETTE},
     fonts::TEXT_8X16_FONT,
+    registers::CrtcControllerIndex,
     vga::{Vga, VideoMode, VGA},
 };
 use spinning_top::SpinlockGuard;
@@ -76,6 +77,30 @@ impl Text80x25 {
         vga.load_font(&TEXT_8X16_FONT);
     }
 
+    /// Sets the current text cursor to the position specified by
+    /// `x` and `y`.
+    ///
+    /// Panics if `x >= 80` or `y >= 25`.
+    pub fn set_cursor_position(&self, x: usize, y: usize) {
+        assert!(x < WIDTH, "x >= {}", WIDTH);
+        assert!(y < HEIGHT, "y >= {}", HEIGHT);
+        let offset = WIDTH * y + x;
+        let (mut vga, _frame_buffer) = self.get_frame_buffer();
+        let emulation_mode = vga.get_emulation_mode();
+        let cursor_start = offset & 0xFF;
+        let cursor_end = (offset >> 8) & 0xFF;
+        vga.write_crtc_controller(
+            emulation_mode,
+            CrtcControllerIndex::TextCursorLocationLow,
+            cursor_start as u8,
+        );
+        vga.write_crtc_controller(
+            emulation_mode,
+            CrtcControllerIndex::TextCursorLocationHigh,
+            cursor_end as u8,
+        );
+    }
+
     /// Returns the start of the `FrameBuffer` as `*mut ScreenCharacter`
     /// as well as a lock to the vga driver. This ensures the vga
     /// driver stays locked while the frame buffer is in use.