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80 lines
3.1 KiB
C
80 lines
3.1 KiB
C
#include "display.h"
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#include "io.h"
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#include "vga.h"
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// Initialize the display
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void init_display(void) {
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// Initialize the VGA driver. This typically sets up the 80x25 text mode,
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// clears the screen, and sets the cursor.
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vga_init();
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}
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// Enumerate connected displays
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void enumerate_displays(void) {
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// This function is often a complex operation in a real driver.
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// In this simplified kernel/VGA text mode environment, we use printf
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// to output a message and rely on the fact that VGA is present.
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// Clear the display before printing a message
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vga_clear(vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK));
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// Output a simplified enumeration message
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vga_printf("Display: Standard VGA Text Mode (80x25) Detected.\n");
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// In a real driver, you would use inb() and outb() with specific VGA ports
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// to read information (e.g., from the CRTC registers 0x3D4/0x3D5)
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// to check for display presence or configuration.
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}
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// Set the display mode
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// NOTE: Setting arbitrary VGA modes (like 0x13 for 320x200) is very complex
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// and requires writing hundreds of register values, often done via BIOS in
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// real mode. Since we are in protected mode and have a simple text driver,
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// this function is kept simple or treated as a placeholder for full mode changes.
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void set_display_mode(uint8_t mode) {
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// Check if the requested mode is a known mode (e.g., VGA Text Mode 3)
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// For this example, we simply acknowledge the call.
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// A true mode set would involve complex register sequencing.
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// The provided vga.c is a Text Mode driver, so a graphical mode set
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// like 0x13 (320x200 256-color) would break the existing vga_printf functionality.
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// A simplified text-mode-specific response:
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if (mode == 0x03) { // Mode 3 is standard 80x25 text mode
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vga_printf("Display mode set to 80x25 Text Mode (Mode 0x03).\n");
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vga_init(); // Re-initialize the text mode
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} else {
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// Simple I/O example based on the original structure (Caution: Incomplete for full mode set)
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outb(VGA_PORT, mode); // Example function to write to a port
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vga_printf("Attempting to set display mode to 0x%x. (Warning: May break current display)\n", mode);
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}
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}
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// Clear the display
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void clear_display(void) {
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// Use the VGA driver's clear function, typically clearing to black on light grey
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// or black on black. We'll use the black on light grey from vga_init for consistency.
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vga_clear(vga_entry_color(VGA_COLOR_BLACK, VGA_COLOR_LIGHT_GREY));
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// Reset cursor to 0, 0
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vga_set_cursor_position(0, 0);
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}
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// Helper function to write a string
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void display_write_string(const char* str) {
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// Use the VGA driver's string writing function
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vga_write_string(str, my_strlen(str));
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}
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// Helper function to print a formatted string
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void display_printf(const char* format, ...) {
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// Use the VGA driver's printf function
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va_list args;
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va_start(args, format);
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// The vga_printf function already handles the va_list internally,
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// so we can just call it directly.
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vga_printf(format, args);
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va_end(args);
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}
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