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trying to get VGA fb mode to work..

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slinky55
2026-07-14 00:07:50 -05:00
parent 5c7febbbf0
commit 454de8feed
17 changed files with 567 additions and 300 deletions
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83
kernel/drivers/vga/vga.c
View File

@@ -7,9 +7,12 @@
#include <common.h>
#define VGA_WIDTH 80
#define VGA_HEIGHT 25
#define VGA_MEMORY (0xB8000 + 0xC0000000)
static uint32_t framebuffer_address;
static uint32_t framebuffer_width;
static uint32_t framebuffer_height;
static uint32_t framebuffer_total_pixels;
static uint32_t framebuffer_pitch;
static uint32_t framebuffer_bpp;
enum vga_color {
VGA_COLOR_BLACK = 0,
@@ -30,52 +33,39 @@ enum vga_color {
VGA_COLOR_WHITE = 15,
};
static size_t terminal_row;
static size_t terminal_column;
static uint8_t terminal_color;
static uint16_t* terminal_buffer = (uint16_t*)VGA_MEMORY;
void vga_init(
uint32_t fb_vaddr,
uint32_t fb_width,
uint32_t fb_height,
uint32_t fb_pitch,
uint8_t fb_bpp
) {
framebuffer_address = fb_vaddr;
framebuffer_width = fb_width;
framebuffer_height = fb_height;
framebuffer_pitch = fb_pitch;
framebuffer_bpp = fb_bpp;
static inline uint8_t vga_entry_color(enum vga_color fg, enum vga_color bg)
{
return fg | bg << 4;
framebuffer_total_pixels = framebuffer_width * framebuffer_height;
vga_clear_scrn(0xFFFFFFFF);
}
static inline uint16_t vga_entry(unsigned char uc, uint8_t color)
{
return (uint16_t) uc | (uint16_t) color << 8;
}
void vga_clear_scrn(uint32_t color) {
if (framebuffer_address == 0) return;
static void update_cursor()
{
uint16_t pos = terminal_row * VGA_WIDTH + terminal_column;
outb(0x3D4, 0x0F);
outb(0x3D5, (uint8_t) (pos & 0xFF));
outb(0x3D4, 0x0E);
outb(0x3D5, (uint8_t) ((pos >> 8) & 0xFF));
}
void vga_init() {
outb(0x3D4, 0x0A);
outb(0x3D5, (inb(0x3D5) & 0xC0) | 14);
outb(0x3D4, 0x0B);
outb(0x3D5, (inb(0x3D5) & 0xE0) | 15);
terminal_row = 0;
terminal_column = 0;
terminal_color = vga_entry_color(VGA_COLOR_LIGHT_GREY, VGA_COLOR_BLACK);
for (size_t y = 0; y < VGA_HEIGHT; y++) {
for (size_t x = 0; x < VGA_WIDTH; x++) {
const size_t index = y * VGA_WIDTH + x;
terminal_buffer[index] = vga_entry(' ', terminal_color);
}
}
// Completely ignore the framebuffer address for a split second.
// Let's force raw ASCII text into the legacy VGA text console area.
uint16_t* text_mode_buffer = (uint16_t*)0xB8000;
// Fill the screen with 'A' characters on a red background
for (int i = 0; i < 80 * 25; i++) {
text_mode_buffer[i] = (0x4F << 8) | 'A';
}
}
void vga_putchar(char c) {
if (c == '\n') {
terminal_row++;
terminal_column = 0;
return;
}
@@ -85,19 +75,9 @@ void vga_putchar(char c) {
}
return;
}
const size_t index = terminal_row * VGA_WIDTH + terminal_column;
terminal_buffer[index] = vga_entry(c, terminal_color);
if (++terminal_column == VGA_WIDTH) {
terminal_column = 0;
if (++terminal_row == VGA_HEIGHT)
terminal_row = 0;
}
}
uint32_t vga_seek(vfs_node_t* node, uint32_t offset, int whence) {
terminal_row = offset / VGA_WIDTH;
terminal_column = offset % VGA_WIDTH;
return 0;
}
@@ -105,6 +85,5 @@ uint32_t vga_write(vfs_node_t* node, uint32_t offset, uint32_t size, uint8_t* bu
for (uint32_t i = 0; i < size; i++) {
vga_putchar((char)buf[i]);
}
update_cursor();
return size;
}

10
kernel/drivers/vga/vga.h
View File

@@ -3,7 +3,15 @@
#include <vfs.h>
void vga_init();
void vga_init(
uint32_t fb_vaddr,
uint32_t fb_width,
uint32_t fb_height,
uint32_t fb_pitch,
uint8_t fb_bpp
);
void vga_clear_scrn(uint32_t color);
void vga_putchar(char c);
uint32_t vga_write(vfs_node_t* node, uint32_t offset, uint32_t size, uint8_t* buf);