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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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24
kernel/boot/boot.S
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@@ -1,14 +1,26 @@
.set ALIGN, 1<<0 /* align loaded modules on page boundaries */
.set MEMINFO, 1<<1 /* provide memory map */
.set FLAGS, ALIGN | MEMINFO /* this is the Multiboot 'flag' field */
.set GRAPHICS, 1<<2 /* <-- NEW: Request video mode table/framebuffer from GRUB */
.set FLAGS, ALIGN | MEMINFO | GRAPHICS /* Updated to include GRAPHICS */
.set MAGIC, 0x1BADB002 /* 'magic number' lets bootloader find the header */
.set CHECKSUM, -(MAGIC + FLAGS) /* checksum of above, to prove we are multiboot */
.set CHECKSUM, -(MAGIC + FLAGS) /* recalculated checksum of the new flags */
.section .multiboot, "a"
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM
.long 0 /* header_addr */
.long 0 /* load_addr */
.long 0 /* load_end_addr */
.long 0 /* bss_end_addr */
.long 0 /* entry_addr */
.long 0 /* Mode Type: 0 = Linear Framebuffer, 1 = Standard EGA Text */
.long 1024 /* Width (Pixels) */
.long 768 /* Height (Pixels) */
.long 32 /* Color Depth (Bits Per Pixel) */
.section .text
.global _start

83
kernel/drivers/vga/vga.c
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@@ -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);

17
kernel/kmain.c
View File

@@ -97,12 +97,23 @@ void load_root_program(const char* path) {
void kmain(uint32_t magic, multiboot_info* mbi) {
disable_interrupts();
if (!(mbi->flags & (1 << 6))) {
vga_init(mbi->framebuffer_addr,
mbi->framebuffer_width,
mbi->framebuffer_height,
mbi->framebuffer_pitch,
mbi->framebuffer_bpp);
if (magic != 0x2BADB002) {
return;
}
// need mmap and fb info
if (!(mbi->flags & (1 << 6)) || !(mbi->flags & (1 << 12))) {
return;
}
vga_init();
return;
uint32_t mmap_virtual_addr = mbi->mmap_addr + 0xC0000000;
init_pmm((void*)mmap_virtual_addr, mbi->mmap_length);
kprintf("memory detection complete. total free memory: %dMB\n", total_free_memory() / 1024 / 1024);

23
kernel/multiboot.h
View File

@@ -17,6 +17,29 @@ typedef struct {
uint32_t shndx;
uint32_t mmap_length;
uint32_t mmap_addr;
uint32_t drives_length;
uint32_t drives_addr;
uint32_t config_table;
uint32_t boot_loader_name;
uint32_t apm_table;
uint32_t vbe_control_info;
uint32_t vbe_mode_info;
uint16_t vbe_mode;
uint16_t vbe_interface_seg;
uint16_t vbe_interface_off;
uint16_t vbe_interface_len;
uint64_t framebuffer_addr;
uint32_t framebuffer_pitch;
uint32_t framebuffer_width;
uint32_t framebuffer_height;
uint8_t framebuffer_bpp;
uint8_t framebuffer_type;
uint8_t red_field_position;
uint8_t red_mask_size;
uint8_t green_field_position;
uint8_t green_mask_size;
uint8_t blue_field_position;
uint8_t blue_mask_size;
} __attribute__((packed)) multiboot_info;
typedef struct {

20
kernel/syscall.c
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@@ -95,6 +95,25 @@ static int32_t sys_brk(uint32_t new_break) {
return current->heap_end;
}
static int32_t sys_sbrk(int32_t inc) {
process_t* current = current_task();
if (inc <= 0) { // can't shrink yet
return current->heap_end;
}
uint32_t page_start = (current->heap_end + 4095) & ~4095;
current->heap_end += inc;
uint32_t page_end = (current->heap_end + 4095) & ~4095;
for (uint32_t addr = page_start; addr < page_end; addr += 4096) {
void* phys = p_alloc_frame();
map_page(addr, (uint32_t)phys, PAGE_PRESENT | PAGE_WRITABLE | PAGE_USER);
}
return current->heap_end;
}
static int32_t sys_pty(int* slave_fd) {
pty_t* pty = (pty_t*)kalloc(sizeof(pty_t));
ring_buf_init(&pty->master_rb);
@@ -230,6 +249,7 @@ void syscall(registers_t* regs) {
case 5: ret = sys_open((const char*)regs->ebx, regs->ecx); break;
case 6: ret = sys_close(regs->ebx); break;
case 12: ret = sys_brk(regs->ebx); break;
case 13: ret = sys_sbrk(regs->ebx); break;
case 20: ret = sys_pty((int*)regs->ebx); break;
case 21: ret = sys_fork(regs); break;
case 22: ret = sys_exec(regs, (const char*)regs->ebx); break;