Code: Select all
#include <stdint.h>
#include <stddef.h>
#include <limine.h>
// The Limine requests can be placed anywhere, but it is important that
// the compiler does not optimise them away, so, usually, they should
// be made volatile or equivalent.
static volatile struct limine_framebuffer_request framebuffer_request = {
.id = LIMINE_FRAMEBUFFER_REQUEST,
.revision = 0
};
// GCC and Clang reserve the right to generate calls to the following
// 4 functions even if they are not directly called.
// Implement them as the C specification mandates.
// DO NOT remove or rename these functions, or stuff will eventually break!
// They CAN be moved to a different .c file.
void *memcpy(void *dest, const void *src, size_t n) {
uint8_t *pdest = (uint8_t *)dest;
const uint8_t *psrc = (const uint8_t *)src;
for (size_t i = 0; i < n; i++) {
pdest[i] = psrc[i];
}
return dest;
}
void *memset(void *s, int c, size_t n) {
uint8_t *p = (uint8_t *)s;
for (size_t i = 0; i < n; i++) {
p[i] = (uint8_t)c;
}
return s;
}
void *memmove(void *dest, const void *src, size_t n) {
uint8_t *pdest = (uint8_t *)dest;
const uint8_t *psrc = (const uint8_t *)src;
if (src > dest) {
for (size_t i = 0; i < n; i++) {
pdest[i] = psrc[i];
}
} else if (src < dest) {
for (size_t i = n; i > 0; i--) {
pdest[i-1] = psrc[i-1];
}
}
return dest;
}
int memcmp(const void *s1, const void *s2, size_t n) {
const uint8_t *p1 = (const uint8_t *)s1;
const uint8_t *p2 = (const uint8_t *)s2;
for (size_t i = 0; i < n; i++) {
if (p1[i] != p2[i]) {
return p1[i] < p2[i] ? -1 : 1;
}
}
return 0;
}
// Halt and catch fire function.
static void hcf(void) {
asm ("cli");
for (;;) {
asm ("hlt");
}
}
// The following will be our kernel's entry point.
// If renaming _start() to something else, make sure to change the
// linker script accordingly.
void main_window(void) {
// Define the parameters for the square.
struct limine_framebuffer *framebuffer = framebuffer_request.response->framebuffers[0];
int x = 0;
int y = 0;
int size = 2000;
// Draw the square.
for (int i = 0; i < size; i++) {
uint32_t *fb_ptr = framebuffer->address;
int row = y + i;
int col_start = x;
int col_end = x + size - 1;
int col_count = col_end - col_start + 1;
int fb_pitch = framebuffer->pitch / 4;
uint32_t color = 0x7F7F7F; // White color.
for (int j = 0; j < col_count; j++) {
*(fb_ptr + row * fb_pitch + col_start + j) = color;
}
}
}
void draw_window(void) {
// Define the parameters for the square.
struct limine_framebuffer *framebuffer = framebuffer_request.response->framebuffers[0];
int x = 100;
int y = 100;
int size = 100;
// Draw the square.
for (int i = 0; i < size; i++) {
uint32_t *fb_ptr = framebuffer->address;
int row = y + i;
int col_start = x;
int col_end = x + size - 1;
int col_count = col_end - col_start + 1;
int fb_pitch = framebuffer->pitch / 4;
uint32_t color = 0xFFFFFF; // White color.
for (int j = 0; j < col_count; j++) {
*(fb_ptr + row * fb_pitch + col_start + j) = color;
}
}
}
void _start(void) {
// Ensure we got a framebuffer.
if (framebuffer_request.response == NULL
|| framebuffer_request.response->framebuffer_count < 1) {
hcf();
}
// Fetch the first framebuffer.
struct limine_framebuffer *framebuffer = framebuffer_request.response->framebuffers[0];
// Note: we assume the framebuffer model is RGB with 32-bit pixels.
main_window();
draw_window();
// We're done, just hang...
hcf();
}
