OS_Project/Part2/A4/01_gdb/kernel/kernel.c

/* This will force us to create a kernel entry function instead of jumping to kernel.c:0x00 */
void dummy_test_entrypoint() {
}
// use _start instead of main, kinda like begin for arduino
void _start() {
	char* video_memory = (char*) 0xb8000;
	*video_memory = 'X';
    unsigned char a;
    unsigned char b;
    a = 0;
    b = 0;
    for( int i = 1; i < 24; ++i) {
            for( int j = 0; j < 80; ++j) {
            *(video_memory + i*160 + j*2) = '.';
            }
    }

    *video_memory = 'Z';
    for( int i = 10; i < 20; ++i) {
            for( int j = 50; j < 60; ++j) {
            *(video_memory + i*160 + j*2) = 'X';
            }
    }
    while( 1) {
            *(video_memory+0) = b;
            *(video_memory+1) = ++a;
            b = b + a/255;
    }
}