.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 MAGIC, 0x1BADB002 /* 'magic number' lets bootloader find the header */ .set CHECKSUM, -(MAGIC + FLAGS) /* checksum of above, to prove we are multiboot */ .section .multiboot, "a" .align 4 .long MAGIC .long FLAGS .long CHECKSUM .section .text .global _start _start: cli mov $(page_directory - 0xC0000000), %ecx mov %cr4, %edx or $0x00000010, %edx mov %edx, %cr4 mov %ecx, %cr3 mov %cr0, %edx or $0x80000000, %edx mov %edx, %cr0 lea higher, %ecx jmp *%ecx higher: mov $stack_top, %esp mov $0xC0000000, %eax add %eax, %ebx push %ebx push %eax call kmain loop: hlt jmp loop .section .bss .align 16 stack_bottom: .skip 16384 # 16 KiB stack_top: .section .data, "a" .align 4096 .global page_directory page_directory: .long 0x00000083 .skip 3068 .long 0x00000083 .skip 1016 .long (page_directory - 0xC0000000) + 0x03