| 54,8 → 54,9 |
|---|
| movl %cr0,%eax |
| orl $0x1,%eax |
| movl %eax,%cr0 # switch to protected mode |
| jmpl $8,$meeting_point |
| |
| jmpl $8, $boot_image_start |
| |
| .code32 |
| .align 4 |
| multiboot_header: |
| 62,18 → 63,40 |
|---|
| .long MULTIBOOT_HEADER_MAGIC |
| .long MULTIBOOT_HEADER_FLAGS |
| .long -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS) # checksum |
| .long multiboot_header |
| .long unmapped_ktext_start |
| .long multiboot_header + BOOT_OFFSET |
| .long unmapped_ktext_start + BOOT_OFFSET |
| .long 0 |
| .long 0 |
| .long multiboot_image_start |
| .long multiboot_image_start + BOOT_OFFSET |
| |
| boot_image_start: |
| movw $16, %ax |
| movw %ax, %es |
| movw %ax, %gs |
| movw %ax, %fs |
| movw %ax, %ds # kernel data + stack |
| movw %ax, %ss |
| |
| call map_kernel # map kernel and turn paging on |
| |
| movb $0xd1, %al # enable A20 using the keyboard controller |
| outb %al, $0x64 |
| movb $0xdf, %al |
| outb %al, $0x60 |
| |
| movl $0x8000, %esi |
| movl $0x8000 + BOOT_OFFSET, %edi |
| movl $_hardcoded_kernel_size, %ecx |
| cld |
| rep movsb |
| |
| jmp protected |
| |
| multiboot_image_start: |
| movl $0x7c00, %esp # initialize stack pointer |
| |
| lgdt gdtr |
| |
| meeting_point: |
| movw $16,%ax |
| movw %ax,%es |
| movw %ax,%gs |
| 83,6 → 106,7 |
|---|
| |
| call map_kernel # map kernel and turn paging on |
| |
| protected: |
| call main_bsp # never returns |
| |
| cli |