diff options
Diffstat (limited to 'setup.S')
| -rw-r--r-- | setup.S | 21 |
1 files changed, 9 insertions, 12 deletions
@@ -22,18 +22,11 @@ start: outb %al, $0x70 # The system will move itself to its rightful place. -# reload the segment registers and the stack since the -# APs also execute this code -#ljmp $INITSEG, $(reload - start + 0x200) -reload: - movw $INITSEG, %ax + xorl %eax, %eax + movw %cs, %ax movw %ax, %ds - movw %ax, %es - movw %ax, %fs - movw %ax, %ss # reset the stack to INITSEG:0x4000-12. - movw %dx, %sp - push %cs - pop %ds + shll $4, %eax + addl %eax, gdt_48 - start + 2 lidt idt_48 - start # load idt with 0,0 lgdt gdt_48 - start # load gdt with whatever appropriate @@ -80,6 +73,9 @@ alt_a20_done: * Note that the short jump isn't strictly needed, althought there are * reasons why it might be a good idea. It won't hurt in any case. */ + xorl %ebx, %ebx + movw %ss, %bx + shll $4, %ebx movw $0x0001, %ax # protected mode (PE) bit lmsw %ax # This is it# jmp flush_instr @@ -88,6 +84,7 @@ flush_instr: movw %ax, %ds movw %ax, %es movw %ax, %ss + addl %ebx, %esp movw %ax, %fs movw %ax, %gs @@ -144,7 +141,7 @@ idt_48: gdt_48: .word 0x800 # gdt limit=2048, 256 GDT entries - .word 512+gdt - start,0x9 # gdt base = 0X9xxxx + .long gdt - start # gdt base msg1: .asciz "Setup.S\r\n" |