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.code16gcc
#include "assembly.h"
.section .init
ENTRY(pm_entry)
xor %ax, %ax
mov %ax, %ds
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
mov %ax, %ss
mov $0x7c00, %sp
mov %cr0, %eax
and $~((1 << 30) | (1 << 29)), %eax # clear CD and NW
or $1, %al
mov %eax, %cr0
lgdtl %cs:0xff80 + gdt32_descr - pm_entry
ljmpl $8, $0xffffff80 + 2f - pm_entry
2:
.code32
mov $16, %ax
mov %ax, %ds
mov %ax, %es
mov %ax, %fs
mov %ax, %gs
mov %ax, %ss
ljmp $8, $0xffff0000
gdt32:
.quad 0
.quad 0x00cf9b000000ffff // flat 32-bit code segment
.quad 0x00cf93000000ffff // flat 32-bit data segment
.quad 0x000f9b0f0000ffff // 64K 16-bit code segment at 0xF0000
.quad 0x000f93000000ffff // 64K 16-bit data segment at 0x0
gdt32_end:
gdt32_descr:
.word gdt32_end - gdt32 - 1
.long 0xffffff80 + gdt32 - pm_entry
ENTRY_END(pm_entry)
.code16gcc
.section .resetvector
jmp pm_entry
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