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.bss
. = . + 4096
.align 16
stacktop:
. = . + 4096
.align 16
ring0stacktop:
.data
.align 4096
ptl2:
i = 0
.rept 512
.quad 0x1e7 | (i << 21)
i = i + 1
.endr
.align 4096
ptl3:
.quad ptl2 + 7
.align 4096
ptl4:
.quad ptl3 + 7
.align 4096
gdt64_desc:
.word gdt64_end - gdt64 - 1
.quad gdt64
gdt64:
.quad 0
.quad 0x00af9b000000ffff // 64-bit code segment
.quad 0x00cf93000000ffff // 64-bit data segment
.quad 0x00affb000000ffff // 64-bit code segment (user)
.quad 0x00cff3000000ffff // 64-bit data segment (user)
tss_descr:
.quad 0x000089000000ffff // 64-bit avail tss
.quad 0 // tss high addr
gdt64_end:
tss:
.long 0
.quad ring0stacktop
.quad 0, 0, 0
.quad 0, 0, 0, 0, 0, 0, 0, 0
.long 0, 0, 0
.section .init
.code32
lgdt gdt64_desc
mov %cr4, %eax
bts $5, %eax // pae
mov %eax, %cr4
mov $ptl4, %eax
mov %eax, %cr3
efer = 0xc0000080
mov $efer, %ecx
rdmsr
bts $8, %eax
wrmsr
mov %cr0, %eax
bts $0, %eax
bts $31, %eax
mov %eax, %cr0
jmpl $8, $start64
.code64
start64:
lea stacktop, %rsp
mov $0, %eax
mov %ax, %ss
mov $tss, %rax
mov %ax, tss_descr+2
shr $16, %rax
mov %al, tss_descr+4
shr $8, %rax
mov %al, tss_descr+7
shr $8, %rax
mov %eax, tss_descr+8
mov $(tss_descr-gdt64), %rax
ltr %ax
call main
1: // hlt
jmp 1b
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