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global page_directory
global paging_init
global paging_finish
global KERNEL_MAPPING
KERNEL_MAPPING equ 0xC0000000
VGABUF equ 0x000B8000
section .bss
align 4096
page_directory:
resb 4096
page_table1:
resb 4096
section .bootstrap.text
align 8
paging_init:
extern kernel_start
extern kernel_end
paging_load:
mov edi, page_table1 - KERNEL_MAPPING
mov esi, 0
mov ecx, 1023
paging_cmp:
cmp esi, kernel_start
jl paging_add
cmp esi, kernel_end - KERNEL_MAPPING
jge paging_map
mov edx, esi
or edx, 0x003
mov [edi], edx
paging_add:
add esi, 4096
add edi, 4
loop paging_cmp
paging_map:
mov dword [page_table1 - KERNEL_MAPPING + 1023 * 4], VGABUF | 0x003
mov dword [page_directory - KERNEL_MAPPING + 0], page_table1 - KERNEL_MAPPING + 0x003
mov dword [page_directory - KERNEL_MAPPING + 768 * 4], page_table1 - KERNEL_MAPPING + 0x003
mov ecx, page_directory - KERNEL_MAPPING
mov cr3, ecx
mov ecx, cr0
or ecx, 0x80010000
mov cr0, ecx
ret
section .text
align 8
paging_finish:
mov dword [page_directory], 0
mov ecx, cr3
mov cr3, ecx
ret
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