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%include "gdt.inc"
[ORG 0x1388000]
[BITS 32]
[SECTION .text]
mboot:
db 'M'
db 'Z'
KERNEL_LOADADDR???       equ 0x1900000
MULTIBOOT_PAGE_ALIGN   equ 1<<0
MULTIBOOT_MEMORY_INFO  equ 1<<1
MULTIBOOT_AOUT_KLUDGE  equ 1<<16
MULTIBOOT_HEADER_MAGIC equ 0x1BADB002
MULTIBOOT_HEADER_FLAGS equ MULTIBOOT_PAGE_ALIGN | MULTIBOOT_MEMORY_INFO | MULTIBOOT_AOUT_KLUDGE
CHECKSUM               equ -(MULTIBOOT_HEADER_MAGIC + MULTIBOOT_HEADER_FLAGS)
align 4
dd MULTIBOOT_HEADER_MAGIC
dd MULTIBOOT_HEADER_FLAGS
dd CHECKSUM
; fields used if MULTIBOOT_AOUT_KLUDGE is set in MULTIBOOT_HEADER_FLAGS
dd 0x1388004
dd 0x1388000 
dd 0x0
dd 0x0
dd code
dd 0x0
dd 0x50
dd 0x19
dd 0x0
mboot_end:
resb 0x3C - (mboot_end - mboot)
pe32ptr:
dd 0x0
VarImageBase dd 0x0
VarSectionCount dd 0x0
VarEntryPoint dd 0x0
VarBaseOfCode dd 0x0
VarMultiBootInfo dd 0x0
pgdt:
start_gdt
???desc 0x0, 0xFFFFF, D_CODE+D_WRITE+D_BIG+D_BIG_LIM
???desc 0x0, 0xFFFFF, D_DATA+D_WRITE+D_BIG+D_BIG_LIM
???desc 0x0, 0xFFFFF, D_DATA+D_WRITE+D_BIG+D_BIG_LIM
end_gdt
code:
mov DWORD [VarMultiBootInfo], ebx
mov edi, DWORD [pe32ptr]
add edi, 0x1388000
findpesig:
mov ebx, dword [edi]?????????; TEST
cmp dword [edi], 0x4550
???jz foundpesig
inc edi
jmp findpesig
foundpesig:
add edi, 4????????????; jump past PE signature.
and ebx, 0????????????; clear ebx
mov ebx, 0
mov bx, word [edi + 2]?????????; get count of sections
mov DWORD [VarSectionCount], ebx??????
mov bx, word [edi + 16]?????????; get optional header size
add edi, 20????????????; jump past PE header
mov eax, edi
mov edi, DWORD [edi+28]?????????; get image base (preferred load address) NT-Specific
mov DWORD [VarImageBase], edi
mov edi, eax????????????; restore edi
mov edi, DWORD [edi+16]?????????; get address of entry point
mov DWORD [VarEntryPoint], edi
mov edi, eax????????????; restore edi
mov edi, DWORD [edi+20]?????????; get BaseOfCode
mov DWORD [VarBaseOfCode], edi
mov edi, eax????????????; restore edi
add edi, ebx????????????; jump past PE optional header
; edi = offset zero of section table


mov eax, 0
mov eax, DWORD [VarSectionCount]??????
mov edx, 40
mul edx???????????????; compute total size of section table
add eax, edi????????????; compute last byte + 1 of section table
mov DWORD [VarSectionCount], eax???; store computation
mov esp, edi

sectionnext:
mov eax, esp????????????; restore eax
mov edi, eax????????????; set edi to read section
cmp eax, DWORD [VarSectionCount]
??? jz sectiondone?????????; No more sections to load.
add eax, 40????????????; jump to next section in table
mov esp, eax????????????; save eax our count

loadsection:????????????; relocations not implemented
add edi, 12
mov ecx, DWORD [edi]?????????; get section.virtualAddress
add ecx, [VarImageBase]?????????; compute physical address
add edi, 4????????????; jump to size of raw data
mov ebx, DWORD [edi]?????????; get size of raw data
cmp ebx, 0
???jz copydone?????????; section contains no data
add edi, 4????????????; jump to ptr to raw data
mov edx, DWORD [edi]?????????; get ptr to raw data
mov edi, 0x1388000?????????; grub --> image (load address)
add edi, edx????????????; jump to first byte of section .text
copyimage:
mov al, BYTE [edi]
inc edi
xchg edi, ecx
mov BYTE [edi], al
inc edi
xchg ecx, edi
mov eax, edi
sub eax, edx
sub eax, 0x1388000
cmp eax, ebx
???jz copydone
jmp copyimage
copydone:????????????; image copy is complete
jmp sectionnext
sectiondone:
lgdt [pgdt]
mov eax, DWORD [VarEntryPoint]
mov ebx, DWORD [VarImageBase]
add eax, ebx
mov ebx, DWORD [VarMultiBootInfo]???; Multiboot Compliance
jmp eax

pe32: