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xor RAX, RAX
add RAX, 48
mov byte [DS:0B8000], AL

xor RBX, RBX
add RBX, 48
mov byte [DS:0B8002], BL

xor RCX, RCX
add RCX, 48
mov byte [DS:0B8004], CL

xor RDX, RDX
add RDX, 48
mov byte [DS:0B8006], DL

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;.....

;Reading the e820 output, I run out of available registers and use BP, after that not restore it, I need to do it?

;.....

;My stack is set up next to entering protect mode:
protect_code:
mov AX, Data_Selector
mov DS, AX
mov SS, AX
mov ESP, 090h              ;I put here random number, it seems to works whatever put here, I don't understand the stack very fine  :oops: 

;.......

cli

;........

;Here I modify some registers in order to activate SSE

mov EAX, CR4
or EAX, 600h
mov CR4, EAX
mov EAX, CR0
and EAX, 0FFFFFFFBh
or EAX, 2
mov CR0, EAX

;......

mov EAX, 2000h            ;base address for PML4
mov ECX, EAX
add ECX, 4096
mov EDX, ECX
shl EDX, 12                   ;Here I ignore upper bits of dirrection, because tables is below 1MB
or EDX, 1
or EDX, 2
mov [DS:EAX], EDX      ;DS:EAX == 0+EAX
add EAX, 4
mov EDX, 0
mov [DS:EAX], EDX
add EAX, 4
fill_PML4:
    mov dword [DS:EAX], 0
    add EAX, 4
    mov dword [DS:EAX], 0
    add EAX, 4
    cmp EAX, ECX
jne fill_PML4                  ;Here EAX keep the base for the next table

mov EDX, EAX
add EAX, 4096
mov ESI, EAX
mov ECX, EAX
shl ECX, 12
or ECX, 1
or ECX, 2
mov [DS:EDX], ECX
add EDX, 4
mov ECX, 0
mov [DS:EDX], ECX
add EDX, 4
fill_PDPT:
    mov dword [DS:EDX], 0
    add EDX, 4
    mov dword [DS:EDX], 0
    add EDX, 4
    cmp EDX, ESI
jne fill_PDPT

mov dword [DS:EDX], 83h
add EDX, 4
mov dword [DS:EDX], 0
add EDX, 4
mov EDI, 511
fill_PD:
    mov dword [DS:EDX], 0
    mov EDX, 4
    mov dword [DS:EDX], 0
    add EDX, 4
    dec EDI
    cmp EDI, 0
jne fill_PD

mov EAX, 2000h
shl EAX, 12
mov CR3, EAX

mov EAX, CR4
or EAX, 32
mov CR4, EAX

mov ECX, 0C0000080h
rdmsr
or EAX, 100h
wrmsr

;At this point work

mov EAX, CR0
or EAX, 80000000h
mov CR0, EAX                  ;Here restart

Code: Select all

mov EAX, 2000h            ;base address for PML4
mov ECX, EAX
add ECX, 4096
mov EDX, ECX
shl EDX, 12                   ;Here I ignore upper bits of dirrection, because tables is below 1MB
or EDX, 1
or EDX, 2
mov [DS:EAX], EDX      ;DS:EAX == 0+EAX

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mov EAX, 2000h            ;base address for PML4
mov ECX, EAX         ; ecx is also 0x2000
add ECX, 4096        ; ecx is now 0x3000
mov EDX, ECX         ; edx is also 0x3000
shl EDX, 12             ; Now edx is 0x3000000 ! Is that correct ?      ;Here I ignore upper bits of dirrection, because tables is below 1MB
or EDX, 1              
or EDX, 2                ; Finally edx is 0x3000003, shouldn't it be 0x3003 ?
mov [DS:EAX], EDX      ;DS:EAX == 0+EAX