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OK, I 've been trying to enter long mode, and the program crashes when paging is set.
Here is the FASM code I use to setup the page code. I 've seen some code already, but I haven't yet managed to make it work. It crashes both Bochs and VMware. Do you notice any errors ?


PAGEORGBASE EQU 40000h
SEGMENT PAGE64 USE64
; For simplicity, put the page strutures at absolute memory 40000h, assuming it is empty.
; PAGE64 segment to hold the page
ORG PAGEORGBASE

; 4096 bytes for PML4
PML4_64 db 4096 dup (?)

; 4096 bytes of PDP
PDP_64 db 4096 dup (?)

; 4096 bytes of PD_64

PD_64 db 4096 dup (?)
;
PAGE_64 dq 4096 dup (?)
; 32768 Bytes = 4096 Pages = 4096*4096 = 16MB (Each page takes 8 bytes)



;
; Real mode code to initialize the page structures
; To provide a "see through" to the lower 16MB
;

InitPageTable64162:
; PageDirectory = PAGEORGBASE
pushad
push ds
mov eax,PML4_64
shr eax,4
mov ds,ax

xor edx,edx
; DS:DX = PML4_64

mov ecx,PDP_64
sub ecx,PAGEORGBASE
; DS:CX = PDP_64
; Put PDP to PML4
xor ebx,ebx
mov bx,cx
add ebx,PAGEORGBASE
or bl,111b ; Mark it as read/write/user
mov [ds:edx],ebx

mov ebp,PD_64
sub ebp,PAGEORGBASE
; DS:BP = PD_64
; Put PD to PDP
xor ebx,ebx
mov bx,bp
add ebx,PAGEORGBASE
or bl,111b ; Mark it as read/write/user
mov [ds:ecx],ebx

; 16MB map
mov ecx,16777216
shr ecx,12 ; Make it number of pages

; Build 4096 Pages to map 16MB of memory
; Each page takes 8 bytes

mov edi,PAGE_64
sub edi,PAGEORGBASE

;
; DS:BP = PD_64
; DS:DI = PAGE_64
;
xor esi,esi

xor ebx,ebx
mov bx,di
add ebx,PAGEORGBASE

NextPageTable:

; DS:DI holds the address of next page in memory
; EBX holds the absolute address of next page in memory
; DS:BP holds the address of the page directory entry for this page

; Put this page to page directory
PUSH EBX
or bl,111b ; Mark it as read/write/user
mov [ds:ebp],ebx
POP EBX
ADD EBX,8

ADD EBP,8

lea eax,[esi + 0111b]
; Configure this page to map memory
mov [ds:edi],eax ; Configure This Page
add edi,8 ; To next page, 8 bytes each
add esi,1000h ; Next 4096 bytes

; Are we finished doing our pages ?
dec ecx
jecxz Done

jmp NextPageTable

Done:

pop ds
popad
ret


;
; Here is the protected mode code that tries to enable long mode
;

; Enable Long Mode
mov eax, cr4
bts eax, 5
mov cr4, eax

; Load new page table
mov edx,PML4_64
mov cr3,edx

; Enable Long Mode
mov ecx, 0c0000080h ; EFER MSR number.
rdmsr ; Read EFER.
bts eax, 8 ; Set LME=1.
wrmsr ; Write EFER.

; Enable Paging to enter Compatibility Mode
mov eax, cr0 ; Read CR0.
or eax,80000000h ; Set PE=1.
mov cr0, eax ; Write CR0. BOOM !

....



Thanks a lot for any response.
Michael

I should note that Bochs says

"00185462382p[CPU0 ] >>PANIC<< PAE PDPE 0x0e53505652061ecb: Only 32 bit physical
address space is emulated !"

Does this mean I have to change some option I haven't found yet to allow 64-bit physical address space?

Regards.

Issue fixed