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[bits 32]
global copy_page_physical
copy_page_physical:
push ebx ; According to __cdecl, we must preserve the contents of EBX.
pushf ; push EFLAGS, so we can pop it and reenable interrupts
; later, if they were enabled anyway.
cli ; Disable interrupts, so we aren't interrupted.
; Load these in BEFORE we disable paging!
mov ebx, [esp+12] ; Source address
mov ecx, [esp+16] ; Destination address
mov edx, cr0 ; Get the control register...
and edx, 0x7fffffff ; and...
mov cr0, edx ; Disable paging.
mov edx, 1024 ; 1024*4bytes = 4096 bytes to copy
.loop:
mov eax, [ebx] ; Get the word at the source address
mov [ecx], eax ; Store it at the dest address
add ebx, 4 ; Source address += sizeof(word)
add ecx, 4 ; Dest address += sizeof(word)
dec edx ; One less word to do
jnz .loop
mov edx, cr0 ; Get the control register again
or edx, 0x80000000 ; and...
mov cr0, edx ; Enable paging.
popf ; Pop EFLAGS back.
pop ebx ; Get the original value of EBX back.
ret
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