flat assembler
Message board for the users of flat assembler.

flat assembler > OS Construction > 2MB pages in long mode and 0xB8000 address

Thread Post new topic Reply to topic

Joined: 04 Sep 2009
Posts: 269
Location: film "CandyMan" directed through Bernard Rose OR Candy Shop
How to map 0xB8000..0xBFFFF at 68GB+16MB=(0x1101000000) ?
My code is:
MaxMem dd 64 ;64GB MemoryStart dd 1024*1024 ;1M push 0 pop fs mov eax,[MaxMem] shl eax,12 lea ebx,[eax+512*8*(2+1)] mov ebp,ebx push ebx mov eax,[MemoryStart] mov ebx,eax lea eax,[ebx+4*1024-1] ;\ Align to 4*1024 and ax,not (4*1024-1) ;/ mov [PML4],eax add eax,4*1024 mov [PDP],eax add eax,4*1024 mov [PDT],eax pxor mm0,mm0 pop ecx shr ecx,3 @@: dec ecx movq [fs:ebx+ecx*8],mm0 jnz @B mov eax,[PML4] mov ebx,[PDP] mov ecx,[PDT] or bl,7 or cl,7 mov [fs:eax+8*000],ebx ;Fill page tables mov eax,[PDP] xor edx,edx .1: mov [fs:eax+8*edx],ecx add ecx,4*1024 inc edx cmp edx,[MaxMem] jb .1 mov eax,2*1024*1024 movd mm1,eax mov eax,PT_AVL+PT_PS+PT_U+PT_W+PT_P ;Start from 1st 0..2MB-1 movd mm0,eax mov ecx,[MaxMem] shl ecx,9 mov eax,[PDT] .0: movq [fs:eax],mm0 paddq mm0,mm1 add eax,8 loop .0 mov eax,[AddrLFB] or eax,eax jz @F or eax,PT_AVL+PT_PS+PT_U+PT_W+PT_P movd mm0,eax mov edx,[PDT] add edx,(68 shl 9)*8 mov ecx,8 .2: movq [fs:edx],mm0 paddq mm0,mm1 add edx,8 loop .2 mov eax,0xB8000+PT_AVL+PT_U+PT_W+PT_P movd mm0,eax movq [fs:edx],mm0 @@:

smaller is better
Post 02 Aug 2016, 10:39
View user's profile Send private message Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  

< Last Thread | Next Thread >

Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum

Copyright © 2004-2018, Tomasz Grysztar.

Powered by rwasa.