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flat assembler > DOS > How to temporary modify BIOS

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CandyMan



Joined: 04 Sep 2009
Posts: 269
Location: film "CandyMan" directed through Bernard Rose OR Candy Shop
Code:
; Example how to temporary modify video BIOS and enable high resolution modes on my NVIDIA GeForce 9600 GSO 512 org 100h Start: cli call ChipsetOpen mov ax,0xC000 mov fs,ax mov word [fs:4695h],0xC3F8 ;clc / ret - all modes as valid for this monitor call ChipsetClose sti ret ChipsetOpen: mov ecx,0xC0010010 rdmsr mov [xC0010010+0],eax mov [xC0010010+4],edx or eax,80000h wrmsr mov ecx,268h rdmsr mov [xC000+0],eax mov [xC000+4],edx inc ecx rdmsr mov [xC800+0],eax mov [xC800+4],edx inc ecx rdmsr mov [xD000+0],eax mov [xD000+4],edx inc ecx rdmsr mov [xD800+0],eax mov [xD800+4],edx inc ecx rdmsr mov [xE000+0],eax mov [xE000+4],edx inc ecx rdmsr mov [xE800+0],eax mov [xE800+4],edx inc ecx rdmsr mov [xF000+0],eax mov [xF000+4],edx inc ecx rdmsr mov [xF800+0],eax mov [xF800+4],edx mov ecx,268h mov eax,18181818h mov edx,eax wrmsr ; C000-C7FF inc ecx wrmsr ; C800-CFFF inc ecx wrmsr ; D000-D7FF inc ecx wrmsr ; D800-DFFF inc ecx wrmsr ; E000-E7FF inc ecx wrmsr ; E800-EFFF inc ecx wrmsr ; F000-F7FF inc ecx wrmsr ; F800-FFFF ret ChipsetClose: mov ecx,268h mov eax,[xC000+0] mov edx,[xC000+4] wrmsr inc ecx mov eax,[xC800+0] mov edx,[xC800+4] wrmsr inc ecx mov eax,[xD000+0] mov edx,[xD000+4] wrmsr inc ecx mov eax,[xD800+0] mov edx,[xD800+4] wrmsr inc ecx mov eax,[xE000+0] mov edx,[xE000+4] wrmsr inc ecx mov eax,[xE800+0] mov edx,[xE800+4] wrmsr inc ecx mov eax,[xF000+0] mov edx,[xF000+4] wrmsr inc ecx mov eax,[xF800+0] mov edx,[xF800+4] wrmsr mov ecx,0xC0010010 mov eax,[xC0010010+0] mov edx,[xC0010010+4] wrmsr ret xC000 dd ?,? xC800 dd ?,? xD000 dd ?,? xD800 dd ?,? xE000 dd ?,? xE800 dd ?,? xF000 dd ?,? xF800 dd ?,? xC0010010 dd ?,?

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Post 11 Nov 2015, 18:24
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