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Index > OS Construction > 64 bit IA32_EFER.LME

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lazer1



Joined: 24 Jan 2006
Posts: 185
lazer1
I'm attempting to boot to 64 bit code,

the Intel vol3 Ch9.8.5 says for one of the
steps I have to set the LME bit of
the IA32_EFER register,

the LME bit being bit 8,

I tried:

Code:
use32
    mov ebx,ia32_efer
    or ebx,100h             ; set bit 8,
    mov ia32_efer,ebx
    


but fasm appears not to recognise this,

the AMD64 docs seem to refer to the register as EFER,
I tried that also and fasm also doesnt recognise it, Mad


any suggestions? Surprised
Post 22 Mar 2006, 16:31
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vid
Verbosity in development


Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia
vid
i believe mazegen will have an answer Smile

he is walking/living intel manual Wink
Post 22 Mar 2006, 16:51
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FlashBurn



Joined: 06 Jan 2005
Posts: 87
FlashBurn
The IA32_EFER register is an msr (model specific register) and you have to use rdmsr and wrmsr for that!

Code:
mov ecx,0xC0000080
rdmsr
or eax,100h
wrmsr
    
Post 23 Mar 2006, 12:26
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lazer1



Joined: 24 Jan 2006
Posts: 185
lazer1
FlashBurn wrote:
The IA32_EFER register is an msr (model specific register) and you have to use rdmsr and wrmsr for that!

Code:
mov ecx,0xC0000080
rdmsr
or eax,100h
wrmsr
    


fasm accepts that Razz

I'll resume from where I left off Arrow

a lot left to do Sad
Post 25 Mar 2006, 00:56
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