64 bit IA32_EFER.LME

flat assembler
Message board for the users of flat assembler.

Index > OS Construction > 64 bit IA32_EFER.LME

Author

Thread

lazer1

Joined: 24 Jan 2006
Posts: 185

lazer1 22 Mar 2006, 16:31

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

22 Mar 2006, 16:31

vid
Verbosity in development

Joined: 05 Sep 2003
Posts: 7105
Location: Slovakia

vid 22 Mar 2006, 16:51

i believe mazegen will have an answer Smile

he is walking/living intel manual Wink

22 Mar 2006, 16:51

FlashBurn

Joined: 06 Jan 2005
Posts: 87

FlashBurn 23 Mar 2006, 12:26

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

23 Mar 2006, 12:26

lazer1

Joined: 24 Jan 2006
Posts: 185

lazer1 25 Mar 2006, 00:56

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

a lot left to do Sad

25 Mar 2006, 00:56

< 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