Documentation on 0xcfe IO port?

[Wallace I. Kroeker]

Hello Ron,

You put up the following code and I am wondering about the CFE port, in
particular where is there some documentation on this.

generic_init: PORT_80 0xd0
; now the fun begins.
; turn on the dram and wait a while (this from the intel book)
        mov dx, 0xcf8
        mov eax, 0x80000074
        out dx, eax
        mov dx, 0xcfe
; turn power and and set the nop bit too.
        mov al, 0x30
        out dx, al

I have the interrupt and port information from Ron Brown and there is a
reference to PORT 0CF8-0CFF as being used for PCI Configuration Mechanism 1.
When I look through all the Intel documentation I only see 0CF8 and 0CFC
referenced.  Do you have some more documentation on this?

Thanks
Wallace
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[Ronald G. Minnich]

On Wed, 16 Feb 2000, Wallace I. Kroeker wrote:
> ; turn on the dram and wait a while (this from the intel book)
>         mov dx, 0xcf8
>         mov eax, 0x80000074
>         out dx, eax
>         mov dx, 0xcfe

Yeah, this is cute. Basically you put a word-aligned address in cf8. Then
to get to reg. 76 you do an out to 0xcfe, which offsets the 74 to 76.

Look in the ALI chipset directory in openbios: they have a nice macro
there that shows how this works.

ron

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