[ipxe-devel] 486 with a Realtek 8139

Geert Stappers stappers at stappers.nl
Sat May 8 06:45:29 UTC 2021

On Sat, May 08, 2021 at 04:03:50AM +0300, Nikolai Zhubr wrote:
> Hi all,
> I've finished with the subject successfully.

Yeah   \o/   \o/    \o/    chear

> What I've done is using prot_to_real implementation in current iPXE, I tried
> to mimic it as much as possible in respective place in Etherboot.

"in Etherboot", so not in iPXE.

> That is:
> - use ljmp instead of lret (after cr0 change);
> - assign ss and esp explicitely after that;
> - assign all other segment registers explicitely.
> Then Etherboot works fine on 486.
> So iPXE's implementation is likely correct and supposedly it should work
> too, as soon as all 586 opcodes are eliminated or handled carefully as
> discussed previously. However my brain has pretty much exploded already
> so I'm not going into more testing for now.
Any chance in dumping somewhere
a rough / rude version of the made changes?

Same request in other words:
Relief yourself from any quality demand and share you iPXE i80486 version.[1]

> Thank you,

Thank you for keeping us posted
and especially on reporting "problem solved"[2]

> Regards,
> Nikolai

Geert Stappers

[1] I volunteer for converting "Here is my version" in a "git formatted
    patch".  Feel free to contact me off-list.
[2] I wish more people do that.
Silence is hard to parse

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