"Hamish Guthrie \(Mail Lists\)" <[EMAIL PROTECTED]> writes:
> Ron,
>
> There is no other way for me to implement an efficient timer for Etherboot
> other than to implement it with interrupts. There is however another point
> to consider - it would only make sense to have interrupts implemented on 486
> and lower processors in this instance because of their lack of tsc. In all
> of these platforms, there are only legacy i8259 type PIC's so we do not need
> to concern ourselves with APIC's etc.
>
> I actually now have done an implementation in LinuxBIOS and the clock tick
> works great - I have done Eric's elf loader trick and used the .ebi image
> from etherboot (unfortunately I have to make a small mod to etherboot code -
> basically leaving re-enabling interrupts and looking at 0040:006c for the
> timer tick.
>
> Everythin seems rosy, but for some stupid reason - on the only ehternet
> cards I have (various tulip based ones and Realtek) - there is a transmit
> timeout - no joy yet but I am trying to figure out what is going on.
O.k. Here is what I suggest. Setting up an interrupt descriptor table
in linuxbios so we can handle interrupts if we want is fine. But...
I would only use this to catch exceptions in linuxBIOS and as a piece
of example code. So people who need to do it can copy what is linuxBIOS.
If you can modifiy linuxBIOS to cause interrupts you should be able to make
the same modifications to etherboot. The advantage to makeing them in
etherboot is that you (or someone else) can then run etherboot under a
normal BIOS and still have the same code running so debugging becomes
easier. In particular the normal etherboot developers will be able to
reproduce your problems...
Eric
