Re: CPU options during config

Helge Hafting (helge.hafting@daldata.no)
Fri, 08 Jan 1999 09:10:03 +0100

> however, there remains an inconsistency between the config menu and the
> help text, which is what i was reporting in the first place. that ought
> to be addressed by someone who knows where K6 really belongs. i'm just
> guessing.
Processors ougth to be sorted by instruction set - even if gcc
don't use all instructions on new processors. It may do so
someday, and the kernel may contain processor #ifdef's with
processor-specific asm-statements.

Processors with the same instruction set may be grouped further by
what compiler optimizations they take advantage of. Optimizations
for different processors are conflicting sometimes.
>
> isn't there any way to capture a software interrupt when these new
> instructions/features are used on an old processor? i've worked on
Sure - 386 and up has a "illegal instruction" exception, but you don't
want the kernel to run emulated instructions - that's bad for performance
and a good reason for having a cpu specific setup.
You may want to provide emulations for user programs though,
floating point math is emulated for 386/486sx for example.

Helge Hafting

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