testbios and the system timer

Richard Smith rsmith at bitworks.com
Tue Jun 8 09:29:00 CEST 2004

Eric W. Biederman wrote:

>>You can in the emulator redirect I/O port access to a function. Write the 
>>code to handle read/write on those ports and use the emulate_counter to 
>>drive the clock value.
> Let me ask this quick question.  Does the emulator restrict port I/O to
> just the resources on a particular VGA device?   If not that is something
> we need to do to implement to ensure we flush these kinds of issues
> into the open and ensure the emulator is portable.

No. It allows full access to all IO ports. Otherwise it would have never 
been able to get to the system timer.

So not only will it have to emulate x86 instructions it will have to 
emulate some of the generic x86 hardware setup.

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