Re: [hatari-devel] rev 3689 : splitting cpu cycles above 20

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On 07/01/2012 12:00, Laurent Sallafranque wrote:

Then, I'd like to have a look at the videl.
My aim would be to :
1) have a working videl (HBL, VBL, TIMERS, correct display, "Rasters
:)", ...)
2) be able to use the videl "bean position" to do precise measures (as
you do with the shifter with the Video_GetPosition(),
Video_Calculate_adress(), ... functions).

I would like to run 10 NOPs and read the beam position, then compare
with my real falcon and get the same value (or close).
Then I could measure all the instructions and verify is they're using
the good cycle timings. (10 ADD, 10 DIVS, 10 MOVEMS, ...)
(10 is an arbitrary value, it could be 1 instruction, or 1000

The same after for some crossbar exchages if necessary.

This wouls also allow to add correctly the VIDEL Waitstates.

I'm not familiar with the falcon, but given the different caches in the cpu and the different video mode, I think it might be much more complicated to read the video address in a "sync" way to measure an instruction reliabily.

(I don't even know if some falcon demos are doing "sync" code with the video beam ?)


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