[hatari-devel] Adding cache support for the MegaSTE

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

Hi

I'm working on adding support for the MegaSTE cache in Hatari

To do so I need to use the correct number of cpu cycles for read access 
when the data is already stored in the external 16 KB cache.

It will fill 16 KB of consecutive memory to be sure the cache is full 
and then it will read this 16 KB region of memory.

Total time is measured in number of HBL (312 per VBL at 50 Hz), which is 
accurate enough to see how the cache is behaving.

for example (values are not the correct ones) :


Number of HBL per test to read 16 KB :
  8 MHz, no cache : $019e
 16 MHz, no cache : $00b4
 16 MHz, cache W/R words : $00b4
 16 MHz, cache W bytes - R bytes : $0169
 16 MHz, cache W bytes - R words : $00b4



As I don't have a MegaSTE, could someone run the attached program on his 
MegaSTE ? You should run it 2 or 3 times to be sure, but values should 
be rather stable.

program should be run in low or med res, not high res (to count HBL)

Nicolas

Attachment: mste_cac.prg
Description: Binary data