Re: [hatari-devel] Many changes to MFP

[Nicolas Pomarède <npomarede@xxxxxxxxxxxx>]

On 14/03/2013 10:10, Eero Tamminen wrote:
> Hi,
>
> On torstai 14 maaliskuu 2013, Nicolas Pomarède wrote:
> > For now, MachineClocks.CPU_Freq is not really used, it's just
> > informative. You also need to check if cpu freq is 8,16 or 32 (using the
> >
> >   >> operator to divide cycles by 2 or 4). No clean solution for now, it
> >
> > can be solved latter as it doesn't impact emulation itself. Add a
> > special case for the TT if you need in your code.
>
> Do you mean that CPU cycles are always counted using 8Mhz clock,
> not the one at which the CPU is running at?

Yes, in a all cores/all cpu, cpu freq is always assumed to be 8 MHz 
(this is required to keep a constant ratio with other component like 
FDC, ACIA, ...).
The effective 16 or 32 MHz freq is obtained by dividing each 
instruction's cycles by 2 or 4 :

static inline void M68000_AddCycles(int cycles)
{
        cycles = (cycles + 3) & ~3;
        cycles = cycles >> nCpuFreqShift;
...
}