Re: [Vice-emu-mail] X64SC Monitor, chis, unaccounted clock cycles.

Am Sonntag, 10. August 2025, 13:09:36 Mitteleuropäische Sommerzeit schrieb 
timothylegg:
> I am using x64sc 3.9 (GTK3 3.24.41, GLib 2.80.0, Cairo 1.18.0, Pango
> 1.52.1) which I'm pretty certain is compiled from source.
> 
> 
> Last week, I used chis for the cpu_history and I noticed something
> peculiar...
> 
> C:c402  A9 10       LDA #$10       A:0e X:6f Y:00 SP:d8 .V-..I.C
>  191041395
> .C:c404  9D 00 C0    STA $C000,X    A:10 X:6f Y:00 SP:d8 .V-..I.C
>  191041397
> .C:c083  48          PHA            A:10 X:6f Y:00 SP:d5 .V-..I.C
>  191041452
> .C:c084  AD 18 C0    LDA $C018      A:10 X:6f Y:00 SP:d4 .V-..I.C
>  191041455
> .C:c087  4A          LSR A          A:0e X:6f Y:00 SP:d4 .V-..I.C
>  191041459
> 
> Does anyone know why the STA (9D) take 55 clock cycles?  From the MOS
> datasheet, I see that it should be 5.  Is this a bug in the emulator or is
> there something quirky with the C64 hardware that I don't know about yet?

My guess would be that there was DMA going on ("badline" and/or sprites)


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