Virtualc64: CIA/cia-timer.prg fails for new CIAs

Created on 4 Oct 2018  路  4Comments  路  Source: dirkwhoffmann/virtualc64

bildschirmfoto 2018-10-04 um 07 49 07

Priority-Medium bug
Source
picture dirkwhoffmann

All 4 comments

bildschirmfoto 2018-10-05 um 17 37 37

That was an easy one. The old CIAs (NMOS technology) are affected by a race condition which is known as "Timer B bug". It prevents the IRQ bit in the ICR register being set for timer B, if the ICR register is read at the same time. The new CIA chips (HMOS II technology) don't seem to be affected by this "bug", because disabling the bug emulation code is enough to make the VICE test pass.

dirkwhoffmann picture dirkwhoffmann on 5 Oct 2018
👍1

What am I wrong?
It does not work for me
schermata 2018-10-07 alle 10 52 18

Alessandro1970 picture Alessandro1970 on 7 Oct 2018

This test is broken now. 馃檨

dirkwhoffmann picture dirkwhoffmann on 7 Oct 2018

3.0 beta 3 should fix it:

http://www.dirkwhoffmann.de/virtualC64/VirtualC64_3.0_beta3.zip

BTW, thanks again to David Horrocks (Hoxs64). I shamelessly adapted his solution for this problem.

dirkwhoffmann picture dirkwhoffmann on 7 Oct 2018
😄1
Was this page helpful?
0 / 5 - 0 ratings

Related issues

Alessandro1970 picture Alessandro1970  路  5Comments
Somuchfun picture Somuchfun  路  3Comments
PakkunKinoppi picture PakkunKinoppi  路  4Comments
Alessandro1970 picture Alessandro1970  路  6Comments
dirkwhoffmann picture dirkwhoffmann  路  7Comments