From: Baltissen, GJPAA (Ruud) (ruud.baltissen_at_abp.nl)
Date: 2004-02-10 07:21:18
Hallo Nick,
> Does everyone else read it the same way?
Yep.
Hallo Rainer,
> Wasn't the problem with RDY that it needs up to 3 cycles to be
> acknowledged,
Those three cycles are needed because the VIC hasn't any idea what the CPU
is doing and therefor MUST insert them in case a IRQ is going on.
The CP/M-cartridge for example doesn't need it. The cart is activated by
setting a bit in a register that on its turn pulls the DMA-input of the
expansionport low. Assume that at that moment IRQ was triggered. The first
thing the 6510 does is pushing three bytes to the stack. But the actual
writing hasn't started yet so therefor the 6510 honours the status of RDY
and halts.
--
___
/ __|__
/ / |_/ Groetjes, Ruud
\ \__|_\
\___| URL: Ruud.C64.org
=====DISCLAIMER=================================================================
De informatie in dit e-mailbericht is vertrouwelijk en uitsluitend bestemd voor de geadresseerde. Wanneer u dit bericht per abuis ontvangt, verzoeken wij u contact op te nemen met de afzender per kerende e-mail. Verder verzoeken wij u in dat geval dit e-mailbericht te vernietigen en de inhoud ervan aan niemand openbaar te maken. Wij aanvaarden geen aansprakelijkheid voor onjuiste, onvolledige dan wel ontijdige overbrenging van de inhoud van een verzonden e-mailbericht, noch voor daarbij overgebrachte virussen.
The information contained in this e-mail is confidential and may be privileged. It may be read, copied and used only by the intended recipient. If you have received it in error, please contact the sender immediately by return e-mail; please delete in this case the e-mail and do not disclose its contents to any person. We don't accept liability for any errors, omissions, delays of receipt or viruses in the contents of this message which arise as a result of e-mail transmission.
Message was sent through the cbm-hackers mailing list
Archive generated by hypermail pre-2.1.8.