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Message
From: Guy Hutchison<ghutchis@g...>
Date: Thu Dec 8 04:15:26 CET 2005
Subject: [oc] T80 bugfix for INI, IND, INIR, INDR, OUTI, OUTD, OTIR, OTDR
Hi Peter,We spoke a while back, and you mentioned the JR bug recently on the list. I had a little time today to look in to it, and was wondering if you could elaborate on what the bug is.
According to the Z80 handbook, the cycle timing for a JR operation is 4/3 if the test fails, and 4/3/5 if the test passes. This matches the mcycle coding in the microcode as well as the results I see in simulation.
Could you (re)summarize the problem for me?
Thanks,
Guy
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