Hello! Mia Magnusson wrote: > Of course this would only be visible by the 6509, but it would still > make it far easier, just copy 4k of data each time the screen needs > updating. Not sure if a 4k block copy (fixed addresses both for source > and destination, and requiring ,Y indirect addressing for either source > or destination) would be too slow to just do on each interrupt. Regarding this, I already tried to check what would it require to write a screen copy routine. Generally, an IBM->PETSCII conversion requires just two additional LDA xxx,X instructions so it will not be much more difficult. Plus, you cannot run this in the interrupt, because you would need to access the RAM to copy the characters from, and you can't do that when 8088 is running. The copying must be initiated by the 8088. Regards, Michau.Received on 2018-07-12 12:00:34
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