smf wrote: > It would be good if you could claim the memory after dos has loaded, using a tsr. Although memory handling is quite primitive in dos 1.25, you should get some clues from. The problem with TSRs is that they are loaded from the bottom, and we need to claim memory from the top. The only way to do it is IMHO to hack the MS-DOS kernel, maybe it's as simple as > The way to solve that issue is to have a timer irq on the 8088 that > compares the screen to a previous copy and calls the 6509. Yes, but where would that interrupt come from? Let's see at the schematic... ... and it looks like the 8259A has line IF7 connected to the TOD clock. So we *can* have periodical interrupt on the 8088. This starts to be interesting. > Dropping the memory to 192kb of ram gives you 64k of ram, which gives > you plenty. I am pretty sure that DOS eats less than 128 kB of memory. I remember that my TSR loads at segment 477, which would mean that DOS uses up only 18 kB? Regards, Michau. Message was sent through the cbm-hackers mailing listReceived on 2017-10-09 14:00:08
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