Hello! W dniu 2011-01-30 19:43, Michał Pleban pisze: > But I observed, that memory corruption does not happen until we start executing this instruction: > > F000:F0BD mov al, 44h > F000:F0BF out 21h, al > F000:F0C1 nop > > This instruction is a signal to the *6509* to start sending reply bytes. > When it is executed, memory corruption happens. Why this particular > instruction? I have no idea... :-( Coincidentally, when 8088 is executing these instructions, 6509 is just around this code: $FDA0 jsr $FDEE which has $A1 as the address of one of its bytes. Until then, no kernal instruction is executed from $xx21 nor $xxA1 locations when handling the IPC call. Maybe the coexistence of $A1 on the 6509 bus and $21 on the 8088 causes the problem? But that's just pure voodoo... Regards, Michau. Message was sent through the cbm-hackers mailing listReceived on 2011-01-30 22:00:19
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