It's counterintuitive but if you want max serial port handling speed you should disable the interrupt and poll.
-- John. On Tue, Jul 1, 2025, 3:37 PM Erik Keever <[email protected]> wrote: > Hi, > > I am working on an assembly program that involves the serial port hook at > F5FC. > > The current code I have works by setting a JMP there to my data-received > handler and then just returning. > > This is fine, but so far as I can tell from disassembling the ROM handler > at 6DAC, after I return, the whole rest of the ROM's handler *also* runs. > The program doesn't execute incorrectly since I've already got the data but > I'm not suffering through writing assembly because I enjoy wasting lots of > cycles. > > Now it seemed to me that since it gets to my code by > call 0034 due to IRQ > jmp 6DAC > call F5FC (immediately at 6DAC) > jmp $mycode, > I should be able to INX SP twice to "delete" the return-to-rom address > such that when I do RET it will return from the IRQ instead, thereby > sidelining the ROM code completely. > > Except if I do this I am pointedly reminded that the 8085 does not have > protected mode. And so my question: er... what exactly am I doing wrong > here? > > -- Erik >
