yah I was surprised to see it in use. the 0MENU software from PG designs used it. don't know why. Doesn't a MOV command set flags in general also?
anyhow, I'm sure it is a rare occurance. On Mon, May 2, 2016 at 6:58 PM, Ken Pettit <[email protected]> wrote: > Really? Something uses "MOV A,A". It's just a NOP. Who would have > thought. > > Ken > > > On 5/2/16 3:56 PM, Stephen Adolph wrote: >> >> I know there is software that uses the mov a,a etc codes. we'd have >> to rework anything that glitched - or have a flag that enables >> extended op codes. >> >> On Mon, May 2, 2016 at 6:24 PM, Ken Pettit <[email protected]> wrote: >>> >>> Thanks! Not that I've seen, and I have the M100 ROM about 50% commented >>> at >>> this point (as you already know). >>> >>> But even if they did, it would only be one or two places, and those could >>> be >>> worked around. I already had to make changes to the ROM for the ISR >>> routines to perform a LRET (long return) anyway. >>> >>> Not only do I have Verilog code for the extended 8085, I also have the >>> LCD >>> controllers, Clock chip, a keyboard scanner, 8155, UART, RAM and a SPI >>> interface. Plus a top level wrapper that pulls it together as a system >>> (currently that file is called model401.v in my RTL directory). >>> >>> Ken >>> >>> >>> On 5/2/16 3:18 PM, John R. Hogerhuis wrote: >>> >>> >>> >>> On Mon, May 2, 2016 at 3:01 PM, Ken Pettit <[email protected]> wrote: >>>> >>>> I used the MOV A,A MOV B,B, MOV C,C, etc. opcodes and remaped them. >>> >>> >>> Clever! As you know though there's all kinds of strange code in the ROM >>> used >>> in "byte fighter" techniques where the programmer coded a jump into the >>> middle of an instruction effectively creating multiple entry points into >>> the >>> same instruction with different outcomes depending on the entry point. >>> Did >>> Bill ever use those opcodes as "special no-ops"? >>> >>> -- John. >>> >>> >
