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. > >
