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.
