On Fri, 15 Nov 2002, Scott Dattalo wrote:

> I'm glad to see another Open Source Simulator for PICs. You may wish to
> post this to the gnupic mailing list too. Even if you don't care to merge
> your work with the GNUPIC project, I'm sure there is someone there who
> would be interested in either trying your version out or perhaps porting
> some feature of gpsim to picemu or vice-versa.

OK, I will.

>                                               Incidently, if you want to
> speed the execution up from 3Mips to 30Mips like gpsim then try statically
> decoding the source. Then create an array of pointers to the statically
> decoded instructions. The index into this array can be the program
> counter. Then you can do something like:
>
>  while( no break point) {
>
>    decode_instructions[program counter] -> decoded_instruction();
>
>  }
>
>   I.e. call the decoded instructions through the pointers.

While I'm not statically decoding the program (PICEMU is small memory
model, max of 64K code and 64K data, so I have to make some tradeoffs),
I'm already doing something like that:

   ...
   opcode = memory[ip & MEMORY_MASK];
   ip = (ip + 1) & MAX_MEMORY_MASK;
   regs[PCL] = ip;
   filenum = opcode & REGINDEX_MASK;
   dest = opcode & DEST_MASK;
   (*picops[opcode >> OPTYPES_SHIFT])();
   ...

Most of the exection time is spent updating timers, capture/compare,
PWM's, interrupts, EEPROM timings, FLASH write timings, and whatnot.

> --
> Even if you don't wish to port to Linux or windows, you may want to
> consider using MinGW. It'll run under dos (or MSys).

I've had one user talk aboug using the FTLK cross-platform GUI.  Are
they in the same ballpark?

Bill

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body