calculating program segment execution speed?

Jed

Is there a list of how many clock cycles each PBASIC command ends up taking? I'm trying to calculate the time it will take for a specific segment of code to execute. I know I can probably figure it out by trial and error but it would be nice if I could just calculate it somehow. Possible?

Zoot

Because the Stamp uses an interpreter, and raw compiled code, it's hard to think of (or calculate) times in terms of clock cycles or "instructions" -- Pbasic statements are not instructions per se.

That said, if you are looking for some pretty good estimates on actual times for setting up and executing some common Pbasic commands, see Dr. Tracy Allen's notes on the subject here: emesystems.com/BS2speed.htm

I will also add as a matter of programming style, that while you can not achieve true time regularity like you could with an SX or the like, it does help to keep times more consistent by using structures that *always* evaluate in some fashion -- rather than IF/THEN and similar statements. Example:

ioByte = ioByte MIN 1 - 1 ' this always take approx. same amount of time to execute

IF ioByte > 0 THEN          ' this takes different amount of time depending on how ioByte > 0 evaluates
   ioByte = ioByte - 1       ' additionally you will find this actually takes a LOT more code space than you would think
ENDIF                             ' compared to the above

' here's another one:

dur = dur + 1
LOOKUP dur.BIT1 ^ ioByte.BIT0, [noparse][[/noparse] ioByte, ioByte + 1 MAX $F ], ioByte

' equals:

dur = dur + 1
IF dur.BIT1 <> ioByte.BIT0 AND ioByte < $F THEN
    ioByte = ioByte + 1
ENDIF

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
When the going gets weird, the weird turn pro. -- HST

1uffakind.com/robots/povBitMapBuilder.php
1uffakind.com/robots/resistorLadder.php