Experimental Physics and
Industrial Control System

What do people think of the idea of increasing the size of the CALC field
beyond 40 characters for R3.14.12?  When replying to this question, please
bear in mind that:
1. For every additional character allowed in the expression, we have to
    allocate space for up to ~5 more in the tokenized RPCL field
2. Most expressions are short, so most of the extra space will be wasted
3. We still have sites running IOCs on memory-limited micro-controllers

For those that don't know the technology, the CALC string is parsed and
compiled at record initialization time or whenever you modify the CALC field
into a string of reverse-polish binary tokens that can be executed very
efficiently.  A subroutine record would execute the expression faster, but is
not as flexible since you have to recompile and reboot the IOC to change the
expression, and that can only be done by someone who knows C and has write
access to the IOC's source tree.

- Andrew

--
Tim Mooney ([email protected]) (630)252-5417
Software Services Group, Advanced Photon Source, Argonne National Lab.

Replies:

Re: CALC expression Andrew Johnson

References:

CALC expression Andrew Wagner

Re: CALC expression Tim Mooney

Re: CALC expression Matthieu Bec

Re: CALC expression Andrew Johnson

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