Re: Parse Hex into signed number with streamdevice?

["Zimoch, Dirk via Tech-talk" <tech-talk at aps.anl.gov>]

Hello Eddy

I have implemented your request. See latest commit 5ae38a08.
https://urldefense.us/v3/__https://github.com/paulscherrerinstitute/StreamDevice/commit/5ae38a08__;!!G_uCfscf7eWS!cAw9XzrsbzJkeIaTJbCHGITiBrLKBpAF9UPGNJsfAFSd7i_i4yL_A9_NL8SDU87mR-hs6DRqHgTTqdb0ORwuRDxFFQ$ 

Now, if using the + flag ("%+x" or "%+X"), the value will be interpreted as a
signed hex number. That means it will be sign extended if the most significant
hex digit is 8 or higher. But if width is given, width characters must have been
read:

in "%+x";  sign extends "80", " 9", "0xf", "abcd" but not "0x0f" or "0fed"
in "%+4x"; sign extends "abcd" and "0xf0" but not "abc" or "0xf"

Dirk


On Mon, 2025-09-15 at 10:28 +0200, Zimoch Dirk wrote:
> Hello Eddy
> 
> Signed %x input is currently not supported by StreamDevice but it is definitely
> useful to have. I have to think how to implement it and which flag to use to
> signal the switch from normal unsigned %x.
> 
> Dirk
> 
> On Mon, 2025-09-15 at 08:04 +0000, Blomley, Edmund (IBPT) via Tech-talk wrote:
> > Hey,
> >  
> > So my device sends me a 4 bit hex which I convert to a float using an ai record and linear conversion with ESLO.
> > Let’s ignore the conversion for now, the number needs to be treated as a signed long, so I need to get the 2’s complement:
> >  
> > 07D0 -> 2000
> > F6F5 -> -2315
> >  
> > Is there a way to do this directly with streamdevice?
> > If not, I would need to read in the raw long and convert it myself. What is the best approach to do the conversion with records?
> > So far I would do:
> >  
> > field(CALC, "65535 - A + 1") with A being the raw long.
> > Cheers
> > eddy
> >