Just in case you find it absolutely essential to perform floating
point calculations within an Interrupt Service Routine - on Vxworks
(as inadvisable as that may be)
FP_CONTEXT fp_context;
(void) fppSave (&fp_context);
<your ISR code here>
(void) fppRestore (&fp_context);
AH
> Date: Fri, 27 Feb 2004 16:22:53 -0600
> From: Eric Norum <[email protected]>
>
> D. Peter Siddons wrote:
> > Thanks to all who responded. I should have made it clear that I was
> > talking about an RTEMS app., which only has
> > epicsInterruptContextMessage(), which can only print a string, no
> > formatting. Eric Norum suggested using snprintf() to fill a buffer and
> > pass that to epicsInterruptContextMessage(). That seems to work fine. I
> > had the impression before that calling any of the xprintf() commands
> > from within interrupt context wasn't allowed, but apparently the string
> > variants are OK.
> > Pete.
> The string variants can't ever block so they're safe to call from an interrupt
> handler -- with one small caveat. Interrupt handlers typically do not have
> their own floating point context so you've got to ensure that snprintf does
> not execute any floating-point instructions.
>
> --
> Eric Norum [email protected]
> Advanced Photon Source Phone: (630) 252-4793
> Argonne National Laboratory
>
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