MISRA Discussion Forums
Which rule of MISRA C:2012 matches rule 13.3 of MISRA C: 2004 - Printable Version

+- MISRA Discussion Forums (https://forum.misra.org.uk)
+-- Forum: MISRA C (https://forum.misra.org.uk/forumdisplay.php?fid=4)
+--- Forum: MISRA C:2004 to MISRA C:2012 migration (https://forum.misra.org.uk/forumdisplay.php?fid=155)
+--- Thread: Which rule of MISRA C:2012 matches rule 13.3 of MISRA C: 2004 (/showthread.php?tid=1300)

Which rule of MISRA C:2012 matches rule 13.3 of MISRA C: 2004 - Qiong - 14-12-2016

MISRA C: 2004 has Rule 13.3 (required): Floating-point expressions shall not be tested for equality or inequality.

This rule is very useful. We use Mathworks/Polyspace for static analysis. We can find issues of (floating variable == or != 0.0) by turning on MISRA C: 2004, but we miss this check by using MISRA C:2012.

We want to always apply the latest MISRA C standard, but not sure which rule in MISRA C: 2012 matches rule 13.3 of MISRA C: 2004?

Re: Which rule of MISRA C:2012 matches rule 13.3 of MISRA C: 2004 - dg1980 - 15-12-2016

Qiong Wrote:MISRA C: 2004 has Rule 13.3 (required): Floating-point expressions shall not be tested for equality or inequality.

This rule is very useful. We use Mathworks/Polyspace for static analysis. We can find issues of (floating variable == or != 0.0) by turning on MISRA C: 2004, but we miss this check by using MISRA C:2012.

We want to always apply the latest MISRA C standard, but not sure which rule in MISRA C: 2012 matches rule 13.3 of MISRA C: 2004?

https://misra.org.uk/forum/viewtopic.php?f=241&t=1256

Re: Which rule of MISRA C:2012 matches rule 13.3 of MISRA C: 2004 - Qiong - 15-12-2016

The information is really useful. Thank you.
dg1980 Wrote:
Qiong Wrote:MISRA C: 2004 has Rule 13.3 (required): Floating-point expressions shall not be tested for equality or inequality.

This rule is very useful. We use Mathworks/Polyspace for static analysis. We can find issues of (floating variable == or != 0.0) by turning on MISRA C: 2004, but we miss this check by using MISRA C:2012.

We want to always apply the latest MISRA C standard, but not sure which rule in MISRA C: 2012 matches rule 13.3 of MISRA C: 2004?

https://misra.org.uk/forum/viewtopic.php?f=241&t=1256


Re: Which rule of MISRA C:2012 matches rule 13.3 of MISRA C: 2004 - misra-c - 03-02-2017

Floating-point arithmetic is inherently implementation-defined, which is covered by:
Quote:Directive 1.1 Any implementation-defned behaviour on which the output of the
program depends shall be documented and understood
The https://misra.org.uk/forum/viewtopic.php?t=1256 document on MISRA-C:2004 to MISRA C:2012 mappings states
Quote:Focussing on one aspect of floating-point arithmetic (as in MISRA C:2004 Rule 13.3) attached too much importance to that aspect and might give users a false sense of confidence.