RE: [avr-gcc-list] Re: C vs. assembly performance

[Weddington, Eric]

> -----Original Message-----
> From: 
> address@hidden 
> [mailto:address@hidden
> org] On Behalf Of Bob Paddock
> Sent: Sunday, March 01, 2009 6:22 AM
> To: address@hidden
> Subject: Re: [avr-gcc-list] Re: C vs. assembly performance
> 
> > And the first complies with coding standards like gnu and gcc,
> > and maybe even others like misra etc.
> 
> MISRA doesn't say a lot about style, that is how pretty
> the code looks.  It is implicit that ugly looking code
> is bad, and probably buggy.  If your code looks
> like a IOCCC entry, your code would not be MISRA
> complaint.
> http://www.ioccc.org/
> 
> Per MISRA, in a nested if/else tree all brackets are required, and
> there must be a final else{} as you showed.
> 
> As far as I can tell MISRA-2004 is silent on a preference
> between switch(), nested if/else() and function pointers.
> Personally I prefer tables of function pointers.  Makes
> code looking like a threaded language like Forth at times.
> In any case what can get hairy fast is conditionals containing
> conditionals, which makes testing all execution paths problematic.
> 
> Note that technically no AVR-LibC based project complies
> with MISRA due to rule #3.6 that says any library used,
> including the GCC libraries, must be complaint with MISRA [IEC 61508
> Part 3].  I tend to follow the MISRA Guidelines anyway as it shows an
> attempt at Due Diligence.

Bob,

s/complaint/compliant/g
They're two different words. ;-)

I would really like gcc to have a -wmisra switch someday, so we can test if an 
application, or library such as avr-libc is compliant. Not that I like MISRA 
anyway. I think it's a brain-dead standard.

But do you have some tool that you have used to check avr-libc against MISRA? 
If so, do you have a list of issues that it found?

Eric