Re: Digest from [email protected]

Hi Mark,
Thanks for that too.  I am afraid I am mostly a 
hardware guy so this is about the
only C compiler I have right now. In the past I 
did most of my work in assembly
on the MSP430.

Which brings me to one last question if I could 
impose.  Basically what I am doing
here is capturing a pulse by a time to determine 
the pulse width.  I capture the
rising and falling edges on a counter that is modulo 16 bits.  The MSP430 is a
16-bit machine so to get the pulse width I just 
subtracted the falling edge from the
rising edge value and got a positive value.  The 
reason I went to signed shorts on
the coldfire is that I saw in the assembly it was 
loading the shorts with zero extend
and then doing a 32-bit subtract.  I don't think 
this will give me the correct value so
I went to signed shorts and it does.  You 
suggested going to unsigned shorts but
I don't think this will work.  Am I missing something simple here?   Thanks,

At 12:00 AM 9/15/2008 -0500, [email protected] wrote:
>From: "Mark Butcher" <[email protected]>
>To: <[email protected]>
>Subject: AW: [ColdFire] Re: Digest from  [email protected]
>Date: Sun, 14 Sep 2008 22:57:40 +0200
>
>Hi Bob
>Just a side note. I work with several compilers and the CW warnings are in
>fact quite extreme and I do in fact keep them off since otherwise the
>casting required also becomes rather extreme.
>My solution is to compile the project with GCC and Visual-Studio C-compilers
>and ensure that they don't give any warnings - assuming that this is the
>case, then I am satisfied.
>Regards
>Mark
>
>
>
>-----Ursprüngliche Nachricht-----
>Von: [email protected] [mailto:[email protected]] Im
>Auftrag von Robert Ritchey
>Gesendet: Sonntag, 14. September 2008 16:44
>An: [email protected]
>Betreff: [ColdFire] Re: Digest from [email protected]
>
>Hi Mark,
>Thank you very much for the detailed explanation.  Its very clear now.
>I think with this help I can make some informed decisions on how to
>declare variable types.
>
> >
> >typedef struct
> >      {
> >      short            RiseEdge;                       /* Pulse rising
> >edge time                       */
> >      short            FallEdge;                       /* Pulse
> >falling edge time                      */
> >      } ChanInStruct;
> >
> >bool TxPulseOffset(short *Offset)
> >{
> >      short   PulseWidth;
> >                     /* Pulse width                          */
> >      PulseWidth = (short)(pRxChannelInput->FallEdge -
> >pRxChannelInput->RiseEdge);        /* Pulse width is falling minus rising
>*/
> >}

-Bob
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