Re: [Sdcc-user] unsigned long support for PIC18F4550 ?

[Richard G. <ri...@re...>]

I am guessing a bit, but try:-

STEPPER.brakeDistance = (unsigned long)
((STEPPER.maxSpeed+STEPPER.minSpeed)*(STEPPER.maxSpeed-STEPPER.minSpeed))/(2*STEPPER.acceleration);

Of course, you could declare all the relevant variables unsigned longs and not 
bother with the cast.

FWIW, I have had trouble with code like this because the libraries are not 
reentrant and when interrupts are involved things went quite weird, but that 
was Z80 code...?

I'm not familiar with the PIC in question, but are you sure a long is 
as 'long' as you think it is!?

On Sunday 18 January 2009 10:49:45 Kustaa Nyholm wrote:
> Hi,
>
> a bit early to ask this but it may take a few hours before I can
> actually see what values I'm getting
> (my usart/serial port is not functioning at the moment) so I might as
> well ask here.
>
> Is there something to I need to do to enable support for 32 bit arithm
> ops?
>
> It appears that the following statement:
>
> STEPPER.brakeDistance = ((unsigned
> long)(STEPPER.maxSpeed+STEPPER.minSpeed))*(STEPPER.maxSpeed-STEPPER.minSpee
>d)/(2*STEPPER.acceleration);
>
> does not produce what I would expect.
>
> With the following values
> maspeed = 5000
> minspeed = 300
> acceleration = 10000
>
> this should give
>
> breakDistance = 1245
>
> but judgin from the behavior of the motors this is not happening. If I
> manuallu put in the correct breakDistance then this works.
>
> Yeah, would be better if I had some actual faulty values to show, but
> that will take some hours..or days.
>
> Meanwhile, anything obvious in my code?
>
> Do I need to recompile SDCC libraries or some such?
>
> br Kusti
>
<snip>

-- 
Richard.
PGP Key-id: 0x5AB3D350

George Orwell was an optimist.