On Tue, Sep 19, 2000 at 02:58:01AM -0700, Jeremy Higdon wrote:
> Hello,
> 
> I'm using a 64 bit variable in a switch statement.  Gcc is generating code
> which make calls to __ucmpdi2, a function defined in libgcc.  I figured
> out that it was the switch statement from examining the generated code.
> 
> The question is whether I should change C code to avoid constructions
> which make calls to this routine (a little hard to determine a priori)
> or if there is an appropriate way to add this to the kernel.

        Yes do change it.

        Is the value-space for the case's a LONG LONG, or
        mere set of INTs or LONGs ?

        Can you simply (and reliably) cast the variable
        into e.g. 'long' ?  Or should you use  if / else if / ..
        chains ?

> Best I can tell, __ucmpdi2 takes two 64 bit unsigned args, returning
> 0 if the 1st arg is less than the 2nd, 2 if greater, 1 if equal.  For
> now, I have defined the function in my driver with those semantics.
> For obvious reasons, I don't consider this a viable long term option.
> 
> thanks
> jeremy

/Matti Aarnio
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