[Qemu-devel] Re: [PATCH] Fix extlh instruction on Alpha

[Andreas Schwab]

Vince Weaver <address@hidden> writes:

> The code is attempting the following:
>
>   tmp1=rb&0x7;
>   tmp1=temp1<<3;
>
>   if (tmp1!=0) {
>      tmp1=64-tmp1;
>      rc=ra<<tmp1;
>   }
>   else {
>      rc=ra;
>   }
>
> The problem with the original code is that in the case of tmp1 being 0,
> the shift left by 64 would result in 0, instead of the identity.
>
> I tried to avoid the jump but couldn't.  Am I missing something?

Instead of tmp1 = 64 - tmp1 use tmp1 = -tmp1 & 0x3f.

Andreas.

-- 
Andreas Schwab, address@hidden
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