[LLVMdev] x86 rounding mode question

[Dale Johannesen]

On Sep 28, 2010, at 4:14 PMPDT, Bob wrote:

> Hi,
>  
> Is there a recommended way to round to the nearest whole (x86 RC field of FPU control  = 00) ?
>  
> It appears an intentional truncation instruction is generated (if ms disassembly is correct):

The description of fptosi as "converts...into the nearest (rounding towards zero)" is perhaps a little confusing.  That is actually a truncation.   No, there's no way to change rounding modes, although people keep talking about adding it.  It is not an easy thing to do.




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