Re: [Axiom-developer] Left shifts of negative numbers

[Dylan Thurston]

On Tue, Oct 14, 2003 at 09:09:50PM -0400, Page, Bill wrote:
> Does
> 
>   shift(x,y) == -integer(ASH(-x,y)$Lisp
> 
> involve two (potential long) integer multiplications?
> I.e. -1*integer(ASH(-1*x,y)$Lisp

I don't know whether adding/subtracting 1 or negation will be faster,
but either one should be faster than any multiplication (unless
multiplication by -1 is special cased somewhere).  There are no carries
to worry about.

I suspect the additions are probably faster, actually.

Peace,
        Dylan

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