Micro-GMP

[Vincent Lefevre]

On 2018-11-30 07:43:40 +0100, Marco Bodrato wrote:
> I looked at the code and I'd suggest a couple of simpler implementations:
> 
> mpz_set_si (mpz_t r, signed long int x)
> {
>   if (x >= 0)
>     mpz_set_ui (r, x);
>   else /* (x < 0) */
>     {
>       mpz_set_ui (r, GMP_NEG_CAST (unsigned long int, x));
>       mpz_neg (r, r);
>     }
> }

What is the purpose of GMP_NEG_CAST

#define GMP_NEG_CAST(T,x) (-((T)((x) + 1) - 1))

instead of just a cast followed by a negation? i.e.

  mpz_set_ui (r, - (unsigned long int) x);

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Vincent Lefèvre <vincent at vinc17.net> - Web: <https://www.vinc17.net/>
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