mpn_neg

[Zimmermann Paul]

       Hi,

I discovered the mpn_neg function:

 -- Function: mp_limb_t mpn_neg (mp_limb_t *RP, const mp_limb_t *SP,
          mp_size_t N)
     Perform the negation of {SP, N}, and write the result to {RP, N}.
     Return carry-out.

Since mpn only deals with nonnegative numbers, what is "the negation of
{SP, N}"? Also, should the carry be a borrow?

Paul