Il 2018-12-21 19:13 ni...@lysator.liu.se ha scritto:
2. Reduce the number of places that depend on mp_limb_t == unsigned
long, where that also makes code simpler. E.g, using init_set_ui or
roinit_ui in more of the _ui functions.
Starting from the current code:
- for comparison functions (mpz_fits_slong_p, mpz_fits_ulong_p,
mpz_cmp_si, mpz_cmp_ui, but also mpz_set_si), unconditionally using the
if (GMP_LIMB_BITS < GMP_ULONG_BITS) branch and remove the following
ones, should be enough;
- for arithmetic functions (mpz_add_ui, mpz_mul_ui, mpz_div_qr_ui), we
can remove all the code but the content of the branch if (value >
GMP_LIMB_MAX);
- for mpz_gcd_ui (should we change also mpz_lcm_ui?) the code you
proposed a couple of weeks ago is better, moreover you proposed to
remove mpn_div_qr_1 and to adapt also mpz_addmul_ui and mpz_submul_ui,
should be done;
- for power computations (mpz_ui_pow_ui, mpz_powm_ui) we can keep only
the branch with init_set.
I can start with this.
Then, the functions with special code for the p_limb_t != unsigned long
case will be only five: gmp_umul_ppmm, mpn_invert_3by2, mpz_get_ui,
mpz_set_ui, and mpn_absfits_ulong_p.
The last one is used (directly or not) by all comparison functions, and
reduces to a static {return un <= 1;} in the typical case.
The first two (gmp_umul_ppmm, mpn_invert_3by2) has special code for
speed only. The compiler can choose the one to be used at compile time.
If you add also roinit_ui, there will be six, but maybe it will be worth
rewriting mpz_set_ui to use it...
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