andros/emacs-gpu
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity Actions

Optimize smallish mpz to native int conversion

Browse source 
* src/bignum.c (make_integer_mpz, mpz_to_intmax):
If FASTER_BIGNUM, optimize the common case where the value fits in
long int.  In this case we can use mpz_fits_slong_p and mpz_get_si
instead of looping with mpz_getlimbn.
(mpz_to_uintmax): Likewise for unsigned long int and mpz_get_ui.
This commit is contained in:
Paul Eggert 2024-07-11 12:42:57 +02:00
parent 1c8e64a953
commit 0c850df888
1 changed files with 33 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
src/bignum.c
View file

@ -145,9 +145,19 @@ make_neg_biguint (uintmax_t n)
Lisp_Object
make_integer_mpz (void)
{
if (FASTER_BIGNUM && mpz_fits_slong_p (mpz[0]))
{
long int v = mpz_get_si (mpz[0]);
if (!FIXNUM_OVERFLOW_P (v))
return make_fixnum (v);
}
size_t bits = mpz_sizeinbase (mpz[0], 2);
if (bits <= FIXNUM_BITS)
if (! (FASTER_BIGNUM
&& FIXNUM_OVERFLOW_P (LONG_MIN)
&& FIXNUM_OVERFLOW_P (LONG_MAX))
&& bits <= FIXNUM_BITS)
{
EMACS_INT v = 0;
int i = 0, shift = 0;
@ -216,6 +226,17 @@ mpz_set_uintmax_slow (mpz_t result, uintmax_t v)
bool
mpz_to_intmax (mpz_t const z, intmax_t *pi)
{
if (FASTER_BIGNUM)
{
if (mpz_fits_slong_p (z))
{
*pi = mpz_get_si (z);
return true;
}
if (LONG_MIN <= INTMAX_MIN && INTMAX_MAX <= LONG_MAX)
return false;
}
ptrdiff_t bits = mpz_sizeinbase (z, 2);
bool negative = mpz_sgn (z) < 0;
@ -246,6 +267,17 @@ mpz_to_intmax (mpz_t const z, intmax_t *pi)
bool
mpz_to_uintmax (mpz_t const z, uintmax_t *pi)
{
if (FASTER_BIGNUM)
{
if (mpz_fits_ulong_p (z))
{
*pi = mpz_get_ui (z);
return true;
}
if (UINTMAX_MAX <= ULONG_MAX)
return false;
}
if (mpz_sgn (z) < 0)
return false;
ptrdiff_t bits = mpz_sizeinbase (z, 2);