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(z_negative_one): New variable.

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(scm_init_numbers): Initialize it.
(scm_logcount): Use it and mpz_hamdist to count zeros for negatives.
This commit is contained in:
Kevin Ryde 2003-05-30 00:23:11 +00:00
parent 5f653c6a56
commit 713a425913
1 changed files with 7 additions and 13 deletions
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20
libguile/numbers.c
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@ -119,6 +119,7 @@ isinf (double x)
static SCM abs_most_negative_fixnum; static SCM abs_most_negative_fixnum;
static mpz_t z_negative_one;
@ -1396,20 +1397,11 @@ SCM_DEFINE (scm_logcount, "logcount", 1, 0, 0,
else if (SCM_BIGP (n)) else if (SCM_BIGP (n))
{ {
unsigned long count; unsigned long count;
if (mpz_sgn (SCM_I_BIG_MPZ (n)) < 0) if (mpz_sgn (SCM_I_BIG_MPZ (n)) >= 0)
{ count = mpz_popcount (SCM_I_BIG_MPZ (n));
mpz_t z_n;
mpz_init (z_n);
mpz_com (z_n, SCM_I_BIG_MPZ (n));
scm_remember_upto_here_1 (n);
count = mpz_popcount (z_n);
mpz_clear (z_n);
}
else else
{ count = mpz_hamdist (SCM_I_BIG_MPZ (n), z_negative_one);
count = mpz_popcount (SCM_I_BIG_MPZ (n)); scm_remember_upto_here_1 (n);
scm_remember_upto_here_1 (n);
}
return SCM_MAKINUM (count); return SCM_MAKINUM (count);
} }
else else
@ -4217,6 +4209,8 @@ scm_init_numbers ()
abs_most_negative_fixnum = scm_i_long2big (- SCM_MOST_NEGATIVE_FIXNUM); abs_most_negative_fixnum = scm_i_long2big (- SCM_MOST_NEGATIVE_FIXNUM);
scm_permanent_object (abs_most_negative_fixnum); scm_permanent_object (abs_most_negative_fixnum);
mpz_init_set_si (z_negative_one, -1);
/* It may be possible to tune the performance of some algorithms by using /* It may be possible to tune the performance of some algorithms by using
* the following constants to avoid the creation of bignums. Please, before * the following constants to avoid the creation of bignums. Please, before
* using these values, remember the two rules of program optimization: * using these values, remember the two rules of program optimization: