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Optimize logand against a positive inum

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* libguile/integers.c (scm_integer_logand_zi): Optimize.
This commit is contained in:
Andy Wingo 2022-01-10 11:56:13 +01:00
parent 6fe43301aa
commit 9e5aa173c7
1 changed files with 12 additions and 0 deletions
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12
libguile/integers.c
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@ -2119,6 +2119,18 @@ scm_integer_logand_zi (struct scm_bignum *x, scm_t_inum y)
if (y == 0) if (y == 0)
return SCM_INUM0; return SCM_INUM0;
if (y > 0)
{
mp_limb_t rd = bignum_limbs (x)[0];
mp_limb_t yd = y;
if (bignum_is_negative (x))
rd = ~rd + 1;
scm_remember_upto_here_1 (x);
rd &= yd;
// Result must be a positive inum.
return SCM_I_MAKINUM (rd);
}
mpz_t result, zx, zy; mpz_t result, zx, zy;
mpz_init (result); mpz_init (result);
alias_bignum_to_mpz (x, zx); alias_bignum_to_mpz (x, zx);