diff options
Diffstat (limited to 'libguile/integers.c')
-rw-r--r-- | libguile/integers.c | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/libguile/integers.c b/libguile/integers.c index ff5499af9..fc71c7acc 100644 --- a/libguile/integers.c +++ b/libguile/integers.c @@ -2008,3 +2008,23 @@ scm_integer_logtest_zz (SCM x, SCM y) { return scm_is_eq (scm_integer_logand_zz (x, y), SCM_INUM0); } + +int +scm_integer_logbit_ui (unsigned long index, scm_t_inum n) +{ + if (index < SCM_LONG_BIT) + /* Assume two's complement representation. */ + return (n >> index) & 1; + else + return n < 0; +} + +int +scm_integer_logbit_uz (unsigned long index, SCM n) +{ + mpz_t zn; + alias_bignum_to_mpz (scm_bignum (n), zn); + int val = mpz_tstbit (zn, index); + scm_remember_upto_here_1 (n); + return val; +} |