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(scm_lognot): Rewrite using ~ and mpz_com, for directness

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and to have non-integer types rejected as per other logical funcs.
This commit is contained in:
Kevin Ryde 2003-08-30 00:04:42 +00:00
parent 813729f6fa
commit f9811f9f2e
1 changed files with 16 additions and 1 deletions
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17
libguile/numbers.c
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@ -1247,7 +1247,22 @@ SCM_DEFINE (scm_lognot, "lognot", 1, 0, 0,
"@end lisp")
#define FUNC_NAME s_scm_lognot
{
return scm_difference (SCM_MAKINUM (-1L), n);
if (SCM_INUMP (n)) {
/* No overflow here, just need to toggle all the bits making up the inum.
Enhancement: No need to strip the tag and add it back, could just xor
a block of 1 bits, if that worked with the various debug versions of
the SCM typedef. */
return SCM_MAKINUM (~ SCM_INUM (n));
} else if (SCM_BIGP (n)) {
SCM result = scm_i_mkbig ();
mpz_com (SCM_I_BIG_MPZ (result), SCM_I_BIG_MPZ (n));
scm_remember_upto_here_1 (n);
return result;
} else {
SCM_WRONG_TYPE_ARG (SCM_ARG1, n);
}
}
#undef FUNC_NAME