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Make logcount handle bignums

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* src/data.c (Flogcount): Handle bignums.
* test/src/data-tests.el (data-tests-logcount): New test.
This commit is contained in:
Tom Tromey 2018-07-07 14:22:44 -06:00
parent c7e393bc41
commit a770fb4428
2 changed files with 19 additions and 1 deletions
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17
src/data.c
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@ -3184,7 +3184,22 @@ of VALUE. If VALUE is negative, return the number of zero bits in the
representation. */)
(Lisp_Object value)
{
CHECK_FIXNUM (value);
CHECK_INTEGER (value);
if (BIGNUMP (value))
{
if (mpz_cmp_si (XBIGNUM (value)->value, 0) >= 0)
return make_fixnum (mpz_popcount (XBIGNUM (value)->value));
mpz_t tem;
mpz_init (tem);
mpz_neg (tem, XBIGNUM (value)->value);
mpz_sub_ui (tem, tem, 1);
Lisp_Object result = make_fixnum (mpz_popcount (tem));
mpz_clear (tem);
return result;
}
eassume (FIXNUMP (value));
EMACS_INT v = XINT (value) < 0 ? -1 - XINT (value) : XINT (value);
return make_fixnum (EMACS_UINT_WIDTH <= UINT_WIDTH
? count_one_bits (v)

3
test/src/data-tests.el
View file

@ -587,4 +587,7 @@ comparing the subr with a much slower lisp implementation."
(should (< (1- most-negative-fixnum) most-negative-fixnum))
(should (fixnump (1- (1+ most-positive-fixnum)))))
(ert-deftest data-tests-logcount ()
(should (= (logcount (read "#xffffffffffffffffffffffffffffffff")) 128)))
;;; data-tests.el ends here