14b6a78b7SSimon Schubert /* mpf_cmp_si -- Compare a float with a signed integer.
24b6a78b7SSimon Schubert
34b6a78b7SSimon Schubert Copyright 1993, 1994, 1995, 1999, 2000, 2001, 2002, 2004 Free Software
44b6a78b7SSimon Schubert Foundation, Inc.
54b6a78b7SSimon Schubert
64b6a78b7SSimon Schubert This file is part of the GNU MP Library.
74b6a78b7SSimon Schubert
84b6a78b7SSimon Schubert The GNU MP Library is free software; you can redistribute it and/or modify
94b6a78b7SSimon Schubert it under the terms of the GNU Lesser General Public License as published by
104b6a78b7SSimon Schubert the Free Software Foundation; either version 3 of the License, or (at your
114b6a78b7SSimon Schubert option) any later version.
124b6a78b7SSimon Schubert
134b6a78b7SSimon Schubert The GNU MP Library is distributed in the hope that it will be useful, but
144b6a78b7SSimon Schubert WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
154b6a78b7SSimon Schubert or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
164b6a78b7SSimon Schubert License for more details.
174b6a78b7SSimon Schubert
184b6a78b7SSimon Schubert You should have received a copy of the GNU Lesser General Public License
194b6a78b7SSimon Schubert along with the GNU MP Library. If not, see http://www.gnu.org/licenses/. */
204b6a78b7SSimon Schubert
214b6a78b7SSimon Schubert #include "gmp.h"
224b6a78b7SSimon Schubert #include "gmp-impl.h"
234b6a78b7SSimon Schubert
244b6a78b7SSimon Schubert int
mpf_cmp_si(mpf_srcptr u,long int vval)25*d2d4b659SJohn Marino mpf_cmp_si (mpf_srcptr u, long int vval) __GMP_NOTHROW
264b6a78b7SSimon Schubert {
274b6a78b7SSimon Schubert mp_srcptr up;
284b6a78b7SSimon Schubert mp_size_t usize;
294b6a78b7SSimon Schubert mp_exp_t uexp;
304b6a78b7SSimon Schubert mp_limb_t ulimb;
314b6a78b7SSimon Schubert int usign;
32*d2d4b659SJohn Marino unsigned long abs_vval;
334b6a78b7SSimon Schubert
344b6a78b7SSimon Schubert uexp = u->_mp_exp;
354b6a78b7SSimon Schubert usize = u->_mp_size;
364b6a78b7SSimon Schubert
374b6a78b7SSimon Schubert /* 1. Are the signs different? */
384b6a78b7SSimon Schubert if ((usize < 0) == (vval < 0)) /* don't use xor, type size may differ */
394b6a78b7SSimon Schubert {
404b6a78b7SSimon Schubert /* U and V are both non-negative or both negative. */
414b6a78b7SSimon Schubert if (usize == 0)
424b6a78b7SSimon Schubert /* vval >= 0 */
434b6a78b7SSimon Schubert return -(vval != 0);
444b6a78b7SSimon Schubert if (vval == 0)
454b6a78b7SSimon Schubert /* usize >= 0 */
464b6a78b7SSimon Schubert return usize != 0;
474b6a78b7SSimon Schubert /* Fall out. */
484b6a78b7SSimon Schubert }
494b6a78b7SSimon Schubert else
504b6a78b7SSimon Schubert {
514b6a78b7SSimon Schubert /* Either U or V is negative, but not both. */
524b6a78b7SSimon Schubert return usize >= 0 ? 1 : -1;
534b6a78b7SSimon Schubert }
544b6a78b7SSimon Schubert
554b6a78b7SSimon Schubert /* U and V have the same sign and are both non-zero. */
564b6a78b7SSimon Schubert
574b6a78b7SSimon Schubert usign = usize >= 0 ? 1 : -1;
584b6a78b7SSimon Schubert usize = ABS (usize);
59*d2d4b659SJohn Marino abs_vval = ABS_CAST (unsigned long, vval);
604b6a78b7SSimon Schubert
614b6a78b7SSimon Schubert /* 2. Are the exponents different (V's exponent == 1)? */
624b6a78b7SSimon Schubert #if GMP_NAIL_BITS != 0
63*d2d4b659SJohn Marino if (uexp > 1 + (abs_vval > GMP_NUMB_MAX))
644b6a78b7SSimon Schubert return usign;
65*d2d4b659SJohn Marino if (uexp < 1 + (abs_vval > GMP_NUMB_MAX))
664b6a78b7SSimon Schubert return -usign;
674b6a78b7SSimon Schubert #else
684b6a78b7SSimon Schubert if (uexp > 1)
694b6a78b7SSimon Schubert return usign;
704b6a78b7SSimon Schubert if (uexp < 1)
714b6a78b7SSimon Schubert return -usign;
724b6a78b7SSimon Schubert #endif
734b6a78b7SSimon Schubert
744b6a78b7SSimon Schubert up = u->_mp_d;
754b6a78b7SSimon Schubert
764b6a78b7SSimon Schubert ulimb = up[usize - 1];
774b6a78b7SSimon Schubert #if GMP_NAIL_BITS != 0
784b6a78b7SSimon Schubert if (usize >= 2 && uexp == 2)
794b6a78b7SSimon Schubert {
804b6a78b7SSimon Schubert if ((ulimb >> GMP_NAIL_BITS) != 0)
814b6a78b7SSimon Schubert return usign;
824b6a78b7SSimon Schubert ulimb = (ulimb << GMP_NUMB_BITS) | up[usize - 2];
834b6a78b7SSimon Schubert usize--;
844b6a78b7SSimon Schubert }
854b6a78b7SSimon Schubert #endif
864b6a78b7SSimon Schubert usize--;
874b6a78b7SSimon Schubert
884b6a78b7SSimon Schubert /* 3. Compare the most significant mantissa limb with V. */
89*d2d4b659SJohn Marino if (ulimb > abs_vval)
904b6a78b7SSimon Schubert return usign;
91*d2d4b659SJohn Marino else if (ulimb < abs_vval)
924b6a78b7SSimon Schubert return -usign;
934b6a78b7SSimon Schubert
944b6a78b7SSimon Schubert /* Ignore zeroes at the low end of U. */
954b6a78b7SSimon Schubert while (*up == 0)
964b6a78b7SSimon Schubert {
974b6a78b7SSimon Schubert up++;
984b6a78b7SSimon Schubert usize--;
994b6a78b7SSimon Schubert }
1004b6a78b7SSimon Schubert
1014b6a78b7SSimon Schubert /* 4. Now, if the number of limbs are different, we have a difference
1024b6a78b7SSimon Schubert since we have made sure the trailing limbs are not zero. */
1034b6a78b7SSimon Schubert if (usize > 0)
1044b6a78b7SSimon Schubert return usign;
1054b6a78b7SSimon Schubert
1064b6a78b7SSimon Schubert /* Wow, we got zero even if we tried hard to avoid it. */
1074b6a78b7SSimon Schubert return 0;
1084b6a78b7SSimon Schubert }
109