1/* mpf_cmp -- Compare two floats.
2
3Copyright 1993, 1994, 1996, 2001, 2015 Free Software Foundation, Inc.
4
5This file is part of the GNU MP Library.
6
7The GNU MP Library is free software; you can redistribute it and/or modify
8it under the terms of either:
9
10  * the GNU Lesser General Public License as published by the Free
11    Software Foundation; either version 3 of the License, or (at your
12    option) any later version.
13
14or
15
16  * the GNU General Public License as published by the Free Software
17    Foundation; either version 2 of the License, or (at your option) any
18    later version.
19
20or both in parallel, as here.
21
22The GNU MP Library is distributed in the hope that it will be useful, but
23WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
24or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
25for more details.
26
27You should have received copies of the GNU General Public License and the
28GNU Lesser General Public License along with the GNU MP Library.  If not,
29see https://www.gnu.org/licenses/.  */
30
31#include "gmp-impl.h"
32
33int
34mpf_cmp (mpf_srcptr u, mpf_srcptr v) __GMP_NOTHROW
35{
36  mp_srcptr up, vp;
37  mp_size_t usize, vsize;
38  mp_exp_t uexp, vexp;
39  int cmp;
40  int usign;
41
42  usize = SIZ(u);
43  vsize = SIZ(v);
44  usign = usize >= 0 ? 1 : -1;
45
46  /* 1. Are the signs different?  */
47  if ((usize ^ vsize) >= 0)
48    {
49      /* U and V are both non-negative or both negative.  */
50      if (usize == 0)
51	/* vsize >= 0 */
52	return -(vsize != 0);
53      if (vsize == 0)
54	/* usize >= 0 */
55	return usize != 0;
56      /* Fall out.  */
57    }
58  else
59    {
60      /* Either U or V is negative, but not both.  */
61      return usign;
62    }
63
64  /* U and V have the same sign and are both non-zero.  */
65
66  uexp = EXP(u);
67  vexp = EXP(v);
68
69  /* 2. Are the exponents different?  */
70  if (uexp > vexp)
71    return usign;
72  if (uexp < vexp)
73    return -usign;
74
75  usize = ABS (usize);
76  vsize = ABS (vsize);
77
78  up = PTR (u);
79  vp = PTR (v);
80
81#define STRICT_MPF_NORMALIZATION 0
82#if ! STRICT_MPF_NORMALIZATION
83  /* Ignore zeroes at the low end of U and V.  */
84  do {
85    mp_limb_t tl;
86    tl = up[0];
87    MPN_STRIP_LOW_ZEROS_NOT_ZERO (up, usize, tl);
88    tl = vp[0];
89    MPN_STRIP_LOW_ZEROS_NOT_ZERO (vp, vsize, tl);
90  } while (0);
91#endif
92
93  if (usize > vsize)
94    {
95      cmp = mpn_cmp (up + usize - vsize, vp, vsize);
96      /* if (cmp == 0) */
97      /*	return usign; */
98      ++cmp;
99    }
100  else if (vsize > usize)
101    {
102      cmp = mpn_cmp (up, vp + vsize - usize, usize);
103      /* if (cmp == 0) */
104      /*	return -usign; */
105    }
106  else
107    {
108      cmp = mpn_cmp (up, vp, usize);
109      if (cmp == 0)
110	return 0;
111    }
112  return cmp > 0 ? usign : -usign;
113}
114