1 /* $NetBSD: dfcmp.c,v 1.4 2012/02/04 17:03:09 skrll Exp $ */
2
3 /* $OpenBSD: dfcmp.c,v 1.4 2001/03/29 03:58:17 mickey Exp $ */
4
5 /*
6 * Copyright 1996 1995 by Open Software Foundation, Inc.
7 * All Rights Reserved
8 *
9 * Permission to use, copy, modify, and distribute this software and
10 * its documentation for any purpose and without fee is hereby granted,
11 * provided that the above copyright notice appears in all copies and
12 * that both the copyright notice and this permission notice appear in
13 * supporting documentation.
14 *
15 * OSF DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
16 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
17 * FOR A PARTICULAR PURPOSE.
18 *
19 * IN NO EVENT SHALL OSF BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
20 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
21 * LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
22 * NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
23 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
24 */
25 /*
26 * pmk1.1
27 */
28 /*
29 * (c) Copyright 1986 HEWLETT-PACKARD COMPANY
30 *
31 * To anyone who acknowledges that this file is provided "AS IS"
32 * without any express or implied warranty:
33 * permission to use, copy, modify, and distribute this file
34 * for any purpose is hereby granted without fee, provided that
35 * the above copyright notice and this notice appears in all
36 * copies, and that the name of Hewlett-Packard Company not be
37 * used in advertising or publicity pertaining to distribution
38 * of the software without specific, written prior permission.
39 * Hewlett-Packard Company makes no representations about the
40 * suitability of this software for any purpose.
41 */
42
43
44 #include <sys/cdefs.h>
45 __KERNEL_RCSID(0, "$NetBSD: dfcmp.c,v 1.4 2012/02/04 17:03:09 skrll Exp $");
46
47 #include "../spmath/float.h"
48 #include "../spmath/dbl_float.h"
49
50 /*
51 * dbl_cmp: compare two values
52 */
53 int
dbl_fcmp(dbl_floating_point * leftptr,dbl_floating_point * rightptr,unsigned int cond,unsigned int * status)54 dbl_fcmp(dbl_floating_point *leftptr, dbl_floating_point *rightptr,
55 unsigned int cond, unsigned int *status)
56 {
57 register unsigned int leftp1, leftp2, rightp1, rightp2;
58 register int xorresult;
59
60 /* Create local copies of the numbers */
61 Dbl_copyfromptr(leftptr,leftp1,leftp2);
62 Dbl_copyfromptr(rightptr,rightp1,rightp2);
63 /*
64 * Test for NaN
65 */
66 if( (Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
67 || (Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT) )
68 {
69 /* Check if a NaN is involved. Signal an invalid exception when
70 * comparing a signaling NaN or when comparing quiet NaNs and the
71 * low bit of the condition is set */
72 if( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
73 && Dbl_isnotzero_mantissa(leftp1,leftp2)
74 && (Exception(cond) || Dbl_isone_signaling(leftp1)))
75 ||
76 ((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT)
77 && Dbl_isnotzero_mantissa(rightp1,rightp2)
78 && (Exception(cond) || Dbl_isone_signaling(rightp1))) )
79 {
80 if( Is_invalidtrap_enabled() ) {
81 Set_status_cbit(Unordered(cond));
82 return(INVALIDEXCEPTION);
83 }
84 else Set_invalidflag();
85 Set_status_cbit(Unordered(cond));
86 return(NOEXCEPTION);
87 }
88 /* All the exceptional conditions are handled, now special case
89 NaN compares */
90 else if( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
91 && Dbl_isnotzero_mantissa(leftp1,leftp2))
92 ||
93 ((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT)
94 && Dbl_isnotzero_mantissa(rightp1,rightp2)) )
95 {
96 /* NaNs always compare unordered. */
97 Set_status_cbit(Unordered(cond));
98 return(NOEXCEPTION);
99 }
100 /* infinities will drop down to the normal compare mechanisms */
101 }
102 /* First compare for unequal signs => less or greater or
103 * special equal case */
104 Dbl_xortointp1(leftp1,rightp1,xorresult);
105 if( xorresult < 0 )
106 {
107 /* left negative => less, left positive => greater.
108 * equal is possible if both operands are zeros. */
109 if( Dbl_iszero_exponentmantissa(leftp1,leftp2)
110 && Dbl_iszero_exponentmantissa(rightp1,rightp2) )
111 {
112 Set_status_cbit(Equal(cond));
113 }
114 else if( Dbl_isone_sign(leftp1) )
115 {
116 Set_status_cbit(Lessthan(cond));
117 }
118 else
119 {
120 Set_status_cbit(Greaterthan(cond));
121 }
122 }
123 /* Signs are the same. Treat negative numbers separately
124 * from the positives because of the reversed sense. */
125 else if(Dbl_isequal(leftp1,leftp2,rightp1,rightp2))
126 {
127 Set_status_cbit(Equal(cond));
128 }
129 else if( Dbl_iszero_sign(leftp1) )
130 {
131 /* Positive compare */
132 if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) )
133 {
134 Set_status_cbit(Lessthan(cond));
135 }
136 else if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) )
137 {
138 Set_status_cbit(Greaterthan(cond));
139 }
140 else
141 {
142 /* Equal first parts. Now we must use unsigned compares to
143 * resolve the two possibilities. */
144 if( Dbl_allp2(leftp2) < Dbl_allp2(rightp2) )
145 {
146 Set_status_cbit(Lessthan(cond));
147 }
148 else
149 {
150 Set_status_cbit(Greaterthan(cond));
151 }
152 }
153 }
154 else
155 {
156 /* Negative compare. Signed or unsigned compares
157 * both work the same. That distinction is only
158 * important when the sign bits differ. */
159 if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) )
160 {
161 Set_status_cbit(Lessthan(cond));
162 }
163 else if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) )
164 {
165 Set_status_cbit(Greaterthan(cond));
166 }
167 else
168 {
169 /* Equal first parts. Now we must use unsigned compares to
170 * resolve the two possibilities. */
171 if( Dbl_allp2(leftp2) > Dbl_allp2(rightp2) )
172 {
173 Set_status_cbit(Lessthan(cond));
174 }
175 else
176 {
177 Set_status_cbit(Greaterthan(cond));
178 }
179 }
180 }
181 return(NOEXCEPTION);
182 }
183