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1da177e4 LT |
1 | /* |
2 | * Linux/PA-RISC Project (http://www.parisc-linux.org/) | |
3 | * | |
4 | * Floating-point emulation code | |
5 | * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License as published by | |
9 | * the Free Software Foundation; either version 2, or (at your option) | |
10 | * any later version. | |
11 | * | |
12 | * This program is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | * GNU General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU General Public License | |
18 | * along with this program; if not, write to the Free Software | |
19 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
20 | */ | |
21 | /* | |
22 | * BEGIN_DESC | |
23 | * | |
24 | * File: | |
25 | * @(#) pa/spmath/sfcmp.c $Revision: 1.1 $ | |
26 | * | |
27 | * Purpose: | |
28 | * sgl_cmp: compare two values | |
29 | * | |
30 | * External Interfaces: | |
31 | * sgl_fcmp(leftptr, rightptr, cond, status) | |
32 | * | |
33 | * Internal Interfaces: | |
34 | * | |
35 | * Theory: | |
36 | * <<please update with a overview of the operation of this file>> | |
37 | * | |
38 | * END_DESC | |
39 | */ | |
40 | ||
41 | ||
42 | #include "float.h" | |
43 | #include "sgl_float.h" | |
44 | ||
45 | /* | |
46 | * sgl_cmp: compare two values | |
47 | */ | |
48 | int | |
49 | sgl_fcmp (sgl_floating_point * leftptr, sgl_floating_point * rightptr, | |
50 | unsigned int cond, unsigned int *status) | |
51 | ||
52 | /* The predicate to be tested */ | |
53 | ||
54 | { | |
55 | register unsigned int left, right; | |
56 | register int xorresult; | |
57 | ||
58 | /* Create local copies of the numbers */ | |
59 | left = *leftptr; | |
60 | right = *rightptr; | |
61 | ||
62 | /* | |
63 | * Test for NaN | |
64 | */ | |
65 | if( (Sgl_exponent(left) == SGL_INFINITY_EXPONENT) | |
66 | || (Sgl_exponent(right) == SGL_INFINITY_EXPONENT) ) | |
67 | { | |
68 | /* Check if a NaN is involved. Signal an invalid exception when | |
69 | * comparing a signaling NaN or when comparing quiet NaNs and the | |
70 | * low bit of the condition is set */ | |
71 | if( ( (Sgl_exponent(left) == SGL_INFINITY_EXPONENT) | |
72 | && Sgl_isnotzero_mantissa(left) | |
73 | && (Exception(cond) || Sgl_isone_signaling(left))) | |
74 | || | |
75 | ( (Sgl_exponent(right) == SGL_INFINITY_EXPONENT) | |
76 | && Sgl_isnotzero_mantissa(right) | |
77 | && (Exception(cond) || Sgl_isone_signaling(right)) ) ) | |
78 | { | |
79 | if( Is_invalidtrap_enabled() ) { | |
80 | Set_status_cbit(Unordered(cond)); | |
81 | return(INVALIDEXCEPTION); | |
82 | } | |
83 | else Set_invalidflag(); | |
84 | Set_status_cbit(Unordered(cond)); | |
85 | return(NOEXCEPTION); | |
86 | } | |
87 | /* All the exceptional conditions are handled, now special case | |
88 | NaN compares */ | |
89 | else if( ((Sgl_exponent(left) == SGL_INFINITY_EXPONENT) | |
90 | && Sgl_isnotzero_mantissa(left)) | |
91 | || | |
92 | ((Sgl_exponent(right) == SGL_INFINITY_EXPONENT) | |
93 | && Sgl_isnotzero_mantissa(right)) ) | |
94 | { | |
95 | /* NaNs always compare unordered. */ | |
96 | Set_status_cbit(Unordered(cond)); | |
97 | return(NOEXCEPTION); | |
98 | } | |
99 | /* infinities will drop down to the normal compare mechanisms */ | |
100 | } | |
101 | /* First compare for unequal signs => less or greater or | |
102 | * special equal case */ | |
103 | Sgl_xortointp1(left,right,xorresult); | |
104 | if( xorresult < 0 ) | |
105 | { | |
106 | /* left negative => less, left positive => greater. | |
107 | * equal is possible if both operands are zeros. */ | |
108 | if( Sgl_iszero_exponentmantissa(left) | |
109 | && Sgl_iszero_exponentmantissa(right) ) | |
110 | { | |
111 | Set_status_cbit(Equal(cond)); | |
112 | } | |
113 | else if( Sgl_isone_sign(left) ) | |
114 | { | |
115 | Set_status_cbit(Lessthan(cond)); | |
116 | } | |
117 | else | |
118 | { | |
119 | Set_status_cbit(Greaterthan(cond)); | |
120 | } | |
121 | } | |
122 | /* Signs are the same. Treat negative numbers separately | |
123 | * from the positives because of the reversed sense. */ | |
124 | else if( Sgl_all(left) == Sgl_all(right) ) | |
125 | { | |
126 | Set_status_cbit(Equal(cond)); | |
127 | } | |
128 | else if( Sgl_iszero_sign(left) ) | |
129 | { | |
130 | /* Positive compare */ | |
131 | if( Sgl_all(left) < Sgl_all(right) ) | |
132 | { | |
133 | Set_status_cbit(Lessthan(cond)); | |
134 | } | |
135 | else | |
136 | { | |
137 | Set_status_cbit(Greaterthan(cond)); | |
138 | } | |
139 | } | |
140 | else | |
141 | { | |
142 | /* Negative compare. Signed or unsigned compares | |
143 | * both work the same. That distinction is only | |
144 | * important when the sign bits differ. */ | |
145 | if( Sgl_all(left) > Sgl_all(right) ) | |
146 | { | |
147 | Set_status_cbit(Lessthan(cond)); | |
148 | } | |
149 | else | |
150 | { | |
151 | Set_status_cbit(Greaterthan(cond)); | |
152 | } | |
153 | } | |
154 | return(NOEXCEPTION); | |
155 | } |