1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Linux/PA-RISC Project (http://www.parisc-linux.org/)
4 *
5 * Floating-point emulation code
6 * Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
7 */
8 /*
9 * BEGIN_DESC
10 *
11 * File:
12 * @(#) pa/spmath/sfcmp.c $Revision: 1.1 $
13 *
14 * Purpose:
15 * sgl_cmp: compare two values
16 *
17 * External Interfaces:
18 * sgl_fcmp(leftptr, rightptr, cond, status)
19 *
20 * Internal Interfaces:
21 *
22 * Theory:
23 * <<please update with a overview of the operation of this file>>
24 *
25 * END_DESC
26 */
27
28
29 #include "float.h"
30 #include "sgl_float.h"
31
32 /*
33 * sgl_cmp: compare two values
34 */
35 int
36 sgl_fcmp (sgl_floating_point * leftptr, sgl_floating_point * rightptr,
37 unsigned int cond, unsigned int *status)
38
39 /* The predicate to be tested */
40
41 {
42 register unsigned int left, right;
43 register int xorresult;
44
45 /* Create local copies of the numbers */
46 left = *leftptr;
47 right = *rightptr;
48
49 /*
50 * Test for NaN
51 */
52 if( (Sgl_exponent(left) == SGL_INFINITY_EXPONENT)
53 || (Sgl_exponent(right) == SGL_INFINITY_EXPONENT) )
54 {
55 /* Check if a NaN is involved. Signal an invalid exception when
56 * comparing a signaling NaN or when comparing quiet NaNs and the
57 * low bit of the condition is set */
58 if( ( (Sgl_exponent(left) == SGL_INFINITY_EXPONENT)
59 && Sgl_isnotzero_mantissa(left)
60 && (Exception(cond) || Sgl_isone_signaling(left)))
61 ||
62 ( (Sgl_exponent(right) == SGL_INFINITY_EXPONENT)
63 && Sgl_isnotzero_mantissa(right)
64 && (Exception(cond) || Sgl_isone_signaling(right)) ) )
65 {
66 if( Is_invalidtrap_enabled() ) {
67 Set_status_cbit(Unordered(cond));
68 return(INVALIDEXCEPTION);
69 }
70 else Set_invalidflag();
71 Set_status_cbit(Unordered(cond));
72 return(NOEXCEPTION);
73 }
74 /* All the exceptional conditions are handled, now special case
75 NaN compares */
76 else if( ((Sgl_exponent(left) == SGL_INFINITY_EXPONENT)
77 && Sgl_isnotzero_mantissa(left))
78 ||
79 ((Sgl_exponent(right) == SGL_INFINITY_EXPONENT)
80 && Sgl_isnotzero_mantissa(right)) )
81 {
82 /* NaNs always compare unordered. */
83 Set_status_cbit(Unordered(cond));
84 return(NOEXCEPTION);
85 }
86 /* infinities will drop down to the normal compare mechanisms */
87 }
88 /* First compare for unequal signs => less or greater or
89 * special equal case */
90 Sgl_xortointp1(left,right,xorresult);
91 if( xorresult < 0 )
92 {
93 /* left negative => less, left positive => greater.
94 * equal is possible if both operands are zeros. */
95 if( Sgl_iszero_exponentmantissa(left)
96 && Sgl_iszero_exponentmantissa(right) )
97 {
98 Set_status_cbit(Equal(cond));
99 }
100 else if( Sgl_isone_sign(left) )
101 {
102 Set_status_cbit(Lessthan(cond));
103 }
104 else
105 {
106 Set_status_cbit(Greaterthan(cond));
107 }
108 }
109 /* Signs are the same. Treat negative numbers separately
110 * from the positives because of the reversed sense. */
111 else if( Sgl_all(left) == Sgl_all(right) )
112 {
113 Set_status_cbit(Equal(cond));
114 }
115 else if( Sgl_iszero_sign(left) )
116 {
117 /* Positive compare */
118 if( Sgl_all(left) < Sgl_all(right) )
119 {
120 Set_status_cbit(Lessthan(cond));
121 }
122 else
123 {
124 Set_status_cbit(Greaterthan(cond));
125 }
126 }
127 else
128 {
129 /* Negative compare. Signed or unsigned compares
130 * both work the same. That distinction is only
131 * important when the sign bits differ. */
132 if( Sgl_all(left) > Sgl_all(right) )
133 {
134 Set_status_cbit(Lessthan(cond));
135 }
136 else
137 {
138 Set_status_cbit(Greaterthan(cond));
139 }
140 }
141 return(NOEXCEPTION);
142 }