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/dfcmp.c		$Revision: 1.1 $
26 *
27 *  Purpose:
28 *	dbl_cmp: compare two values
29 *
30 *  External Interfaces:
31 *	dbl_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
43#include "float.h"
44#include "dbl_float.h"
45
46/*
47 * dbl_cmp: compare two values
48 */
49int
50dbl_fcmp (dbl_floating_point * leftptr, dbl_floating_point * rightptr,
51	  unsigned int cond, unsigned int *status)
52
53                       /* The predicate to be tested */
54
55    {
56    register unsigned int leftp1, leftp2, rightp1, rightp2;
57    register int xorresult;
58
59    /* Create local copies of the numbers */
60    Dbl_copyfromptr(leftptr,leftp1,leftp2);
61    Dbl_copyfromptr(rightptr,rightp1,rightp2);
62    /*
63     * Test for NaN
64     */
65    if(    (Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
66        || (Dbl_exponent(rightp1) == DBL_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( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
72	    && Dbl_isnotzero_mantissa(leftp1,leftp2)
73	    && (Exception(cond) || Dbl_isone_signaling(leftp1)))
74	   ||
75	    ((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT)
76	    && Dbl_isnotzero_mantissa(rightp1,rightp2)
77	    && (Exception(cond) || Dbl_isone_signaling(rightp1))) )
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( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
90	    && Dbl_isnotzero_mantissa(leftp1,leftp2))
91	   ||
92	    ((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT)
93	    && Dbl_isnotzero_mantissa(rightp1,rightp2)) )
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    Dbl_xortointp1(leftp1,rightp1,xorresult);
104    if( xorresult < 0 )
105        {
106        /* left negative => less, left positive => greater.
107         * equal is possible if both operands are zeros. */
108        if( Dbl_iszero_exponentmantissa(leftp1,leftp2)
109	  && Dbl_iszero_exponentmantissa(rightp1,rightp2) )
110            {
111	    Set_status_cbit(Equal(cond));
112	    }
113	else if( Dbl_isone_sign(leftp1) )
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(Dbl_isequal(leftp1,leftp2,rightp1,rightp2))
125        {
126        Set_status_cbit(Equal(cond));
127        }
128    else if( Dbl_iszero_sign(leftp1) )
129        {
130        /* Positive compare */
131	if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) )
132	    {
133	    Set_status_cbit(Lessthan(cond));
134	    }
135	else if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) )
136	    {
137	    Set_status_cbit(Greaterthan(cond));
138	    }
139	else
140	    {
141	    /* Equal first parts.  Now we must use unsigned compares to
142	     * resolve the two possibilities. */
143	    if( Dbl_allp2(leftp2) < Dbl_allp2(rightp2) )
144		{
145		Set_status_cbit(Lessthan(cond));
146		}
147	    else
148		{
149		Set_status_cbit(Greaterthan(cond));
150		}
151	    }
152	}
153    else
154        {
155        /* Negative compare.  Signed or unsigned compares
156         * both work the same.  That distinction is only
157         * important when the sign bits differ. */
158	if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) )
159	    {
160	    Set_status_cbit(Lessthan(cond));
161	    }
162	else if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) )
163	    {
164	    Set_status_cbit(Greaterthan(cond));
165	    }
166	else
167	    {
168	    /* Equal first parts.  Now we must use unsigned compares to
169	     * resolve the two possibilities. */
170	    if( Dbl_allp2(leftp2) > Dbl_allp2(rightp2) )
171		{
172		Set_status_cbit(Lessthan(cond));
173		}
174	    else
175		{
176		Set_status_cbit(Greaterthan(cond));
177		}
178	    }
179        }
180	return(NOEXCEPTION);
181    }
182