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., 675 Mass Ave, Cambridge, MA 02139, USA.
20 */
21/*
22 * BEGIN_DESC
23 *
24 *  File:
25 *	@(#)	pa/spmath/sfcmp.c		$Revision: 1.1.1.1 $
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 */
48int
49sgl_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    }
156