/*
* Linux/PA-RISC Project (http://www.parisc-linux.org/)
*
* Floating-point emulation code
* Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
/*
* BEGIN_DESC
*
* File:
* @(#) pa/spmath/dfcmp.c $Revision: 1.1 $
*
* Purpose:
* dbl_cmp: compare two values
*
* External Interfaces:
* dbl_fcmp(leftptr, rightptr, cond, status)
*
* Internal Interfaces:
*
* Theory:
* <<please update with a overview of the operation of this file>>
*
* END_DESC
*/
#include "float.h"
#include "dbl_float.h"
/*
* dbl_cmp: compare two values
*/
int
dbl_fcmp (dbl_floating_point * leftptr, dbl_floating_point * rightptr,
unsigned int cond, unsigned int *status)
/* The predicate to be tested */
{
register unsigned int leftp1, leftp2, rightp1, rightp2;
register int xorresult;
/* Create local copies of the numbers */
Dbl_copyfromptr(leftptr,leftp1,leftp2);
Dbl_copyfromptr(rightptr,rightp1,rightp2);
/*
* Test for NaN
*/
if( (Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
|| (Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT) )
{
/* Check if a NaN is involved. Signal an invalid exception when
* comparing a signaling NaN or when comparing quiet NaNs and the
* low bit of the condition is set */
if( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
&& Dbl_isnotzero_mantissa(leftp1,leftp2)
&& (Exception(cond) || Dbl_isone_signaling(leftp1)))
||
((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT)
&& Dbl_isnotzero_mantissa(rightp1,rightp2)
&& (Exception(cond) || Dbl_isone_signaling(rightp1))) )
{
if( Is_invalidtrap_enabled() ) {
Set_status_cbit(Unordered(cond));
return(INVALIDEXCEPTION);
}
else Set_invalidflag();
Set_status_cbit(Unordered(cond));
return(NOEXCEPTION);
}
/* All the exceptional conditions are handled, now special case
NaN compares */
else if( ((Dbl_exponent(leftp1) == DBL_INFINITY_EXPONENT)
&& Dbl_isnotzero_mantissa(leftp1,leftp2))
||
((Dbl_exponent(rightp1) == DBL_INFINITY_EXPONENT)
&& Dbl_isnotzero_mantissa(rightp1,rightp2)) )
{
/* NaNs always compare unordered. */
Set_status_cbit(Unordered(cond));
return(NOEXCEPTION);
}
/* infinities will drop down to the normal compare mechanisms */
}
/* First compare for unequal signs => less or greater or
* special equal case */
Dbl_xortointp1(leftp1,rightp1,xorresult);
if( xorresult < 0 )
{
/* left negative => less, left positive => greater.
* equal is possible if both operands are zeros. */
if( Dbl_iszero_exponentmantissa(leftp1,leftp2)
&& Dbl_iszero_exponentmantissa(rightp1,rightp2) )
{
Set_status_cbit(Equal(cond));
}
else if( Dbl_isone_sign(leftp1) )
{
Set_status_cbit(Lessthan(cond));
}
else
{
Set_status_cbit(Greaterthan(cond));
}
}
/* Signs are the same. Treat negative numbers separately
* from the positives because of the reversed sense. */
else if(Dbl_isequal(leftp1,leftp2,rightp1,rightp2))
{
Set_status_cbit(Equal(cond));
}
else if( Dbl_iszero_sign(leftp1) )
{
/* Positive compare */
if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) )
{
Set_status_cbit(Lessthan(cond));
}
else if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) )
{
Set_status_cbit(Greaterthan(cond));
}
else
{
/* Equal first parts. Now we must use unsigned compares to
* resolve the two possibilities. */
if( Dbl_allp2(leftp2) < Dbl_allp2(rightp2) )
{
Set_status_cbit(Lessthan(cond));
}
else
{
Set_status_cbit(Greaterthan(cond));
}
}
}
else
{
/* Negative compare. Signed or unsigned compares
* both work the same. That distinction is only
* important when the sign bits differ. */
if( Dbl_allp1(leftp1) > Dbl_allp1(rightp1) )
{
Set_status_cbit(Lessthan(cond));
}
else if( Dbl_allp1(leftp1) < Dbl_allp1(rightp1) )
{
Set_status_cbit(Greaterthan(cond));
}
else
{
/* Equal first parts. Now we must use unsigned compares to
* resolve the two possibilities. */
if( Dbl_allp2(leftp2) > Dbl_allp2(rightp2) )
{
Set_status_cbit(Lessthan(cond));
}
else
{
Set_status_cbit(Greaterthan(cond));
}
}
}
return(NOEXCEPTION);
}
