156 lines
4.4 KiB
C
156 lines
4.4 KiB
C
/*
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* Linux/PA-RISC Project (http://www.parisc-linux.org/)
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*
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* Floating-point emulation code
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* Copyright (C) 2001 Hewlett-Packard (Paul Bame) <bame@debian.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*/
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/*
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* BEGIN_DESC
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*
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* File:
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* @(#) pa/spmath/sfcmp.c $Revision: 1.1 $
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*
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* Purpose:
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* sgl_cmp: compare two values
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*
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* External Interfaces:
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* sgl_fcmp(leftptr, rightptr, cond, status)
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*
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* Internal Interfaces:
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*
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* Theory:
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* <<please update with a overview of the operation of this file>>
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*
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* END_DESC
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*/
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#include "float.h"
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#include "sgl_float.h"
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/*
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* sgl_cmp: compare two values
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*/
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int
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sgl_fcmp (sgl_floating_point * leftptr, sgl_floating_point * rightptr,
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unsigned int cond, unsigned int *status)
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/* The predicate to be tested */
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{
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register unsigned int left, right;
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register int xorresult;
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/* Create local copies of the numbers */
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left = *leftptr;
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right = *rightptr;
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/*
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* Test for NaN
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*/
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if( (Sgl_exponent(left) == SGL_INFINITY_EXPONENT)
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|| (Sgl_exponent(right) == SGL_INFINITY_EXPONENT) )
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{
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/* Check if a NaN is involved. Signal an invalid exception when
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* comparing a signaling NaN or when comparing quiet NaNs and the
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* low bit of the condition is set */
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if( ( (Sgl_exponent(left) == SGL_INFINITY_EXPONENT)
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&& Sgl_isnotzero_mantissa(left)
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&& (Exception(cond) || Sgl_isone_signaling(left)))
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||
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( (Sgl_exponent(right) == SGL_INFINITY_EXPONENT)
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&& Sgl_isnotzero_mantissa(right)
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&& (Exception(cond) || Sgl_isone_signaling(right)) ) )
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{
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if( Is_invalidtrap_enabled() ) {
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Set_status_cbit(Unordered(cond));
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return(INVALIDEXCEPTION);
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}
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else Set_invalidflag();
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Set_status_cbit(Unordered(cond));
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return(NOEXCEPTION);
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}
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/* All the exceptional conditions are handled, now special case
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NaN compares */
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else if( ((Sgl_exponent(left) == SGL_INFINITY_EXPONENT)
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&& Sgl_isnotzero_mantissa(left))
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||
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((Sgl_exponent(right) == SGL_INFINITY_EXPONENT)
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&& Sgl_isnotzero_mantissa(right)) )
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{
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/* NaNs always compare unordered. */
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Set_status_cbit(Unordered(cond));
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return(NOEXCEPTION);
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}
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/* infinities will drop down to the normal compare mechanisms */
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}
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/* First compare for unequal signs => less or greater or
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* special equal case */
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Sgl_xortointp1(left,right,xorresult);
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if( xorresult < 0 )
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{
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/* left negative => less, left positive => greater.
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* equal is possible if both operands are zeros. */
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if( Sgl_iszero_exponentmantissa(left)
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&& Sgl_iszero_exponentmantissa(right) )
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{
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Set_status_cbit(Equal(cond));
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}
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else if( Sgl_isone_sign(left) )
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{
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Set_status_cbit(Lessthan(cond));
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}
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else
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{
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Set_status_cbit(Greaterthan(cond));
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}
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}
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/* Signs are the same. Treat negative numbers separately
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* from the positives because of the reversed sense. */
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else if( Sgl_all(left) == Sgl_all(right) )
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{
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Set_status_cbit(Equal(cond));
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}
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else if( Sgl_iszero_sign(left) )
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{
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/* Positive compare */
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if( Sgl_all(left) < Sgl_all(right) )
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{
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Set_status_cbit(Lessthan(cond));
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}
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else
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{
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Set_status_cbit(Greaterthan(cond));
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}
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}
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else
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{
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/* Negative compare. Signed or unsigned compares
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* both work the same. That distinction is only
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* important when the sign bits differ. */
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if( Sgl_all(left) > Sgl_all(right) )
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{
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Set_status_cbit(Lessthan(cond));
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}
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else
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{
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Set_status_cbit(Greaterthan(cond));
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}
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}
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return(NOEXCEPTION);
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}
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