481 lines
16 KiB
C
481 lines
16 KiB
C
/* $NetBSD: softfloat-specialize.h,v 1.2 2008/04/28 20:24:06 martin Exp $ */
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/* This is a derivative work. */
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/*-
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* Copyright (c) 2001 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Ross Harvey.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/*
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===============================================================================
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This C source fragment is part of the SoftFloat IEC/IEEE Floating-point
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Arithmetic Package, Release 2a.
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Written by John R. Hauser. This work was made possible in part by the
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International Computer Science Institute, located at Suite 600, 1947 Center
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Street, Berkeley, California 94704. Funding was partially provided by the
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National Science Foundation under grant MIP-9311980. The original version
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of this code was written as part of a project to build a fixed-point vector
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processor in collaboration with the University of California at Berkeley,
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overseen by Profs. Nelson Morgan and John Wawrzynek. More information
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is available through the Web page `http://HTTP.CS.Berkeley.EDU/~jhauser/
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arithmetic/SoftFloat.html'.
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THIS SOFTWARE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort
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has been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT
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TIMES RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO
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PERSONS AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY
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AND ALL LOSSES, COSTS, OR OTHER PROBLEMS ARISING FROM ITS USE.
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Derivative works are acceptable, even for commercial purposes, so long as
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(1) they include prominent notice that the work is derivative, and (2) they
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include prominent notice akin to these four paragraphs for those parts of
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this code that are retained.
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===============================================================================
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*/
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/*
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-------------------------------------------------------------------------------
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Underflow tininess-detection mode, statically initialized to default value.
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-------------------------------------------------------------------------------
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*/
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/* [ MP safe, does not change dynamically ] */
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int float_detect_tininess = float_tininess_after_rounding;
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/*
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-------------------------------------------------------------------------------
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Internal canonical NaN format.
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-------------------------------------------------------------------------------
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*/
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typedef struct {
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flag sign;
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bits64 high, low;
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} commonNaNT;
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/*
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-------------------------------------------------------------------------------
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The pattern for a default generated single-precision NaN.
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-------------------------------------------------------------------------------
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*/
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#define float32_default_nan 0xFFC00000
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/*
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-------------------------------------------------------------------------------
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Returns 1 if the single-precision floating-point value `a' is a NaN;
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otherwise returns 0.
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-------------------------------------------------------------------------------
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*/
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static flag float32_is_nan( float32 a )
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{
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return ( 0xFF000000 < (bits32) ( a<<1 ) );
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}
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/*
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-------------------------------------------------------------------------------
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Returns 1 if the single-precision floating-point value `a' is a signaling
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NaN; otherwise returns 0.
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-------------------------------------------------------------------------------
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*/
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flag float32_is_signaling_nan( float32 a )
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{
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return ( ( ( a>>22 ) & 0x1FF ) == 0x1FE ) && ( a & 0x003FFFFF );
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}
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/*
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-------------------------------------------------------------------------------
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Returns the result of converting the single-precision floating-point NaN
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`a' to the canonical NaN format. If `a' is a signaling NaN, the invalid
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exception is raised.
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-------------------------------------------------------------------------------
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*/
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static commonNaNT float32ToCommonNaN( float32 a )
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{
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commonNaNT z;
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if ( float32_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
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z.sign = a>>31;
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z.low = 0;
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z.high = ( (bits64) a )<<41;
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return z;
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}
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/*
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-------------------------------------------------------------------------------
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Returns the result of converting the canonical NaN `a' to the single-
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precision floating-point format.
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-------------------------------------------------------------------------------
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*/
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static float32 commonNaNToFloat32( commonNaNT a )
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{
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return ( ( (bits32) a.sign )<<31 ) | 0x7FC00000 | ( a.high>>41 );
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}
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/*
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-------------------------------------------------------------------------------
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Takes two single-precision floating-point values `a' and `b', one of which
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is a NaN, and returns the appropriate NaN result. If either `a' or `b' is a
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signaling NaN, the invalid exception is raised.
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-------------------------------------------------------------------------------
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*/
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static float32 propagateFloat32NaN( float32 a, float32 b )
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{
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flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN;
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aIsNaN = float32_is_nan( a );
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aIsSignalingNaN = float32_is_signaling_nan( a );
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bIsNaN = float32_is_nan( b );
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bIsSignalingNaN = float32_is_signaling_nan( b );
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a |= 0x00400000;
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b |= 0x00400000;
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if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid );
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if ( aIsSignalingNaN ) {
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if ( bIsSignalingNaN ) goto returnLargerSignificand;
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return bIsNaN ? b : a;
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}
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else if ( aIsNaN ) {
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if ( bIsSignalingNaN | ! bIsNaN ) return a;
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returnLargerSignificand:
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if ( (bits32) ( a<<1 ) < (bits32) ( b<<1 ) ) return b;
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if ( (bits32) ( b<<1 ) < (bits32) ( a<<1 ) ) return a;
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return ( a < b ) ? a : b;
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}
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else {
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return b;
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}
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}
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/*
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-------------------------------------------------------------------------------
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Returns the result of converting the double-precision floating-point NaN
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`a' to the canonical NaN format. If `a' is a signaling NaN, the invalid
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exception is raised.
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-------------------------------------------------------------------------------
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*/
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static commonNaNT float64ToCommonNaN( float64 a )
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{
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commonNaNT z;
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if ( float64_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
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z.sign = a>>63;
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z.low = 0;
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z.high = a<<12;
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return z;
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}
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/*
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-------------------------------------------------------------------------------
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Returns the result of converting the canonical NaN `a' to the double-
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precision floating-point format.
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-------------------------------------------------------------------------------
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*/
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static float64 commonNaNToFloat64( commonNaNT a )
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{
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return
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( ( (bits64) a.sign )<<63 )
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| LIT64( 0x7FF8000000000000 )
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| ( a.high>>12 );
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}
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/*
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-------------------------------------------------------------------------------
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Takes two double-precision floating-point values `a' and `b', one of which
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is a NaN, and returns the appropriate NaN result. If either `a' or `b' is a
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signaling NaN, the invalid exception is raised.
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-------------------------------------------------------------------------------
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*/
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static float64 propagateFloat64NaN( float64 a, float64 b )
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{
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flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN;
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aIsNaN = float64_is_nan( a );
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aIsSignalingNaN = float64_is_signaling_nan( a );
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bIsNaN = float64_is_nan( b );
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bIsSignalingNaN = float64_is_signaling_nan( b );
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a |= LIT64( 0x0008000000000000 );
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b |= LIT64( 0x0008000000000000 );
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if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid );
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if ( aIsSignalingNaN ) {
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if ( bIsSignalingNaN ) goto returnLargerSignificand;
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return bIsNaN ? b : a;
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}
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else if ( aIsNaN ) {
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if ( bIsSignalingNaN | ! bIsNaN ) return a;
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returnLargerSignificand:
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if ( (bits64) ( a<<1 ) < (bits64) ( b<<1 ) ) return b;
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if ( (bits64) ( b<<1 ) < (bits64) ( a<<1 ) ) return a;
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return ( a < b ) ? a : b;
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}
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else {
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return b;
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}
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}
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#ifdef FLOATX80
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/*
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-------------------------------------------------------------------------------
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The pattern for a default generated extended double-precision NaN. The
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`high' and `low' values hold the most- and least-significant bits,
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respectively.
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-------------------------------------------------------------------------------
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*/
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#define floatx80_default_nan_high 0xFFFF
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#define floatx80_default_nan_low LIT64( 0xC000000000000000 )
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/*
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-------------------------------------------------------------------------------
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Returns 1 if the extended double-precision floating-point value `a' is a
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NaN; otherwise returns 0.
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-------------------------------------------------------------------------------
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*/
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static flag floatx80_is_nan( floatx80 a )
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{
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return ( ( a.high & 0x7FFF ) == 0x7FFF ) && (bits64) ( a.low<<1 );
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}
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/*
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-------------------------------------------------------------------------------
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Returns 1 if the extended double-precision floating-point value `a' is a
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signaling NaN; otherwise returns 0.
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-------------------------------------------------------------------------------
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*/
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flag floatx80_is_signaling_nan( floatx80 a )
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{
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bits64 aLow;
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aLow = a.low & ~ LIT64( 0x4000000000000000 );
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return
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( ( a.high & 0x7FFF ) == 0x7FFF )
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&& (bits64) ( aLow<<1 )
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&& ( a.low == aLow );
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}
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/*
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-------------------------------------------------------------------------------
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Returns the result of converting the extended double-precision floating-
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point NaN `a' to the canonical NaN format. If `a' is a signaling NaN, the
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invalid exception is raised.
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-------------------------------------------------------------------------------
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*/
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static commonNaNT floatx80ToCommonNaN( floatx80 a )
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{
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commonNaNT z;
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if ( floatx80_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
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z.sign = a.high>>15;
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z.low = 0;
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z.high = a.low<<1;
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return z;
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}
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/*
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-------------------------------------------------------------------------------
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Returns the result of converting the canonical NaN `a' to the extended
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double-precision floating-point format.
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-------------------------------------------------------------------------------
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*/
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static floatx80 commonNaNToFloatx80( commonNaNT a )
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{
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floatx80 z;
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z.low = LIT64( 0xC000000000000000 ) | ( a.high>>1 );
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z.high = ( ( (bits16) a.sign )<<15 ) | 0x7FFF;
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return z;
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}
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/*
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-------------------------------------------------------------------------------
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Takes two extended double-precision floating-point values `a' and `b', one
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of which is a NaN, and returns the appropriate NaN result. If either `a' or
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`b' is a signaling NaN, the invalid exception is raised.
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-------------------------------------------------------------------------------
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*/
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static floatx80 propagateFloatx80NaN( floatx80 a, floatx80 b )
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{
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flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN;
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aIsNaN = floatx80_is_nan( a );
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aIsSignalingNaN = floatx80_is_signaling_nan( a );
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bIsNaN = floatx80_is_nan( b );
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bIsSignalingNaN = floatx80_is_signaling_nan( b );
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a.low |= LIT64( 0xC000000000000000 );
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b.low |= LIT64( 0xC000000000000000 );
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if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid );
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if ( aIsSignalingNaN ) {
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if ( bIsSignalingNaN ) goto returnLargerSignificand;
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return bIsNaN ? b : a;
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}
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else if ( aIsNaN ) {
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if ( bIsSignalingNaN | ! bIsNaN ) return a;
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returnLargerSignificand:
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if ( a.low < b.low ) return b;
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if ( b.low < a.low ) return a;
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return ( a.high < b.high ) ? a : b;
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}
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else {
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return b;
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}
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}
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#endif
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#ifdef FLOAT128
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/*
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-------------------------------------------------------------------------------
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The pattern for a default generated quadruple-precision NaN. The `high' and
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`low' values hold the most- and least-significant bits, respectively.
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-------------------------------------------------------------------------------
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*/
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#define float128_default_nan_high LIT64( 0xFFFF800000000000 )
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#define float128_default_nan_low LIT64( 0x0000000000000000 )
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/*
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-------------------------------------------------------------------------------
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Returns 1 if the quadruple-precision floating-point value `a' is a NaN;
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otherwise returns 0.
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-------------------------------------------------------------------------------
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*/
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flag float128_is_nan( float128 a )
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{
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return
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( LIT64( 0xFFFE000000000000 ) <= (bits64) ( a.high<<1 ) )
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&& ( a.low || ( a.high & LIT64( 0x0000FFFFFFFFFFFF ) ) );
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}
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/*
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-------------------------------------------------------------------------------
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Returns 1 if the quadruple-precision floating-point value `a' is a
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signaling NaN; otherwise returns 0.
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-------------------------------------------------------------------------------
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*/
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flag float128_is_signaling_nan( float128 a )
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{
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return
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( ( ( a.high>>47 ) & 0xFFFF ) == 0xFFFE )
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&& ( a.low || ( a.high & LIT64( 0x00007FFFFFFFFFFF ) ) );
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}
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/*
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-------------------------------------------------------------------------------
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Returns the result of converting the quadruple-precision floating-point NaN
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`a' to the canonical NaN format. If `a' is a signaling NaN, the invalid
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exception is raised.
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-------------------------------------------------------------------------------
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*/
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static commonNaNT float128ToCommonNaN( float128 a )
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{
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commonNaNT z;
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if ( float128_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
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z.sign = a.high>>63;
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shortShift128Left( a.high, a.low, 16, &z.high, &z.low );
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return z;
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}
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/*
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-------------------------------------------------------------------------------
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Returns the result of converting the canonical NaN `a' to the quadruple-
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precision floating-point format.
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-------------------------------------------------------------------------------
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*/
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static float128 commonNaNToFloat128( commonNaNT a )
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{
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float128 z;
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shift128Right( a.high, a.low, 16, &z.high, &z.low );
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z.high |= ( ( (bits64) a.sign )<<63 ) | LIT64( 0x7FFF800000000000 );
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return z;
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}
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/*
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-------------------------------------------------------------------------------
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Takes two quadruple-precision floating-point values `a' and `b', one of
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which is a NaN, and returns the appropriate NaN result. If either `a' or
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`b' is a signaling NaN, the invalid exception is raised.
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-------------------------------------------------------------------------------
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*/
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static float128 propagateFloat128NaN( float128 a, float128 b )
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{
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flag aIsNaN, aIsSignalingNaN, bIsNaN, bIsSignalingNaN;
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aIsNaN = float128_is_nan( a );
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aIsSignalingNaN = float128_is_signaling_nan( a );
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bIsNaN = float128_is_nan( b );
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bIsSignalingNaN = float128_is_signaling_nan( b );
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a.high |= LIT64( 0x0000800000000000 );
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b.high |= LIT64( 0x0000800000000000 );
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if ( aIsSignalingNaN | bIsSignalingNaN ) float_raise( float_flag_invalid );
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if ( aIsSignalingNaN ) {
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if ( bIsSignalingNaN ) goto returnLargerSignificand;
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return bIsNaN ? b : a;
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}
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else if ( aIsNaN ) {
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if ( bIsSignalingNaN | ! bIsNaN ) return a;
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returnLargerSignificand:
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if ( lt128( a.high<<1, a.low, b.high<<1, b.low ) ) return b;
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if ( lt128( b.high<<1, b.low, a.high<<1, a.low ) ) return a;
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return ( a.high < b.high ) ? a : b;
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}
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else {
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return b;
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}
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}
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#endif
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