174 lines
6.1 KiB
C
174 lines
6.1 KiB
C
/* $NetBSD: softfloat-specialize.h,v 1.4 1999/05/06 13:56:28 kleink Exp $ */
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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 1a.
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Written by John R. Hauser. This work was made possible by the International
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Computer Science Institute, located at Suite 600, 1947 Center Street,
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Berkeley, California 94704. Funding was provided in part by the National
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Science Foundation under grant MIP-9311980. The original version of
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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://www.cs.berkeley.edu/~jhauser/
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softfloat.html'.
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THIS PACKAGE IS DISTRIBUTED AS IS, FOR FREE. Although reasonable effort has
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been made to avoid it, THIS PACKAGE MAY CONTAIN FAULTS THAT WILL AT TIMES
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RESULT IN INCORRECT BEHAVIOR. USE OF THIS PACKAGE IS RESTRICTED TO PERSONS
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AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ANY AND ALL
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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 three 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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static flag float32_is_signaling_nan( float32 a );
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static flag float64_is_signaling_nan( float64 a );
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/*
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-------------------------------------------------------------------------------
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Underflow tininess-detection mode. (Statically initialized to default.)
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-------------------------------------------------------------------------------
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*/
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static flag float_detect_tininess = float_tininess_after_rounding;
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/*
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-------------------------------------------------------------------------------
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Raises the exceptions specified by `flags'. Floating-point traps can be
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defined here if desired. It is currently not possible for such a trap to
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substitute a result value. If traps are not implemented, this routine
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should be simply `float_exception_flags |= flags;'.
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-------------------------------------------------------------------------------
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*/
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void float_raise( uint8 flags )
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{
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float_exception_flags |= flags;
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}
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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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enum {
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float32_default_nan = 0xFFC00000
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};
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/*
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-------------------------------------------------------------------------------
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The pattern for a default generated double-precision NaN. The `high' and
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`low' words hold the most- and least-significant bits, respectively.
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-------------------------------------------------------------------------------
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*/
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enum {
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float64_default_nan_high = 0xFFF80000,
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float64_default_nan_low = 0x00000000
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};
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/*
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-------------------------------------------------------------------------------
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Returns true if the single-precision floating-point value `a' is a signaling
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NaN; otherwise returns false.
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-------------------------------------------------------------------------------
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*/
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static flag float32_is_signaling_nan( float32 a )
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{
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return ( ( a & 0x7FC00000 ) == 0x7F800000 ) && ( a & 0x003FFFFF );
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}
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/*
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-------------------------------------------------------------------------------
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Returns true if the double-precision floating-point value `a' is a signaling
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NaN; otherwise returns false.
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-------------------------------------------------------------------------------
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*/
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static flag float64_is_signaling_nan( float64 a )
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{
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return
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( ( a.high & 0x7FF80000 ) == 0x7FF00000 )
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&& ( ( a.high & 0x0007FFFF ) || a.low );
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}
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/*
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-------------------------------------------------------------------------------
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Converts a single-precision NaN `a' to a double-precision quiet NaN. If `a'
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is a signaling NaN, the invalid exception is raised.
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-------------------------------------------------------------------------------
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*/
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static float64 float32ToFloat64NaN( float32 a )
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{
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float64 z;
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if ( float32_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
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z.low = float64_default_nan_low;
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z.high = float64_default_nan_high;
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return z;
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}
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/*
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-------------------------------------------------------------------------------
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Converts a double-precision NaN `a' to a single-precision quiet NaN. If `a'
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is a signaling NaN, the invalid exception is raised.
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-------------------------------------------------------------------------------
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*/
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static float32 float64ToFloat32NaN( float64 a )
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{
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if ( float64_is_signaling_nan( a ) ) float_raise( float_flag_invalid );
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return float32_default_nan;
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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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if ( float32_is_signaling_nan( a ) || float32_is_signaling_nan( b ) ) {
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float_raise( float_flag_invalid );
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}
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return float32_default_nan;
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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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float64 z;
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if ( float64_is_signaling_nan( a ) || float64_is_signaling_nan( b ) ) {
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float_raise( float_flag_invalid );
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}
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z.low = float64_default_nan_low;
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z.high = float64_default_nan_high;
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return z;
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}
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