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342 lines
14 KiB
C
342 lines
14 KiB
C
/* SoftFloat-specialize.h (C) John R. Hauser, 1998-2002 */
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/* (C) Copyright "Fish" (David B. Trout), 2011 */
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/* This module is part of the SoftFloat package. */
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/* */
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/* Released under "The Q Public License Version 1" */
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/* (http://www.hercules-390.org/herclic.html) */
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/* as modifications to Hercules. */
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/* This module is a SLIGHTLY modified version of John R. Hauser's */
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/* 'SoftFloat-specialize.h', and is largely copyright by him. All */
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/* I (i.e. "Fish", David B. Trout) did was enhance it to interface */
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/* with the Hercules emulator by passing along a void* pointer to */
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/* a generic "context" structure rather than use global variables */
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/* the way it was originally written. It is 99.9999% John's work. */
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/* Refer to the documents "SoftFloat.txt", "SoftFloat-source.txt", */
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/* and "SoftFloat-history.txt" for detailed SoftFloat information. */
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/* Fish note: 'FLOATX80' support was removed as we don't need it. */
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/* SoftFloat was repackaged to reside in the main source path */
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/* to provide FULL CROSS PLATFORM build compatibility. */
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/* To make evident the SoftFloat rePackaging standardized names */
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/* were used */
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/* mileu.h was renamed to SoftFloat-milieu.h and all the sources */
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/* were modified accordingly. */
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/* no other modifications were made */
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/* no reason to clutter the copyright stuff for such a minor change */
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/* */
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/* the original unmodified SoftFloat package is still distributed */
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/* in zipped format here as SoftFloat-2b.zip */
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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 2b.
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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://www.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 has
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been made to avoid it, THIS SOFTWARE MAY CONTAIN FAULTS THAT WILL AT TIMES
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RESULT IN INCORRECT BEHAVIOR. USE OF THIS SOFTWARE IS RESTRICTED TO PERSONS
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AND ORGANIZATIONS WHO CAN AND WILL TAKE FULL RESPONSIBILITY FOR ALL LOSSES,
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COSTS, OR OTHER PROBLEMS THEY INCUR DUE TO THE SOFTWARE, AND WHO FURTHERMORE
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EFFECTIVELY INDEMNIFY JOHN HAUSER AND THE INTERNATIONAL COMPUTER SCIENCE
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INSTITUTE (possibly via similar legal warning) AGAINST ALL LOSSES, COSTS, OR
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OTHER PROBLEMS INCURRED BY THEIR CUSTOMERS AND CLIENTS DUE TO THE SOFTWARE.
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Derivative works are acceptable, even for commercial purposes, so long as
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(1) the source code for the derivative work includes prominent notice that
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the work is derivative, and (2) the source code includes prominent notice with
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these four paragraphs for those parts of this code that are retained.
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=============================================================================*/
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/*----------------------------------------------------------------------------
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| Internal canonical NaN format.
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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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| The pattern for a default generated single-precision NaN.
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*----------------------------------------------------------------------------*/
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#define float32_default_nan 0xFFC00000
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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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static INLINE 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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| 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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static INLINE 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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| 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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static commonNaNT float32ToCommonNaN( void* ctx, float32 a )
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{
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commonNaNT z;
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if ( float32_is_signaling_nan( a ) ) float_raise( ctx, 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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| 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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static INLINE 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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| 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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static float32 propagateFloat32NaN( void* ctx, 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( ctx, 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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| The pattern for a default generated double-precision NaN.
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*----------------------------------------------------------------------------*/
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#define float64_default_nan LIT64( 0xFFF8000000000000 )
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/*----------------------------------------------------------------------------
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| Returns 1 if the double-precision floating-point value `a' is a NaN;
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| otherwise returns 0.
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*----------------------------------------------------------------------------*/
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static INLINE flag float64_is_nan( float64 a )
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{
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return ( LIT64( 0xFFE0000000000000 ) < (bits64) ( a<<1 ) );
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}
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/*----------------------------------------------------------------------------
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| Returns 1 if the double-precision floating-point value `a' is a signaling
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| NaN; otherwise returns 0.
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*----------------------------------------------------------------------------*/
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static INLINE flag float64_is_signaling_nan( float64 a )
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{
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return
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( ( ( a>>51 ) & 0xFFF ) == 0xFFE )
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&& ( a & LIT64( 0x0007FFFFFFFFFFFF ) );
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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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static commonNaNT float64ToCommonNaN( void* ctx, float64 a )
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{
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commonNaNT z;
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if ( float64_is_signaling_nan( a ) ) float_raise( ctx, 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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| 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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static INLINE 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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| 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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static float64 propagateFloat64NaN( void* ctx, 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( ctx, 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 FLOAT128
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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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#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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| 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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static INLINE 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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| 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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static INLINE 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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| 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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static commonNaNT float128ToCommonNaN( void* ctx, float128 a )
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{
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commonNaNT z;
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if ( float128_is_signaling_nan( a ) ) float_raise( ctx, 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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| 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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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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| 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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static float128 propagateFloat128NaN( void* ctx, 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( ctx, 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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