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Implement f8_to_f16 and f16_to_f8 conversion functions
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‎softfloat/f16_to_f8.c‎

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/*============================================================================
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This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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Package, Release 3d, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of
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California. All rights reserved.
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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 are met:
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1. Redistributions of source code must retain the above copyright notice,
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this list of conditions, and the following disclaimer.
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2. Redistributions in binary form must reproduce the above copyright notice,
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this list of conditions, and the following disclaimer in the documentation
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and/or other materials provided with the distribution.
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3. Neither the name of the University nor the names of its contributors may
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be used to endorse or promote products derived from this software without
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specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
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EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
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DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
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DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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=============================================================================*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "platform.h"
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#include "internals.h"
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#include "specialize.h"
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#include "softfloat.h"
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float8_t f16_to_f8( float16_t a )
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{
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union ui16_f16 uA;
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uint_fast16_t uiA;
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bool sign;
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int_fast8_t exp;
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uint_fast16_t frac;
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struct commonNaN commonNaN;
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uint_fast8_t uiZ;
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uint_fast16_t frac8;
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union ui8_f8 uZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uA.f = a;
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uiA = uA.ui;
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sign = signF16UI( uiA );
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exp = expF16UI( uiA );
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frac = fracF16UI( uiA );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( exp == 0xFF ) {
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if ( frac ) {
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softfloat_f16UIToCommonNaN( uiA, &commonNaN );
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uiZ = softfloat_commonNaNToF8UI( &commonNaN );
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} else {
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uiZ = signInfF8UI( sign );
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}
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goto uiZ;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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frac8 = frac>>2 | ((frac & 0x3) != 0); // Round and preserve sticky bit
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if ( ! (exp | frac8) ) {
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uiZ = packToF8UI( 0, 0, 0 ); // zero
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goto uiZ;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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return softfloat_roundPackToF8( sign, exp - 0xC, frac8 | 0x100 );
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uiZ:
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uZ.ui = uiZ;
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return uZ.f;
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}
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‎softfloat/f8_to_f16.c‎

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/*============================================================================
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This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
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Package, Release 3d, by John R. Hauser.
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Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of
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California. All rights reserved.
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10+
Redistribution and use in source and binary forms, with or without
11+
modification, are permitted provided that the following conditions are met:
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13+
1. Redistributions of source code must retain the above copyright notice,
14+
this list of conditions, and the following disclaimer.
15+
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2. Redistributions in binary form must reproduce the above copyright notice,
17+
this list of conditions, and the following disclaimer in the documentation
18+
and/or other materials provided with the distribution.
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3. Neither the name of the University nor the names of its contributors may
21+
be used to endorse or promote products derived from this software without
22+
specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY
25+
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
26+
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
27+
DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY
28+
DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
29+
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30+
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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=============================================================================*/
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#include <stdbool.h>
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#include <stdint.h>
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#include "platform.h"
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#include "internals.h"
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#include "specialize.h"
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#include "softfloat.h"
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float16_t f8_to_f16( float8_t a )
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{
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union ui8_f8 uA;
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uint_fast8_t uiA;
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bool sign;
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int_fast8_t exp;
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uint_fast8_t frac;
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uint_fast16_t uiZ;
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struct exp8_sig8 normExpSig;
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union ui16_f16 uZ;
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uA.f = a;
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uiA = uA.ui;
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sign = signF8UI( uiA );
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exp = expF8UI( uiA );
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frac = fracF8UI( uiA );
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( isNaNF8UI(uiA) ) {
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uiZ = defaultNaNF16UI;
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goto uiZ;
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}
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if ( isInfF8UI(uiA) ) {
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uiZ = packToF16UI( sign, 0x1F, 0 );
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goto uiZ;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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if ( ! exp ) {
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if ( ! frac ) {
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uiZ = packToF16UI( 0, 0, 0 );
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goto uiZ;
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}
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normExpSig = softfloat_normSubnormalF8Sig( frac );
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exp = normExpSig.exp - 1;
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frac = normExpSig.sig;
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}
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/*------------------------------------------------------------------------
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*------------------------------------------------------------------------*/
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uiZ = packToF16UI( sign, exp + 0xB, (uint_fast16_t) frac<<6 );
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uiZ:
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uZ.ui = uiZ;
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return uZ.f;
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}
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‎softfloat/softfloat.h‎

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@@ -140,6 +140,11 @@ float128_t i64_to_f128( int64_t );
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void i64_to_extF80M( int64_t, extFloat80_t * );
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void i64_to_f128M( int64_t, float128_t * );
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/*----------------------------------------------------------------------------
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| 8-bit (half-precision) floating-point operations.
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*----------------------------------------------------------------------------*/
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float16_t f8_to_f16( float8_t );
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/*----------------------------------------------------------------------------
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| 16-bit (half-precision) floating-point operations.
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*----------------------------------------------------------------------------*/
@@ -155,6 +160,7 @@ uint_fast32_t f16_to_ui32_r_minMag( float16_t, bool );
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uint_fast64_t f16_to_ui64_r_minMag( float16_t, bool );
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int_fast32_t f16_to_i32_r_minMag( float16_t, bool );
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int_fast64_t f16_to_i64_r_minMag( float16_t, bool );
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float8_t f16_to_f8( float16_t );
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float32_t f16_to_f32( float16_t );
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float64_t f16_to_f64( float16_t );
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#ifdef SOFTFLOAT_FAST_INT64

‎softfloat/softfloat.mk.in‎

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@@ -52,7 +52,9 @@ softfloat_c_srcs = \
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f16_roundToInt.c \
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f16_sqrt.c \
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f16_sub.c \
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f16_to_f8.c \
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f16_to_f128.c \
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f8_to_f16.c \
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f16_to_f32.c \
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f16_to_f64.c \
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f16_to_i8.c \

‎softfloat/specialize.h‎

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@@ -103,6 +103,12 @@ struct commonNaN { char _unused; };
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*----------------------------------------------------------------------------*/
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#define defaultNaNBF16UI 0x7FC0
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/*----------------------------------------------------------------------------
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| Converts the common NaN pointed to by `aPtr' into a 8-bit floating-point
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| NaN, and returns the bit pattern of this value as an unsigned integer.
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*----------------------------------------------------------------------------*/
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#define softfloat_commonNaNToF8UI( aPtr ) ((uint_fast8_t) defaultNaNF8UI)
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/*----------------------------------------------------------------------------
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| Returns true when 16-bit unsigned integer `uiA' has the bit pattern of a
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| 16-bit floating-point signaling NaN.

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