diff --git a/source/RISCV/specialize.h b/source/RISCV/specialize.h index 70fb808..4137bd7 100644 --- a/source/RISCV/specialize.h +++ b/source/RISCV/specialize.h @@ -117,6 +117,17 @@ struct commonNaN { char _unused; }; uint_fast16_t softfloat_propagateNaNF16UI( uint_fast16_t uiA, uint_fast16_t uiB ); +/*---------------------------------------------------------------------------- +| The bit pattern for a default generated 16-bit BF16 floating-point NaN. +*----------------------------------------------------------------------------*/ +#define defaultNaNF16UI 0x7FC0 + +/*---------------------------------------------------------------------------- +| Converts the common NaN pointed to by 'aPtr' into a 16-bit floating-point +| NaN, and returns the bit pattern of this value as an unsigned integer. +*----------------------------------------------------------------------------*/ +#define softfloat_commonNaNToBF16UI( aPtr ) ((uint_fast16_t) defaultNaNBF16UI) + /*---------------------------------------------------------------------------- | The bit pattern for a default generated 32-bit floating-point NaN. *----------------------------------------------------------------------------*/ diff --git a/source/f32_to_bf16.c b/source/f32_to_bf16.c new file mode 100644 index 0000000..82d9b16 --- /dev/null +++ b/source/f32_to_bf16.c @@ -0,0 +1,91 @@ + +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3e, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014, 2015 The Regents of the University of +California. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + 1. Redistributions of source code must retain the above copyright notice, + this list of conditions, and the following disclaimer. + + 2. Redistributions in binary form must reproduce the above copyright notice, + this list of conditions, and the following disclaimer in the documentation + and/or other materials provided with the distribution. + + 3. Neither the name of the University nor the names of its contributors may + be used to endorse or promote products derived from this software without + specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY +EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE +DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY +DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +=============================================================================*/ + +#include +#include +#include "platform.h" +#include "internals.h" +#include "specialize.h" +#include "softfloat.h" + +bfloat16_t f32_to_bf16( float32_t a ) +{ + union ui32_f32 uA; + uint_fast32_t uiA; + bool sign; + int_fast16_t exp; + uint_fast32_t frac; + struct commonNaN commonNaN; + uint_fast16_t uiZ, frac16; + union ui16_bf16 uZ; + + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + uA.f = a; + uiA = uA.ui; + sign = signF32UI( uiA ); + exp = expF32UI( uiA ); + frac = fracF32UI( uiA ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + // infinity or NaN cases + if ( exp == 0xFF ) { + if ( frac ) { + // NaN case + softfloat_f32UIToCommonNaN( uiA, &commonNaN ); + uiZ = softfloat_commonNaNToBF16UI( &commonNaN ); + } else { + // infinity case + uiZ = packToBF16UI( sign, 0xFF, 0 ); + } + goto uiZ; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + frac16 = frac>>16 | ((frac & 0xFFFF) != 0); + if ( ! (exp | frac16) ) { + uiZ = packToBF16UI( sign, 0, 0 ); + goto uiZ; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + return softfloat_roundPackToBF16( sign, exp, frac16 | 0x4000 ); + uiZ: + uZ.ui = uiZ; + return uZ.f; + +} + diff --git a/source/f32_to_f16.c b/source/f32_to_f16.c index a00b2e8..45005fe 100644 --- a/source/f32_to_f16.c +++ b/source/f32_to_f16.c @@ -72,6 +72,9 @@ float16_t f32_to_f16( float32_t a ) } /*------------------------------------------------------------------------ *------------------------------------------------------------------------*/ + // frac is a 24-bit significand, the bottom 9 bits LSB are extracted and OR-red + // into a sticky flag, the top 15 MSBs are extracted, the LSB of this top slice + // is OR-red with the sticky frac16 = frac>>9 | ((frac & 0x1FF) != 0); if ( ! (exp | frac16) ) { uiZ = packToF16UI( sign, 0, 0 ); diff --git a/source/include/internals.h b/source/include/internals.h index ccd7747..ea14a7d 100644 --- a/source/include/internals.h +++ b/source/include/internals.h @@ -100,6 +100,17 @@ float16_t softfloat_mulAddF16( uint_fast16_t, uint_fast16_t, uint_fast16_t, uint_fast8_t ); +/*---------------------------------------------------------------------------- +*----------------------------------------------------------------------------*/ +#define signBF16UI( a ) ((bool) ((uint16_t) (a)>>15)) +#define expBF16UI( a ) ((int_fast8_t) ((a)>>7) & 0xFF) +#define fracBF16UI( a ) ((a) & 0x07F) +#define packToBF16UI( sign, exp, sig ) (((uint16_t) (sign)<<15) + ((uint16_t) (exp)<<7) + (sig)) + +#define isNaNBF16UI( a ) (((~(a) & 0x7FC0) == 0) && ((a) & 0x07F)) + +bfloat16_t softfloat_roundPackToBF16( bool, int_fast16_t, uint_fast16_t ); + /*---------------------------------------------------------------------------- *----------------------------------------------------------------------------*/ #define signF32UI( a ) ((bool) ((uint32_t) (a)>>31)) diff --git a/source/s_roundPackToBF16.c b/source/s_roundPackToBF16.c new file mode 100644 index 0000000..66e19be --- /dev/null +++ b/source/s_roundPackToBF16.c @@ -0,0 +1,113 @@ + +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3e, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014, 2015, 2017 The Regents of the University of +California. All rights reserved. + +Redistribution and use in source and binary forms, with or without +modification, are permitted provided that the following conditions are met: + + 1. Redistributions of source code must retain the above copyright notice, + this list of conditions, and the following disclaimer. + + 2. Redistributions in binary form must reproduce the above copyright notice, + this list of conditions, and the following disclaimer in the documentation + and/or other materials provided with the distribution. + + 3. Neither the name of the University nor the names of its contributors may + be used to endorse or promote products derived from this software without + specific prior written permission. + +THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS", AND ANY +EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED +WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE +DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE FOR ANY +DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES +(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND +ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS +SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + +=============================================================================*/ + +#include +#include +#include "platform.h" +#include "internals.h" +#include "softfloat.h" + +bfloat16_t + softfloat_roundPackToBF16( bool sign, int_fast16_t exp, uint_fast16_t sig ) +{ + uint_fast8_t roundingMode; + bool roundNearEven; + uint_fast8_t roundIncrement, roundBits; + bool isTiny; + uint_fast16_t uiZ; + union ui16_bf16 uZ; + + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + roundingMode = softfloat_roundingMode; + roundNearEven = (roundingMode == softfloat_round_near_even); + roundIncrement = 0x8; + if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { + roundIncrement = + (roundingMode + == (sign ? softfloat_round_min : softfloat_round_max)) + ? 0xF + : 0; + } + roundBits = sig & 0xF; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( 0x1D <= (unsigned int) exp ) { + if ( exp < 0 ) { + /*---------------------------------------------------------------- + *----------------------------------------------------------------*/ + isTiny = + (softfloat_detectTininess == softfloat_tininess_beforeRounding) + || (exp < -1) || (sig + roundIncrement < 0x8000); + sig = softfloat_shiftRightJam32( sig, -exp ); + exp = 0; + roundBits = sig & 0xF; + if ( isTiny && roundBits ) { + softfloat_raiseFlags( softfloat_flag_underflow ); + } + } else if ( (0x1D < exp) || (0x8000 <= sig + roundIncrement) ) { + /*---------------------------------------------------------------- + *----------------------------------------------------------------*/ + softfloat_raiseFlags( + softfloat_flag_overflow | softfloat_flag_inexact ); + uiZ = packToF16UI( sign, 0x1F, 0 ) - ! roundIncrement; + goto uiZ; + } + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + sig = (sig + roundIncrement)>>4; + if ( roundBits ) { + softfloat_exceptionFlags |= softfloat_flag_inexact; +#ifdef SOFTFLOAT_ROUND_ODD + if ( roundingMode == softfloat_round_odd ) { + sig |= 1; + goto packReturn; + } +#endif + } + sig &= ~(uint_fast16_t) (! (roundBits ^ 8) & roundNearEven); + if ( ! sig ) exp = 0; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + packReturn: + uiZ = packToF16UI( sign, exp, sig ); + uiZ: + uZ.ui = uiZ; + return uZ.f; + +} +