Adding more bf16 support function + skeleton for f32_to_bf16
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
@@ -118,6 +118,17 @@
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.
*----------------------------------------------------------------------------*/
#define defaultNaNF32UI 0x7FC00000
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 <stdbool.h>
+#include <stdint.h>
+#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 @@
}
/*------------------------------------------------------------------------
*------------------------------------------------------------------------*/
+ // 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
@@ -102,6 +102,17 @@
/*----------------------------------------------------------------------------
*----------------------------------------------------------------------------*/
+#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))
#define expF32UI( a ) ((int_fast16_t) ((a)>>23) & 0xFF)
#define fracF32UI( a ) ((a) & 0x007FFFFF)
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 <stdbool.h>
+#include <stdint.h>
+#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;
+
+}
+
