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authorAndrew Waterman <andrew@sifive.com>2018-07-11 01:16:28 -0700
committerAndrew Waterman <andrew@sifive.com>2018-07-11 01:16:28 -0700
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treef6fb9cb6d3bef2aa5c9903511b92e5a6e99e9519 /softfloat/f16_roundToInt.c
parent8e69141749065ff957383d2112768f95a33429b6 (diff)
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Upgrade to SoftFloat 3e
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+
+/*============================================================================
+
+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 "specialize.h"
+#include "softfloat.h"
+
+float16_t f16_roundToInt( float16_t a, uint_fast8_t roundingMode, bool exact )
+{
+ union ui16_f16 uA;
+ uint_fast16_t uiA;
+ int_fast8_t exp;
+ uint_fast16_t uiZ, lastBitMask, roundBitsMask;
+ union ui16_f16 uZ;
+
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ uA.f = a;
+ uiA = uA.ui;
+ exp = expF16UI( uiA );
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ if ( exp <= 0xE ) {
+ if ( !(uint16_t) (uiA<<1) ) return a;
+ if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact );
+ uiZ = uiA & packToF16UI( 1, 0, 0 );
+ switch ( roundingMode ) {
+ case softfloat_round_near_even:
+ if ( !fracF16UI( uiA ) ) break;
+ case softfloat_round_near_maxMag:
+ if ( exp == 0xE ) uiZ |= packToF16UI( 0, 0xF, 0 );
+ break;
+ case softfloat_round_min:
+ if ( uiZ ) uiZ = packToF16UI( 1, 0xF, 0 );
+ break;
+ case softfloat_round_max:
+ if ( !uiZ ) uiZ = packToF16UI( 0, 0xF, 0 );
+ break;
+#ifdef SOFTFLOAT_ROUND_ODD
+ case softfloat_round_odd:
+ uiZ |= packToF16UI( 0, 0xF, 0 );
+ break;
+#endif
+ }
+ goto uiZ;
+ }
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ if ( 0x19 <= exp ) {
+ if ( (exp == 0x1F) && fracF16UI( uiA ) ) {
+ uiZ = softfloat_propagateNaNF16UI( uiA, 0 );
+ goto uiZ;
+ }
+ return a;
+ }
+ /*------------------------------------------------------------------------
+ *------------------------------------------------------------------------*/
+ uiZ = uiA;
+ lastBitMask = (uint_fast16_t) 1<<(0x19 - exp);
+ roundBitsMask = lastBitMask - 1;
+ if ( roundingMode == softfloat_round_near_maxMag ) {
+ uiZ += lastBitMask>>1;
+ } else if ( roundingMode == softfloat_round_near_even ) {
+ uiZ += lastBitMask>>1;
+ if ( !(uiZ & roundBitsMask) ) uiZ &= ~lastBitMask;
+ } else if (
+ roundingMode
+ == (signF16UI( uiZ ) ? softfloat_round_min : softfloat_round_max)
+ ) {
+ uiZ += roundBitsMask;
+ }
+ uiZ &= ~roundBitsMask;
+ if ( uiZ != uiA ) {
+#ifdef SOFTFLOAT_ROUND_ODD
+ if ( roundingMode == softfloat_round_odd ) uiZ |= lastBitMask;
+#endif
+ if ( exact ) softfloat_raiseFlags( softfloat_flag_inexact );
+ }
+ uiZ:
+ uZ.ui = uiZ;
+ return uZ.f;
+
+}
+