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authorAndrew Waterman <andrew@sifive.com>2017-09-24 20:25:34 -0700
committerAndrew Waterman <andrew@sifive.com>2017-09-24 20:25:34 -0700
commitbd85811c35ea38180d27440507fc222d585ef780 (patch)
tree214c6b615d7775f73da5ff9a94bd4a0a2772f9cf /softfloat/s_roundPackToF16.c
parentb86f2a51f522f020ad0d90f598f4c501f41da232 (diff)
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Update SoftFloat
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diff --git a/softfloat/s_roundPackToF16.c b/softfloat/s_roundPackToF16.c
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+
+/*============================================================================
+
+This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic
+Package, Release 3d, 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"
+
+float16_t
+ softfloat_roundPackToF16( 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_f16 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;
+
+}
+