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Diffstat (limited to 'source/s_roundToI64.c')
-rw-r--r-- | source/s_roundToI64.c | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/source/s_roundToI64.c b/source/s_roundToI64.c new file mode 100644 index 0000000..0d60a18 --- /dev/null +++ b/source/s_roundToI64.c @@ -0,0 +1,89 @@ + +/*============================================================================ + +This C source file is part of the SoftFloat IEEE Floating-Point Arithmetic +Package, Release 3c, by John R. Hauser. + +Copyright 2011, 2012, 2013, 2014, 2015, 2016, 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" + +int_fast64_t + softfloat_roundToI64( + bool sign, + uint_fast64_t sig, + uint_fast64_t sigExtra, + uint_fast8_t roundingMode, + bool exact + ) +{ + bool roundNearEven, doIncrement; + union { uint64_t ui; int64_t i; } uZ; + int_fast64_t z; + + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + roundNearEven = (roundingMode == softfloat_round_near_even); + doIncrement = (UINT64_C( 0x8000000000000000 ) <= sigExtra); + if ( ! roundNearEven && (roundingMode != softfloat_round_near_maxMag) ) { + doIncrement = + (roundingMode + == (sign ? softfloat_round_min : softfloat_round_max)) + && sigExtra; + } + if ( doIncrement ) { + ++sig; + if ( ! sig ) goto invalid; + sig &= + ~(uint_fast64_t) + (! (sigExtra & UINT64_C( 0x7FFFFFFFFFFFFFFF )) + & roundNearEven); + } + uZ.ui = sign ? -sig : sig; + z = uZ.i; + if ( z && ((z < 0) ^ sign) ) goto invalid; + if ( exact && sigExtra ) { + softfloat_exceptionFlags |= softfloat_flag_inexact; + } + return z; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + invalid: + softfloat_raiseFlags( softfloat_flag_invalid ); + return sign ? i64_fromNegOverflow : i64_fromPosOverflow; + +} + |