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Diffstat (limited to 'softfloat/f128_to_f64.c')
| -rw-r--r-- | softfloat/f128_to_f64.c | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/softfloat/f128_to_f64.c b/softfloat/f128_to_f64.c new file mode 100644 index 0000000..76da76c --- /dev/null +++ b/softfloat/f128_to_f64.c @@ -0,0 +1,100 @@ + +/*============================================================================ + +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" + +float64_t f128_to_f64( float128_t a ) +{ + union ui128_f128 uA; + uint_fast64_t uiA64, uiA0; + bool sign; + int_fast32_t exp; + uint_fast64_t frac64, frac0; + struct commonNaN commonNaN; + uint_fast64_t uiZ; + struct uint128 frac128; + union ui64_f64 uZ; + + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + uA.f = a; + uiA64 = uA.ui.v64; + uiA0 = uA.ui.v0; + sign = signF128UI64( uiA64 ); + exp = expF128UI64( uiA64 ); + frac64 = fracF128UI64( uiA64 ); + frac0 = uiA0; + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + if ( exp == 0x7FFF ) { + if ( frac64 | frac0 ) { + softfloat_f128UIToCommonNaN( uiA64, uiA0, &commonNaN ); + uiZ = softfloat_commonNaNToF64UI( &commonNaN ); + } else { + uiZ = packToF64UI( sign, 0x7FF, 0 ); + } + goto uiZ; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + frac128 = softfloat_shortShiftLeft128( frac64, frac0, 14 ); + frac64 = frac128.v64 | (frac128.v0 != 0); + if ( ! (exp | frac64) ) { + uiZ = packToF64UI( sign, 0, 0 ); + goto uiZ; + } + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + exp -= 0x3C01; + if ( sizeof (int_fast16_t) < sizeof (int_fast32_t) ) { + if ( exp < -0x1000 ) exp = -0x1000; + } + return + softfloat_roundPackToF64( + sign, exp, frac64 | UINT64_C( 0x4000000000000000 ) ); + /*------------------------------------------------------------------------ + *------------------------------------------------------------------------*/ + uiZ: + uZ.ui = uiZ; + return uZ.f; + +} + |