audk/StdLib/LibC/Main/Arm/floatunsidf.c

72 lines
2.5 KiB
C

/**
University of Illinois/NCSA
Open Source License
Copyright (c) 2009-2014 by the contributors listed in CREDITS.TXT
All rights reserved.
Developed by:
LLVM Team
University of Illinois at Urbana-Champaign
http://llvm.org
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal with
the Software without restriction, including without limitation the rights to
use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
of the Software, and to permit persons to whom the Software is furnished to do
so, subject to the following conditions:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimers.
* Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimers in the
documentation and/or other materials provided with the distribution.
* Neither the names of the LLVM Team, University of Illinois at
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS WITH THE
SOFTWARE.
**/
#define DOUBLE_PRECISION
#include "fp_lib.h"
#include "int_lib.h"
ARM_EABI_FNALIAS(ui2d, floatunsidf)
COMPILER_RT_ABI fp_t
__floatunsidf(unsigned int a) {
const int aWidth = sizeof a * CHAR_BIT;
// Handle zero as a special case to protect clz
if (a == 0) return fromRep(0);
// Exponent of (fp_t)a is the width of abs(a).
const int exponent = (aWidth - 1) - __builtin_clz(a);
rep_t result;
// Shift a into the significand field and clear the implicit bit.
const int shift = significandBits - exponent;
result = (rep_t)a << shift ^ implicitBit;
// Insert the exponent
result += (rep_t)(exponent + exponentBias) << significandBits;
return fromRep(result);
}