38 lines
1.2 KiB
C
38 lines
1.2 KiB
C
//===-- lib/floatunsidf.c - uint -> double-precision conversion ---*- C -*-===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements unsigned integer to double-precision conversion for the
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// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
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// mode.
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//
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//===----------------------------------------------------------------------===//
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#define DOUBLE_PRECISION
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#include "fp_lib.h"
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fp_t __floatunsidf(unsigned int a) {
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const int aWidth = sizeof a * CHAR_BIT;
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// Handle zero as a special case to protect clz
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if (a == 0) return fromRep(0);
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// Exponent of (fp_t)a is the width of abs(a).
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const int exponent = (aWidth - 1) - __builtin_clz(a);
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rep_t result;
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// Shift a into the significand field and clear the implicit bit.
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const int shift = significandBits - exponent;
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result = (rep_t)a << shift ^ implicitBit;
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// Insert the exponent
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result += (rep_t)(exponent + exponentBias) << significandBits;
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return fromRep(result);
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}
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