llvm-project

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//===-- lib/floatsidf.c - integer -> double-precision conversion --*- C -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file implements 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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#include "int_lib.h"
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COMPILER_RT_ABI fp_t __floatsidf(si_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)
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    return fromRep(0);
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  // All other cases begin by extracting the sign and absolute value of a
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  rep_t sign = 0;
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  su_int aAbs = (su_int)a;
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  if (a < 0) {
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    sign = signBit;
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    aAbs = -aAbs;
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  }
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  // Exponent of (fp_t)a is the width of abs(a).
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  const int exponent = (aWidth - 1) - clzsi(aAbs);
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  rep_t result;
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  // Shift a into the significand field and clear the implicit bit.  Extra
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  // cast to unsigned int is necessary to get the correct behavior for
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  // the input INT_MIN.
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  const int shift = significandBits - exponent;
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  result = (rep_t)aAbs << shift ^ implicitBit;
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  // Insert the exponent
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  result += (rep_t)(exponent + exponentBias) << significandBits;
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  // Insert the sign bit and return
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  return fromRep(result | sign);
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}
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#if defined(__ARM_EABI__)
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#if defined(COMPILER_RT_ARMHF_TARGET)
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AEABI_RTABI fp_t __aeabi_i2d(si_int a) { return __floatsidf(a); }
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#else
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COMPILER_RT_ALIAS(__floatsidf, __aeabi_i2d)
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#endif
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#endif
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