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//===-- lib/floatsisf.c - integer -> single-precision conversion --*- C -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements integer to single-precision conversion for the
// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
// mode.
//
//===----------------------------------------------------------------------===//
#define SINGLE_PRECISION
#include "fp_lib.h"
#include "int_lib.h"
ARM_EABI_FNALIAS(i2f, floatsisf)
COMPILER_RT_ABI fp_t
__floatsisf(int a) {
const int aWidth = sizeof a * CHAR_BIT;
// Handle zero as a special case to protect clz
if (a == 0)
return fromRep(0);
// All other cases begin by extracting the sign and absolute value of a
rep_t sign = 0;
if (a < 0) {
sign = signBit;
a = -a;
}
// 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, rounding if it is a right-shift
if (exponent <= significandBits) {
const int shift = significandBits - exponent;
result = (rep_t)a << shift ^ implicitBit;
} else {
const int shift = exponent - significandBits;
result = (rep_t)a >> shift ^ implicitBit;
rep_t round = (rep_t)a << (typeWidth - shift);
if (round > signBit) result++;
if (round == signBit) result += result & 1;
}
// Insert the exponent
result += (rep_t)(exponent + exponentBias) << significandBits;
// Insert the sign bit and return
return fromRep(result | sign);
}
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