fixunsdfti.c

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/* ===-- fixunsdfti.c - Implement __fixunsdfti -----------------------------===
 *
 *                     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.
 *
 * ===----------------------------------------------------------------------===
 */
 
#include "fp64.h"
 
typedef unsigned __int128 fixuint_t;
 
fixuint_t ___fixunsdfti(uint64_t a) {
    // Break a into sign, exponent, significand
    const rep_t aRep = a;
    const rep_t aAbs = aRep & absMask;
    const int sign = aRep & signBit ? -1 : 1;
    const int exponent = (aAbs >> significandBits) - exponentBias;
    const rep_t significand = (aAbs & significandMask) | implicitBit;
 
    // If either the value or the exponent is negative, the result is zero.
    if (sign == -1 || exponent < 0)
        return 0;
 
    // If the value is too large for the integer type, saturate.
    if ((unsigned)exponent >= sizeof(fixuint_t) * CHAR_BIT)
        return ~(fixuint_t)0;
 
    // If 0 <= exponent < significandBits, right shift to get the result.
    // Otherwise, shift left.
    if (exponent < significandBits)
        return significand >> (significandBits - exponent);
    else
        return (fixuint_t)significand << (exponent - significandBits);
}