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/*
* Copyright (c) 2014-2018, NVIDIA CORPORATION. All rights reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
#include <stdint.h>
#include "mthdecls.h"
typedef union {
double f;
uint64_t i;
} FPI;
#define EXPBIAS 1023
#define MANTBITS 52
#define GET_EXP(u) (int64_t)(((u)&0x7ff0000000000000) >> MANTBITS)
double
__mth_i_dint(double xx)
{
int64_t xexp;
uint64_t ux, mask;
double x;
FPI fpi;
x = xx;
fpi.f = x;
ux = fpi.i;
xexp = GET_EXP(ux) - EXPBIAS;
if (xexp < 0) {
/* |x| < 0 => zero with the original sign */
fpi.i = (ux & 0x8000000000000000);
} else if (xexp < MANTBITS) {
/* 1 <= |x| < 2^53:
* just mask out the trailing bits of the mantiassa beyond the
* range of the exponent; mask out the exponent field as well.
*/
mask = ((uint64_t)1 << (MANTBITS - xexp)) - 1;
fpi.i = ux & ~mask;
}
/* else illegal input, nan, inf, overflow, ...; just return it */
return fpi.f;
}
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