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/******************************************************************************
Copyright (c) 2007-2011, Intel Corp.
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
* Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
* Neither the name of Intel Corporation nor the names of its contributors
may be used to endorse or promote products derived from this software
without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
THE POSSIBILITY OF SUCH DAMAGE.
******************************************************************************/
#include "bid_internal.h"
#define MAX_FORMAT_DIGITS 16
#define DECIMAL_EXPONENT_BIAS 398
#define MAX_DECIMAL_EXPONENT 767
BID_TYPE0_FUNCTION_ARGTYPE1_OTHER_ARGTYPE2(BID_UINT64, bid64_scalbn, BID_UINT64, x, int, n)
BID_UINT64 sign_x, coefficient_x, res;
BID_SINT64 exp64;
int exponent_x, rmode;
// unpack arguments, check for NaN or Infinity
if (!unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x)) {
// x is Inf. or NaN or 0
#ifdef BID_SET_STATUS_FLAGS
if ((x & SNAN_MASK64) == SNAN_MASK64) // y is sNaN
__set_status_flags (pfpsf, BID_INVALID_EXCEPTION);
#endif
if (coefficient_x)
res = coefficient_x & QUIET_MASK64;
else {
exp64 = (BID_SINT64) exponent_x + (BID_SINT64) n;
if(exp64<0) exp64=0;
if(exp64>MAX_DECIMAL_EXPONENT) exp64=MAX_DECIMAL_EXPONENT;
exponent_x = exp64;
res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x); // 0
}
BID_RETURN (res);
}
exp64 = (BID_SINT64) exponent_x + (BID_SINT64) n;
exponent_x = exp64;
if ((BID_UINT32) exponent_x <= MAX_DECIMAL_EXPONENT) {
res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x);
BID_RETURN (res);
}
// check for overflow
if (exp64 > MAX_DECIMAL_EXPONENT) {
// try to normalize coefficient
while ((coefficient_x < 1000000000000000ull)
&& (exp64 > MAX_DECIMAL_EXPONENT)) {
// coefficient_x < 10^15, scale by 10
coefficient_x = (coefficient_x << 1) + (coefficient_x << 3);
exponent_x--;
exp64--;
}
if (exp64 <= MAX_DECIMAL_EXPONENT) {
res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x);
BID_RETURN (res);
} else
exponent_x = 0x7fffffff; // overflow
}
// exponent < 0
// the BID pack routine will round the coefficient
rmode = rnd_mode;
res = get_BID64 (sign_x, exponent_x, coefficient_x, rmode, pfpsf);
BID_RETURN (res);
}
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