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/* Copyright (C) 2007, 2009 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
Under Section 7 of GPL version 3, you are granted additional
permissions described in the GCC Runtime Library Exception, version
3.1, as published by the Free Software Foundation.
You should have received a copy of the GNU General Public License and
a copy of the GCC Runtime Library Exception along with this program;
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
<http://www.gnu.org/licenses/>. */
#include "bid_internal.h"
#define MAX_FORMAT_DIGITS 16
#define DECIMAL_EXPONENT_BIAS 398
#define MAX_DECIMAL_EXPONENT 767
#if DECIMAL_CALL_BY_REFERENCE
void
bid64_scalb (UINT64 * pres, UINT64 * px,
int *pn _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
_EXC_INFO_PARAM) {
UINT64 x;
int n;
#else
UINT64
bid64_scalb (UINT64 x,
int n _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM
_EXC_INFO_PARAM) {
#endif
UINT64 sign_x, coefficient_x, res;
SINT64 exp64;
int exponent_x, rmode;
#if DECIMAL_CALL_BY_REFERENCE
#if !DECIMAL_GLOBAL_ROUNDING
_IDEC_round rnd_mode = *prnd_mode;
#endif
x = *px;
n = *pn;
#endif
// 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 SET_STATUS_FLAGS
if ((x & SNAN_MASK64) == SNAN_MASK64) // y is sNaN
__set_status_flags (pfpsf, INVALID_EXCEPTION);
#endif
if (coefficient_x)
res = coefficient_x & QUIET_MASK64;
else {
exp64 = (SINT64) exponent_x + (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 = (SINT64) exponent_x + (SINT64) n;
exponent_x = exp64;
if ((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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