Viewing file:  bid128_scalb.c (2.8 KB) -rw-r--r--
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/* Copyright (C) 2007-2022 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/>. */
#define BID_128RES
#include "bid_internal.h"
#define DECIMAL_EXPONENT_BIAS_128 6176
#define MAX_DECIMAL_EXPONENT_128 12287
BID128_FUNCTION_ARG128_ARGTYPE2 (bid128_scalb, x, int, n)
UINT128 CX, CX2, CX8, res;
SINT64 exp64;
UINT64 sign_x;
int exponent_x, rmode;
// unpack arguments, check for NaN or Infinity
if (!unpack_BID128_value (&sign_x, &exponent_x, &CX, x)) {
// x is Inf. or NaN or 0
#ifdef SET_STATUS_FLAGS
if ((x.w[1] & SNAN_MASK64) == SNAN_MASK64) // y is sNaN
__set_status_flags (pfpsf, INVALID_EXCEPTION);
#endif
res.w[1] = CX.w[1] & QUIET_MASK64;
res.w[0] = CX.w[0];
if (!CX.w[1]) {
exp64 = (SINT64) exponent_x + (SINT64) n;
if(exp64<0) exp64=0;
if(exp64>MAX_DECIMAL_EXPONENT_128) exp64=MAX_DECIMAL_EXPONENT_128;
exponent_x = exp64;
get_BID128_very_fast (&res, sign_x, exponent_x, CX);
}
BID_RETURN (res);
}
exp64 = (SINT64) exponent_x + (SINT64) n;
exponent_x = exp64;
if ((UINT32) exponent_x <= MAX_DECIMAL_EXPONENT_128) {
get_BID128_very_fast (&res, sign_x, exponent_x, CX);
BID_RETURN (res);
}
// check for overflow
if (exp64 > MAX_DECIMAL_EXPONENT_128) {
if (CX.w[1] < 0x314dc6448d93ull) {
// try to normalize coefficient
do {
CX8.w[1] = (CX.w[1] << 3) | (CX.w[0] >> 61);
CX8.w[0] = CX.w[0] << 3;
CX2.w[1] = (CX.w[1] << 1) | (CX.w[0] >> 63);
CX2.w[0] = CX.w[0] << 1;
__add_128_128 (CX, CX2, CX8);
exponent_x--;
exp64--;
}
while (CX.w[1] < 0x314dc6448d93ull
&& exp64 > MAX_DECIMAL_EXPONENT_128);
}
if (exp64 <= MAX_DECIMAL_EXPONENT_128) {
get_BID128_very_fast (&res, sign_x, exponent_x, CX);
BID_RETURN (res);
} else
exponent_x = 0x7fffffff; // overflow
}
// exponent < 0
// the BID pack routine will round the coefficient
rmode = rnd_mode;
get_BID128 (&res, sign_x, exponent_x, CX, (unsigned int *) &rmode,
pfpsf);
BID_RETURN (res);
}
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