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97 lines
2.8 KiB
C
97 lines
2.8 KiB
C
/* Copyright (C) 2007, 2009 Free Software Foundation, Inc.
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This file is part of GCC.
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GCC is free software; you can redistribute it and/or modify it under
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the terms of the GNU General Public License as published by the Free
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Software Foundation; either version 3, or (at your option) any later
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version.
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GCC is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#define BID_128RES
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#include "bid_internal.h"
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#define DECIMAL_EXPONENT_BIAS_128 6176
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#define MAX_DECIMAL_EXPONENT_128 12287
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BID128_FUNCTION_ARG128_ARGTYPE2 (bid128_scalb, x, int, n)
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UINT128 CX, CX2, CX8, res;
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SINT64 exp64;
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UINT64 sign_x;
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int exponent_x, rmode;
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// unpack arguments, check for NaN or Infinity
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if (!unpack_BID128_value (&sign_x, &exponent_x, &CX, x)) {
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// x is Inf. or NaN or 0
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#ifdef SET_STATUS_FLAGS
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if ((x.w[1] & SNAN_MASK64) == SNAN_MASK64) // y is sNaN
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__set_status_flags (pfpsf, INVALID_EXCEPTION);
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#endif
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res.w[1] = CX.w[1] & QUIET_MASK64;
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res.w[0] = CX.w[0];
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if (!CX.w[1]) {
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exp64 = (SINT64) exponent_x + (SINT64) n;
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if(exp64<0) exp64=0;
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if(exp64>MAX_DECIMAL_EXPONENT_128) exp64=MAX_DECIMAL_EXPONENT_128;
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exponent_x = exp64;
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get_BID128_very_fast (&res, sign_x, exponent_x, CX);
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}
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BID_RETURN (res);
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}
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exp64 = (SINT64) exponent_x + (SINT64) n;
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exponent_x = exp64;
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if ((UINT32) exponent_x <= MAX_DECIMAL_EXPONENT_128) {
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get_BID128_very_fast (&res, sign_x, exponent_x, CX);
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BID_RETURN (res);
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}
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// check for overflow
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if (exp64 > MAX_DECIMAL_EXPONENT_128) {
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if (CX.w[1] < 0x314dc6448d93ull) {
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// try to normalize coefficient
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do {
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CX8.w[1] = (CX.w[1] << 3) | (CX.w[0] >> 61);
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CX8.w[0] = CX.w[0] << 3;
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CX2.w[1] = (CX.w[1] << 1) | (CX.w[0] >> 63);
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CX2.w[0] = CX.w[0] << 1;
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__add_128_128 (CX, CX2, CX8);
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exponent_x--;
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exp64--;
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}
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while (CX.w[1] < 0x314dc6448d93ull
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&& exp64 > MAX_DECIMAL_EXPONENT_128);
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}
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if (exp64 <= MAX_DECIMAL_EXPONENT_128) {
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get_BID128_very_fast (&res, sign_x, exponent_x, CX);
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BID_RETURN (res);
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} else
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exponent_x = 0x7fffffff; // overflow
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}
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// exponent < 0
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// the BID pack routine will round the coefficient
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rmode = rnd_mode;
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get_BID128 (&res, sign_x, exponent_x, CX, (unsigned int *) &rmode,
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pfpsf);
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BID_RETURN (res);
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}
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