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[/] [openrisc/] [trunk/] [gnu-dev/] [or1k-gcc/] [libgcc/] [config/] [libbid/] [bid128_scalb.c] - Blame information for rev 801

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1 734 jeremybenn
/* 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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