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[/] [openrisc/] [trunk/] [gnu-src/] [gcc-4.5.1/] [libgcc/] [config/] [libbid/] [bid128_rem.c] - Blame information for rev 280

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1 272 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_div_macros.h"
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BID128_FUNCTION_ARG2_NORND_CUSTOMRESTYPE (UINT128, bid128_rem, x, y)
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     UINT256 P256;
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     UINT128 CX, CY, CX2, CQ, CR, T, CXS, P128, res;
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     UINT64 sign_x, sign_y, valid_y;
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     SINT64 D;
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     int_float f64, fx;
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     int exponent_x, exponent_y, diff_expon, bin_expon_cx, scale,
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       scale0;
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  // unpack arguments, check for NaN or Infinity
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valid_y = unpack_BID128_value (&sign_y, &exponent_y, &CY, y);
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if (!unpack_BID128_value (&sign_x, &exponent_x, &CX, x)) {
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#ifdef SET_STATUS_FLAGS
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if ((y.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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    // test if x is NaN
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if ((x.w[1] & 0x7c00000000000000ull) == 0x7c00000000000000ull) {
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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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  BID_RETURN (res);
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}
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    // x is Infinity?
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if ((x.w[1] & 0x7800000000000000ull) == 0x7800000000000000ull) {
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  // check if y is Inf.
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  if (((y.w[1] & 0x7c00000000000000ull) != 0x7c00000000000000ull))
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    // return NaN 
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  {
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#ifdef SET_STATUS_FLAGS
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    // set status flags
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    __set_status_flags (pfpsf, INVALID_EXCEPTION);
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#endif
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    res.w[1] = 0x7c00000000000000ull;
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    res.w[0] = 0;
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    BID_RETURN (res);
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  }
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}
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    // x is 0
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if ((!CY.w[1]) && (!CY.w[0])) {
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#ifdef SET_STATUS_FLAGS
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  // set status flags
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  __set_status_flags (pfpsf, INVALID_EXCEPTION);
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#endif
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  // x=y=0, return NaN
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  res.w[1] = 0x7c00000000000000ull;
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  res.w[0] = 0;
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  BID_RETURN (res);
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}
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if (valid_y || ((y.w[1] & NAN_MASK64) == INFINITY_MASK64)) {
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  // return 0
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  if ((exponent_x > exponent_y)
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      && ((y.w[1] & NAN_MASK64) != INFINITY_MASK64))
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    exponent_x = exponent_y;
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  res.w[1] = sign_x | (((UINT64) exponent_x) << 49);
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  res.w[0] = 0;
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  BID_RETURN (res);
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}
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}
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if (!valid_y) {
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  // y is Inf. or NaN
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  // test if y is NaN
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  if ((y.w[1] & 0x7c00000000000000ull) == 0x7c00000000000000ull) {
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#ifdef SET_STATUS_FLAGS
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    if ((y.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] = CY.w[1] & QUIET_MASK64;
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    res.w[0] = CY.w[0];
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    BID_RETURN (res);
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  }
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  // y is Infinity?
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  if ((y.w[1] & 0x7800000000000000ull) == 0x7800000000000000ull) {
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    // return x
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    res.w[1] = x.w[1];
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    res.w[0] = x.w[0];
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    BID_RETURN (res);
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  }
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  // y is 0
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#ifdef SET_STATUS_FLAGS
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  // set status flags
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  __set_status_flags (pfpsf, INVALID_EXCEPTION);
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#endif
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  res.w[1] = 0x7c00000000000000ull;
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  res.w[0] = 0;
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  BID_RETURN (res);
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}
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diff_expon = exponent_x - exponent_y;
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if (diff_expon <= 0) {
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  diff_expon = -diff_expon;
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  if (diff_expon > 34) {
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    // |x|<|y| in this case
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    res = x;
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    BID_RETURN (res);
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  }
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  // set exponent of y to exponent_x, scale coefficient_y
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  T = power10_table_128[diff_expon];
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  __mul_128x128_to_256 (P256, CY, T);
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  if (P256.w[2] || P256.w[3]) {
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    // |x|<|y| in this case
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    res = x;
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    BID_RETURN (res);
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  }
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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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  if (__unsigned_compare_ge_128 (P256, CX2)) {
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    // |x|<|y| in this case
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    res = x;
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    BID_RETURN (res);
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  }
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  P128.w[0] = P256.w[0];
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  P128.w[1] = P256.w[1];
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  __div_128_by_128 (&CQ, &CR, CX, P128);
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  CX2.w[1] = (CR.w[1] << 1) | (CR.w[0] >> 63);
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  CX2.w[0] = CR.w[0] << 1;
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  if ((__unsigned_compare_gt_128 (CX2, P256))
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      || (CX2.w[1] == P256.w[1] && CX2.w[0] == P256.w[0]
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          && (CQ.w[0] & 1))) {
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    __sub_128_128 (CR, P256, CR);
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    sign_x ^= 0x8000000000000000ull;
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  }
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  get_BID128_very_fast (&res, sign_x, exponent_x, CR);
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  BID_RETURN (res);
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}
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  // 2^64
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f64.i = 0x5f800000;
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scale0 = 38;
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if (!CY.w[1])
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  scale0 = 34;
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while (diff_expon > 0) {
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  // get number of digits in CX and scale=38-digits
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  // fx ~ CX
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  fx.d = (float) CX.w[1] * f64.d + (float) CX.w[0];
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  bin_expon_cx = ((fx.i >> 23) & 0xff) - 0x7f;
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  scale = scale0 - estimate_decimal_digits[bin_expon_cx];
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  // scale = 38-estimate_decimal_digits[bin_expon_cx];
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  D = CX.w[1] - power10_index_binexp_128[bin_expon_cx].w[1];
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  if (D > 0
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      || (!D && CX.w[0] >= power10_index_binexp_128[bin_expon_cx].w[0]))
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    scale--;
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  if (diff_expon >= scale)
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    diff_expon -= scale;
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  else {
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    scale = diff_expon;
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    diff_expon = 0;
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  }
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  T = power10_table_128[scale];
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  __mul_128x128_low (CXS, CX, T);
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  __div_128_by_128 (&CQ, &CX, CXS, CY);
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  // check for remainder == 0
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  if (!CX.w[1] && !CX.w[0]) {
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    get_BID128_very_fast (&res, sign_x, exponent_y, CX);
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    BID_RETURN (res);
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  }
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}
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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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if ((__unsigned_compare_gt_128 (CX2, CY))
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    || (CX2.w[1] == CY.w[1] && CX2.w[0] == CY.w[0] && (CQ.w[0] & 1))) {
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  __sub_128_128 (CX, CY, CX);
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  sign_x ^= 0x8000000000000000ull;
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}
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get_BID128_very_fast (&res, sign_x, exponent_y, CX);
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BID_RETURN (res);
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}

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