mirror of
https://github.com/autc04/Retro68.git
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275 lines
7.8 KiB
C
275 lines
7.8 KiB
C
/* Copyright (C) 2007-2016 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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BID128_FUNCTION_ARG2 (bid128_quantize, x, y)
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UINT256 CT;
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UINT128 CX, CY, T, CX2, CR, Stemp, res, REM_H, C2N;
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UINT64 sign_x, sign_y, remainder_h, carry, CY64, valid_x;
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int_float tempx;
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int exponent_x, exponent_y, digits_x, extra_digits, amount;
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int expon_diff, total_digits, bin_expon_cx, rmode, status;
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valid_x = unpack_BID128_value (&sign_x, &exponent_x, &CX, x);
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// unpack arguments, check for NaN or Infinity
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if (!unpack_BID128_value (&sign_y, &exponent_y, &CY, y)) {
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// y is Inf. or NaN
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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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// 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] & 0x7e00000000000000ull) == 0x7e00000000000000ull) {
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// set status flags
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__set_status_flags (pfpsf, INVALID_EXCEPTION);
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}
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#endif
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if ((x.w[1] & 0x7c00000000000000ull) != 0x7c00000000000000ull) {
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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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} else {
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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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}
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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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// check if x is not Inf.
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if (((x.w[1] & 0x7c00000000000000ull) < 0x7800000000000000ull)) {
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// return NaN
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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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} else
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if (((x.w[1] & 0x7c00000000000000ull) <= 0x7800000000000000ull)) {
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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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}
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}
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if (!valid_x) {
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// test if x is NaN or Inf
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if ((x.w[1] & 0x7c00000000000000ull) == 0x7800000000000000ull) {
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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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} else if ((x.w[1] & 0x7c00000000000000ull) == 0x7c00000000000000ull) {
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if ((x.w[1] & 0x7e00000000000000ull) == 0x7e00000000000000ull) {
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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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}
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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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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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// get number of decimal digits in coefficient_x
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if (CX.w[1]) {
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tempx.d = (float) CX.w[1];
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bin_expon_cx = ((tempx.i >> 23) & 0xff) - 0x7f + 64;
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} else {
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tempx.d = (float) CX.w[0];
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bin_expon_cx = ((tempx.i >> 23) & 0xff) - 0x7f;
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}
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digits_x = estimate_decimal_digits[bin_expon_cx];
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if (CX.w[1] > power10_table_128[digits_x].w[1]
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|| (CX.w[1] == power10_table_128[digits_x].w[1]
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&& CX.w[0] >= power10_table_128[digits_x].w[0]))
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digits_x++;
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expon_diff = exponent_x - exponent_y;
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total_digits = digits_x + expon_diff;
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if ((UINT32) total_digits <= 34) {
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if (expon_diff >= 0) {
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T = power10_table_128[expon_diff];
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__mul_128x128_low (CX2, T, CX);
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get_BID128_very_fast (&res, sign_x, exponent_y, CX2);
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BID_RETURN (res);
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}
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#ifndef IEEE_ROUND_NEAREST_TIES_AWAY
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#ifndef IEEE_ROUND_NEAREST
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rmode = rnd_mode;
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if (sign_x && (unsigned) (rmode - 1) < 2)
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rmode = 3 - rmode;
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#else
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rmode = 0;
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#endif
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#else
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rmode = 0;
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#endif
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// must round off -expon_diff digits
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extra_digits = -expon_diff;
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__add_128_128 (CX, CX, round_const_table_128[rmode][extra_digits]);
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// get P*(2^M[extra_digits])/10^extra_digits
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__mul_128x128_to_256 (CT, CX, reciprocals10_128[extra_digits]);
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// now get P/10^extra_digits: shift C64 right by M[extra_digits]-128
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amount = recip_scale[extra_digits];
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CX2.w[0] = CT.w[2];
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CX2.w[1] = CT.w[3];
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if (amount >= 64) {
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CR.w[1] = 0;
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CR.w[0] = CX2.w[1] >> (amount - 64);
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} else {
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__shr_128 (CR, CX2, amount);
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}
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#ifndef IEEE_ROUND_NEAREST_TIES_AWAY
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#ifndef IEEE_ROUND_NEAREST
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if (rnd_mode == 0)
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#endif
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if (CR.w[0] & 1) {
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// check whether fractional part of initial_P/10^extra_digits is
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// exactly .5 this is the same as fractional part of
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// (initial_P + 0.5*10^extra_digits)/10^extra_digits is exactly zero
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// get remainder
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if (amount >= 64) {
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remainder_h = CX2.w[0] | (CX2.w[1] << (128 - amount));
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} else
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remainder_h = CX2.w[0] << (64 - amount);
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// test whether fractional part is 0
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if (!remainder_h
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&& (CT.w[1] < reciprocals10_128[extra_digits].w[1]
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|| (CT.w[1] == reciprocals10_128[extra_digits].w[1]
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&& CT.w[0] < reciprocals10_128[extra_digits].w[0]))) {
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CR.w[0]--;
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}
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}
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#endif
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#ifdef SET_STATUS_FLAGS
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status = INEXACT_EXCEPTION;
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// get remainder
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if (amount >= 64) {
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REM_H.w[1] = (CX2.w[1] << (128 - amount));
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REM_H.w[0] = CX2.w[0];
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} else {
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REM_H.w[1] = CX2.w[0] << (64 - amount);
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REM_H.w[0] = 0;
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}
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switch (rmode) {
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case ROUNDING_TO_NEAREST:
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case ROUNDING_TIES_AWAY:
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// test whether fractional part is 0
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if (REM_H.w[1] == 0x8000000000000000ull && !REM_H.w[0]
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&& (CT.w[1] < reciprocals10_128[extra_digits].w[1]
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|| (CT.w[1] == reciprocals10_128[extra_digits].w[1]
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&& CT.w[0] < reciprocals10_128[extra_digits].w[0])))
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status = EXACT_STATUS;
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break;
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case ROUNDING_DOWN:
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case ROUNDING_TO_ZERO:
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if (!(REM_H.w[1] | REM_H.w[0])
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&& (CT.w[1] < reciprocals10_128[extra_digits].w[1]
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|| (CT.w[1] == reciprocals10_128[extra_digits].w[1]
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&& CT.w[0] < reciprocals10_128[extra_digits].w[0])))
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status = EXACT_STATUS;
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break;
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default:
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// round up
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__add_carry_out (Stemp.w[0], CY64, CT.w[0],
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reciprocals10_128[extra_digits].w[0]);
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__add_carry_in_out (Stemp.w[1], carry, CT.w[1],
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reciprocals10_128[extra_digits].w[1], CY64);
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if (amount < 64) {
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C2N.w[1] = 0;
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C2N.w[0] = ((UINT64) 1) << amount;
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REM_H.w[0] = REM_H.w[1] >> (64 - amount);
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REM_H.w[1] = 0;
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} else {
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C2N.w[1] = ((UINT64) 1) << (amount - 64);
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C2N.w[0] = 0;
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REM_H.w[1] >>= (128 - amount);
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}
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REM_H.w[0] += carry;
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if (REM_H.w[0] < carry)
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REM_H.w[1]++;
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if (__unsigned_compare_ge_128 (REM_H, C2N))
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status = EXACT_STATUS;
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}
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__set_status_flags (pfpsf, status);
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#endif
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get_BID128_very_fast (&res, sign_x, exponent_y, CR);
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BID_RETURN (res);
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}
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if (total_digits < 0) {
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CR.w[1] = CR.w[0] = 0;
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#ifndef IEEE_ROUND_NEAREST_TIES_AWAY
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#ifndef IEEE_ROUND_NEAREST
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rmode = rnd_mode;
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if (sign_x && (unsigned) (rmode - 1) < 2)
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rmode = 3 - rmode;
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if (rmode == ROUNDING_UP)
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CR.w[0] = 1;
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#endif
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#endif
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#ifdef SET_STATUS_FLAGS
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__set_status_flags (pfpsf, INEXACT_EXCEPTION);
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#endif
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get_BID128_very_fast (&res, sign_x, exponent_y, CR);
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BID_RETURN (res);
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}
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// else more than 34 digits in coefficient
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#ifdef 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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