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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/>. */
- #include "bid_internal.h"
- #define MAX_FORMAT_DIGITS 16
- #define DECIMAL_EXPONENT_BIAS 398
- #if DECIMAL_CALL_BY_REFERENCE
- void
- bid64_logb (int * pres, UINT64 * px
- _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
- UINT64 x;
- #else
- int
- bid64_logb (UINT64 x _EXC_FLAGS_PARAM _EXC_MASKS_PARAM _EXC_INFO_PARAM) {
- #endif
- UINT64 sign_x, coefficient_x;
- int_double dx;
- int exponent_x, bin_expon_cx, digits;
- #if DECIMAL_CALL_BY_REFERENCE
- x = *px;
- #endif
- // unpack arguments, check for NaN or Infinity
- if (!unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x)) {
- // x is Inf. or NaN
- #ifdef SET_STATUS_FLAGS
- __set_status_flags (pfpsf, INVALID_EXCEPTION);
- #endif
- BID_RETURN (0x80000000);
- }
- // find number of digits in coefficient
- if (coefficient_x >= 1000000000000000ull) {
- digits = 16;
- } else {
- dx.d = (double)coefficient_x; // exact conversion;
- bin_expon_cx = (int)(dx.i >> 52) - 1023;
- digits = estimate_decimal_digits[bin_expon_cx];
- if (coefficient_x >= power10_table_128[digits].w[0])
- digits++;
- }
- exponent_x = exponent_x - DECIMAL_EXPONENT_BIAS + digits - 1;
- BID_RETURN (exponent_x);
- }
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