| /* Copyright (C) 2007, 2009 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); |
| } |