1 /* Copyright (C) 2007, 2009 Free Software Foundation, Inc. 2 3 This file is part of GCC. 4 5 GCC is free software; you can redistribute it and/or modify it under 6 the terms of the GNU General Public License as published by the Free 7 Software Foundation; either version 3, or (at your option) any later 8 version. 9 10 GCC is distributed in the hope that it will be useful, but WITHOUT ANY 11 WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 for more details. 14 15 Under Section 7 of GPL version 3, you are granted additional 16 permissions described in the GCC Runtime Library Exception, version 17 3.1, as published by the Free Software Foundation. 18 19 You should have received a copy of the GNU General Public License and 20 a copy of the GCC Runtime Library Exception along with this program; 21 see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 22 <http://www.gnu.org/licenses/>. */ 23 24 #include "bid_internal.h" 25 26 #define MAX_FORMAT_DIGITS 16 27 #define DECIMAL_EXPONENT_BIAS 398 28 #define MAX_DECIMAL_EXPONENT 767 29 30 #if DECIMAL_CALL_BY_REFERENCE 31 32 void 33 bid64_scalb (UINT64 * pres, UINT64 * px, 34 int *pn _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM 35 _EXC_INFO_PARAM) { 36 UINT64 x; 37 int n; 38 #else 39 40 UINT64 41 bid64_scalb (UINT64 x, 42 int n _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM 43 _EXC_INFO_PARAM) { 44 #endif 45 UINT64 sign_x, coefficient_x, res; 46 SINT64 exp64; 47 int exponent_x, rmode; 48 49 #if DECIMAL_CALL_BY_REFERENCE 50 #if !DECIMAL_GLOBAL_ROUNDING 51 _IDEC_round rnd_mode = *prnd_mode; 52 #endif 53 x = *px; 54 n = *pn; 55 #endif 56 57 // unpack arguments, check for NaN or Infinity 58 if (!unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x)) { 59 // x is Inf. or NaN or 0 60 #ifdef SET_STATUS_FLAGS 61 if ((x & SNAN_MASK64) == SNAN_MASK64) // y is sNaN 62 __set_status_flags (pfpsf, INVALID_EXCEPTION); 63 #endif 64 if (coefficient_x) 65 res = coefficient_x & QUIET_MASK64; 66 else { 67 exp64 = (SINT64) exponent_x + (SINT64) n; 68 if(exp64<0) exp64=0; 69 if(exp64>MAX_DECIMAL_EXPONENT) exp64=MAX_DECIMAL_EXPONENT; 70 exponent_x = exp64; 71 res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x); // 0 72 } 73 BID_RETURN (res); 74 } 75 76 exp64 = (SINT64) exponent_x + (SINT64) n; 77 exponent_x = exp64; 78 79 if ((UINT32) exponent_x <= MAX_DECIMAL_EXPONENT) { 80 res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x); 81 BID_RETURN (res); 82 } 83 // check for overflow 84 if (exp64 > MAX_DECIMAL_EXPONENT) { 85 // try to normalize coefficient 86 while ((coefficient_x < 1000000000000000ull) 87 && (exp64 > MAX_DECIMAL_EXPONENT)) { 88 // coefficient_x < 10^15, scale by 10 89 coefficient_x = (coefficient_x << 1) + (coefficient_x << 3); 90 exponent_x--; 91 exp64--; 92 } 93 if (exp64 <= MAX_DECIMAL_EXPONENT) { 94 res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x); 95 BID_RETURN (res); 96 } else 97 exponent_x = 0x7fffffff; // overflow 98 } 99 // exponent < 0 100 // the BID pack routine will round the coefficient 101 rmode = rnd_mode; 102 res = get_BID64 (sign_x, exponent_x, coefficient_x, rmode, pfpsf); 103 BID_RETURN (res); 104 105 } 106