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author | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
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committer | upstream source tree <ports@midipix.org> | 2015-03-15 20:14:05 -0400 |
commit | 554fd8c5195424bdbcabf5de30fdc183aba391bd (patch) | |
tree | 976dc5ab7fddf506dadce60ae936f43f58787092 /libgcc/config/libbid/bid64_scalb.c | |
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Diffstat (limited to 'libgcc/config/libbid/bid64_scalb.c')
-rw-r--r-- | libgcc/config/libbid/bid64_scalb.c | 105 |
1 files changed, 105 insertions, 0 deletions
diff --git a/libgcc/config/libbid/bid64_scalb.c b/libgcc/config/libbid/bid64_scalb.c new file mode 100644 index 000000000..a565d6598 --- /dev/null +++ b/libgcc/config/libbid/bid64_scalb.c @@ -0,0 +1,105 @@ +/* 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 +#define MAX_DECIMAL_EXPONENT 767 + +#if DECIMAL_CALL_BY_REFERENCE + +void +bid64_scalb (UINT64 * pres, UINT64 * px, + int *pn _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM + _EXC_INFO_PARAM) { + UINT64 x; + int n; +#else + +UINT64 +bid64_scalb (UINT64 x, + int n _RND_MODE_PARAM _EXC_FLAGS_PARAM _EXC_MASKS_PARAM + _EXC_INFO_PARAM) { +#endif + UINT64 sign_x, coefficient_x, res; + SINT64 exp64; + int exponent_x, rmode; + +#if DECIMAL_CALL_BY_REFERENCE +#if !DECIMAL_GLOBAL_ROUNDING + _IDEC_round rnd_mode = *prnd_mode; +#endif + x = *px; + n = *pn; +#endif + + // unpack arguments, check for NaN or Infinity + if (!unpack_BID64 (&sign_x, &exponent_x, &coefficient_x, x)) { + // x is Inf. or NaN or 0 +#ifdef SET_STATUS_FLAGS + if ((x & SNAN_MASK64) == SNAN_MASK64) // y is sNaN + __set_status_flags (pfpsf, INVALID_EXCEPTION); +#endif + if (coefficient_x) + res = coefficient_x & QUIET_MASK64; + else { + exp64 = (SINT64) exponent_x + (SINT64) n; + if(exp64<0) exp64=0; + if(exp64>MAX_DECIMAL_EXPONENT) exp64=MAX_DECIMAL_EXPONENT; + exponent_x = exp64; + res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x); // 0 + } + BID_RETURN (res); + } + + exp64 = (SINT64) exponent_x + (SINT64) n; + exponent_x = exp64; + + if ((UINT32) exponent_x <= MAX_DECIMAL_EXPONENT) { + res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x); + BID_RETURN (res); + } + // check for overflow + if (exp64 > MAX_DECIMAL_EXPONENT) { + // try to normalize coefficient + while ((coefficient_x < 1000000000000000ull) + && (exp64 > MAX_DECIMAL_EXPONENT)) { + // coefficient_x < 10^15, scale by 10 + coefficient_x = (coefficient_x << 1) + (coefficient_x << 3); + exponent_x--; + exp64--; + } + if (exp64 <= MAX_DECIMAL_EXPONENT) { + res = very_fast_get_BID64 (sign_x, exponent_x, coefficient_x); + BID_RETURN (res); + } else + exponent_x = 0x7fffffff; // overflow + } + // exponent < 0 + // the BID pack routine will round the coefficient + rmode = rnd_mode; + res = get_BID64 (sign_x, exponent_x, coefficient_x, rmode, pfpsf); + BID_RETURN (res); + +} |