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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/bid128_logb.c | |
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Diffstat (limited to 'libgcc/config/libbid/bid128_logb.c')
-rw-r--r-- | libgcc/config/libbid/bid128_logb.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/libgcc/config/libbid/bid128_logb.c b/libgcc/config/libbid/bid128_logb.c new file mode 100644 index 000000000..f462cf6a6 --- /dev/null +++ b/libgcc/config/libbid/bid128_logb.c @@ -0,0 +1,58 @@ +/* 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/>. */ + +#define BID_128RES +#include "bid_internal.h" + +BID128_FUNCTION_ARG1_NORND_CUSTOMRESTYPE(int, bid128_logb, x) + + UINT128 CX; + UINT64 sign_x; + SINT64 D; + int_float f64, fx; + int exponent_x, bin_expon_cx, digits; + + if (!unpack_BID128_value (&sign_x, &exponent_x, &CX, x)) { +#ifdef SET_STATUS_FLAGS + __set_status_flags (pfpsf, INVALID_EXCEPTION); +#endif + BID_RETURN_VAL (0x80000000); + } + // find number of digits in coefficient + // 2^64 + f64.i = 0x5f800000; + // fx ~ CX + fx.d = (float) CX.w[1] * f64.d + (float) CX.w[0]; + bin_expon_cx = ((fx.i >> 23) & 0xff) - 0x7f; + digits = estimate_decimal_digits[bin_expon_cx]; + // scale = 38-estimate_decimal_digits[bin_expon_cx]; + D = CX.w[1] - power10_index_binexp_128[bin_expon_cx].w[1]; + if (D > 0 || (!D && CX.w[0] >= power10_index_binexp_128[bin_expon_cx].w[0])) { + digits++; + } + + exponent_x = exponent_x - DECIMAL_EXPONENT_BIAS_128 - 1 + digits; + + BID_RETURN_VAL (exponent_x); + +} |