diff options
author | Mike Frysinger <vapier@gentoo.org> | 2005-11-03 23:57:25 +0000 |
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committer | Mike Frysinger <vapier@gentoo.org> | 2005-11-03 23:57:25 +0000 |
commit | ea8e9b58cc284de51f163abf762c0504880a4041 (patch) | |
tree | f296281888098f7a6bed1eb0dfe46424c6535847 /libm/s_lround.c | |
parent | abc27c85d619d917d411080a24373f98fe5d88ac (diff) |
add implementations from glibc for the round functions
Diffstat (limited to 'libm/s_lround.c')
-rw-r--r-- | libm/s_lround.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/libm/s_lround.c b/libm/s_lround.c new file mode 100644 index 000000000..5b1d5467e --- /dev/null +++ b/libm/s_lround.c @@ -0,0 +1,75 @@ +/* Round double value to long int. + Copyright (C) 1997, 2004 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@cygnus.com>, 1997. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library 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 + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <math.h> + +#include "math_private.h" + + +long int +lround (double x) +{ + int32_t j0; + u_int32_t i1, i0; + long int result; + int sign; + + EXTRACT_WORDS (i0, i1, x); + j0 = ((i0 >> 20) & 0x7ff) - 0x3ff; + sign = (i0 & 0x80000000) != 0 ? -1 : 1; + i0 &= 0xfffff; + i0 |= 0x100000; + + if (j0 < 20) + { + if (j0 < 0) + return j0 < -1 ? 0 : sign; + else + { + i0 += 0x80000 >> j0; + + result = i0 >> (20 - j0); + } + } + else if (j0 < (int32_t) (8 * sizeof (long int)) - 1) + { + if (j0 >= 52) + result = ((long int) i0 << (j0 - 20)) | (i1 << (j0 - 52)); + else + { + u_int32_t j = i1 + (0x80000000 >> (j0 - 20)); + if (j < i1) + ++i0; + + if (j0 == 20) + result = (long int) i0; + else + result = ((long int) i0 << (j0 - 20)) | (j >> (52 - j0)); + } + } + else + { + /* The number is too large. It is left implementation defined + what happens. */ + return (long int) x; + } + + return sign * result; +} |