diff options
Diffstat (limited to 'sysdeps')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c b/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c new file mode 100644 index 0000000000..011401ebca --- /dev/null +++ b/sysdeps/ieee754/dbl-64/wordsize-64/s_remquo.c @@ -0,0 +1,112 @@ +/* Compute remainder and a congruent to the quotient. + Copyright (C) 1997, 2011 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" + + +static const double zero = 0.0; + + +double +__remquo (double x, double y, int *quo) +{ + int64_t hx, hy; + uint64_t sx, qs; + int cquo; + + EXTRACT_WORDS64 (hx, x); + EXTRACT_WORDS64 (hy, y); + sx = hx & UINT64_C(0x8000000000000000); + qs = sx ^ (hy & UINT64_C(0x8000000000000000)); + hy &= UINT64_C(0x7fffffffffffffff); + hx &= UINT64_C(0x7fffffffffffffff); + + /* Purge off exception values. */ + if (__builtin_expect (hy == 0, 0)) + return (x * y) / (x * y); /* y = 0 */ + if (__builtin_expect (hx >= UINT64_C(0x7ff0000000000000) /* x not finite */ + || hy > UINT64_C(0x7ff0000000000000), 0))/* y is NaN */ + return (x * y) / (x * y); + + if (hy <= UINT64_C(0x7fbfffffffffffff)) + x = __ieee754_fmod (x, 8 * y); /* now x < 8y */ + + if (__builtin_expect (hx == hy, 0)) + { + *quo = qs ? -1 : 1; + return zero * x; + } + + INSERT_WORDS64 (x, hx); + INSERT_WORDS64 (y, hy); + cquo = 0; + + if (x >= 4 * y) + { + x -= 4 * y; + cquo += 4; + } + if (x >= 2 * y) + { + x -= 2 * y; + cquo += 2; + } + + if (hy < UINT64_C(0x0020000000000000)) + { + if (x + x > y) + { + x -= y; + ++cquo; + if (x + x >= y) + { + x -= y; + ++cquo; + } + } + } + else + { + double y_half = 0.5 * y; + if (x > y_half) + { + x -= y; + ++cquo; + if (x >= y_half) + { + x -= y; + ++cquo; + } + } + } + + *quo = qs ? -cquo : cquo; + + if (sx) + x = -x; + return x; +} +weak_alias (__remquo, remquo) +#ifdef NO_LONG_DOUBLE +strong_alias (__remquo, __remquol) +weak_alias (__remquo, remquol) +#endif |