| /* Adapted for use as nearbyint by Ulrich Drepper <drepper@cygnus.com>. */ |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunPro, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| |
| /* |
| * rint(x) |
| * Return x rounded to integral value according to the prevailing |
| * rounding mode. |
| * Method: |
| * Using floating addition. |
| * Exception: |
| * Inexact flag raised if x not equal to rint(x). |
| */ |
| |
| #include <fenv.h> |
| #include <math.h> |
| #include <math_private.h> |
| |
| static const double |
| TWO52[2]={ |
| 4.50359962737049600000e+15, /* 0x43300000, 0x00000000 */ |
| -4.50359962737049600000e+15, /* 0xC3300000, 0x00000000 */ |
| }; |
| |
| double |
| __nearbyint(double x) |
| { |
| fenv_t env; |
| int64_t i0,sx; |
| int32_t j0; |
| EXTRACT_WORDS64(i0,x); |
| sx = (i0>>63)&1; |
| j0 = ((i0>>52)&0x7ff)-0x3ff; |
| if(__builtin_expect(j0<52, 1)) { |
| if(j0<0) { |
| libc_feholdexcept (&env); |
| double w = TWO52[sx]+x; |
| double t = w-TWO52[sx]; |
| math_opt_barrier(t); |
| libc_fesetenv (&env); |
| return copysign(t, x); |
| } |
| } else { |
| if(j0==0x400) return x+x; /* inf or NaN */ |
| else return x; /* x is integral */ |
| } |
| libc_feholdexcept (&env); |
| double w = TWO52[sx]+x; |
| double t = w-TWO52[sx]; |
| math_opt_barrier (t); |
| libc_fesetenv (&env); |
| return t; |
| } |
| weak_alias (__nearbyint, nearbyint) |
| #ifdef NO_LONG_DOUBLE |
| strong_alias (__nearbyint, __nearbyintl) |
| weak_alias (__nearbyint, nearbyintl) |
| #endif |
