| /* origin: FreeBSD /usr/src/lib/msun/src/e_scalb.c */ |
| /* |
| * ==================================================== |
| * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. |
| * |
| * Developed at SunSoft, a Sun Microsystems, Inc. business. |
| * Permission to use, copy, modify, and distribute this |
| * software is freely granted, provided that this notice |
| * is preserved. |
| * ==================================================== |
| */ |
| /* |
| * scalb(x, fn) is provide for |
| * passing various standard test suite. One |
| * should use scalbn() instead. |
| */ |
| |
| #define _GNU_SOURCE |
| #include <math.h> |
| |
| double scalb(double x, double fn) { |
| if (isnan(x) || isnan(fn)) |
| return x * fn; |
| if (!isfinite(fn)) { |
| if (fn > 0.0) |
| return x * fn; |
| else |
| return x / (-fn); |
| } |
| if (rint(fn) != fn) |
| return (fn - fn) / (fn - fn); |
| if (fn > 65000.0) |
| return scalbn(x, 65000); |
| if (-fn > 65000.0) |
| return scalbn(x, -65000); |
| return scalbn(x, (int)fn); |
| } |
