Mercurial > sdl-ios-xcode
view TODO @ 2752:edd2839b36f7
http://sources.redhat.com/ml/newlib/2002/msg00230.html
Stephen L Moshier wrote:
>
> pow(x,y) returns 0 when x is very close to -1.0 and y is very large.
> The following test program prints
>
> pow(1.0000000000000002e+00 4.5035996273704970e+15) = 2.7182818284590455e+00
> pow(-1.0000000000000002e+00 4.5035996273704970e+15) =0.0000000000000000e+00
> pow(9.9999999999999978e-01 4.5035996273704970e+15) = 3.6787944117144222e-01
> pow(-9.9999999999999978e-01 4.5035996273704970e+15) = 0.0000000000000000e+00
>
> which is incorrect for the negative arguments raised to an odd integer
> power.
>
> -----
> double pow (double, double);
>
> int
> main ()
> {
> double x, y, z;
>
> x = 1.0 + pow (2.0, -52.0);
> y = 1.0 + pow (2.0, 52.0);
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = -x;
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = 1.0 - pow (2.0, -52.0);
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> x = -x;
> z = pow (x, y);
> printf ("pow(%.16e %.16e) = %.16e\n", x, y, z);
> }
> -----
>
> Here is a patch for newlib/libm/math/epow.c:
Patch checked in and duplicated for ef_pow.c. Thanks.
-- Jeff J.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Mon, 15 Sep 2008 04:31:30 +0000 |
| parents | 3458c74b5fab |
| children | 6f260584df22 |
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Wish list for the 1.3 development branch: http://bugzilla.libsdl.org/ * Add a way to register custom events * Add internal support for adding video modes and refresh rates * Support querying and setting refresh rate with video modes * Add mousewheel events (new unified event architecture?) * DirectInput joystick support needs to be implemented * Be able to enumerate and select available audio and video drivers * Fullscreen video mode support for Mac OS X * Explicit vertical retrace wait (maybe separate from SDL_Flip?) * Shaped windows, windows without borders * Multiple windows, multiple display support * SDL_INIT_EVENTTHREAD on Windows and MacOS? * Add a timestamp to events * Add audio input API * Add hardware accelerated scaled blit * Add hardware accelerated alpha blits * Redesign blitting architecture to allow blit plugins * Add modifier state to key and button events In the jump from 1.2 to 1.3, we should change the SDL_Rect members to int and evaluate all the rest of the datatypes. This is the only place we should do it though, since the 1.2 series should not break binary compatibility in this way. Requests: * PCM and CDROM volume control (deprecated, but possible)