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.

SDL on DirectFB

Supports:

- Hardware YUV overlays
- OpenGL - software only
- 2D/3D accelerations (depends on directfb driver)

What you need:

DirectFB 1.0.0 - required
Kernel-Framebuffer support: required: vesafb, radeonfb .... 
Mesa 7.0.x	   - optional for OpenGL

As of this writing 20070810 you need to pull Mesa from git and do the following:

------------------------
cd mesa 
make linux-directfb
make

echo Installing - pleaser enter sudo pw.

sudo make install INSTALL_DIR=/usr/local/dfb_GL
cd src/mesa/drivers/directfb
make
sudo make install INSTALL_DIR=/usr/local/dfb_GL
------------------------

To run the SDL - testprograms:

export SDL_VIDEODRIVER=directfb
export LD_LIBRARY_PATH=/usr/local/dfb_GL/lib
export LD_PRELOAD=/usr/local/dfb_GL/libGL.so.7

./testgl

To use hardware accelerated YUV-overlays for YUV-textures, use:

export SDL_DIRECTFB_YUV_DIRECT=1

This is disabled by default. It will only support one concurrent 
overlay and may behave strange if not used with SDL_CreateYUvOverlay
from SDLcompat.c.