Mercurial > sdl-ios-xcode
view src/video/xbios/SDL_xbios.h @ 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 | 2c835d58faad |
children | 99210400e8b9 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2006 Sam Lantinga This 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. This 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 this library; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA Sam Lantinga slouken@libsdl.org */ #include "SDL_config.h" #ifndef _SDL_xbios_h #define _SDL_xbios_h #include "SDL_stdinc.h" #include "../SDL_sysvideo.h" typedef struct SDL_VideoData { long cookie_vdo; /* _VDO cookie */ Uint16 old_modecode; /* Current video mode */ void *old_vbase; /* Current pointer to video RAM */ int old_numcol; /* Number of colors in saved palette */ Uint32 old_palette[256]; /* Buffer to save current palette */ #if 0 int old_video_mode; /* Old video mode before entering SDL */ void *old_video_base; /* Old pointer to screen buffer */ void *old_palette; /* Old palette */ Uint32 old_num_colors; /* Nb of colors in saved palette */ int num_modes; /* Number of xbios video modes */ xbiosmode_t *mode_list; /* List of xbios video modes */ void *screens[2]; /* Pointers to aligned screen buffer */ void *screensmem[2]; /* Pointers to screen buffer */ void *shadowscreen; /* Shadow screen for c2p conversion */ int doubleline; /* Double line mode ? */ int frame_number; /* Number of frame for double buffer */ int pitch; /* Destination line width for C2P */ int width, height; /* Screen size for centered C2P */ SDL_bool centscreen; /* Centscreen extension present ? */ SDL_Rect *SDL_modelist[NUM_MODELISTS][SDL_NUMMODES + 1]; xbiosmode_t *videomodes[NUM_MODELISTS][SDL_NUMMODES + 1]; #endif } SDL_VideoData; /* _VDO cookie values */ enum { VDO_ST = 0, VDO_STE, VDO_TT, VDO_F30 }; /* Monitor types */ enum { MONITOR_MONO = 0, MONITOR_TV, MONITOR_VGA, MONITOR_RGB }; /* EgetShift masks */ #define ES_BANK 0x000f #define ES_MODE 0x0700 #define ES_GRAY 0x1000 #define ES_SMEAR 0x8000 /* TT shifter modes */ #define ST_LOW 0x0000 #define ST_MED 0x0100 #define ST_HIGH 0x0200 #define TT_LOW 0x0700 #define TT_MED 0x0300 #define TT_HIGH 0x0600 #endif /* _SDL_xbios_h */ /* vi: set ts=4 sw=4 expandtab: */