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view src/video/xbios/SDL_xbios_sb3.c @ 2752:edd2839b36f7

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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 0e751c1f83f5
children 99210400e8b9
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/*
	ScreenBlaster 3 functions

	Patrice Mandin
*/

/*--- Includes ---*/

#include "SDL_stdinc.h"
#include "SDL_xbios.h"
#include "SDL_xbios_sb3.h"

/*--- Defines ---*/

const int SDL_XBIOS_scpn_planes_device[] = {
    SCPN_DEV_1BPP,
    SCPN_DEV_4BPP,
    SCPN_DEV_8BPP,
    SCPN_DEV_16BPP,
    SCPN_DEV_2BPP,
    SCPN_DEV_4BPP,
    SCPN_DEV_1BPP
};

/*--- Functions ---*/

int
SDL_XBIOS_SB3Usable(scpn_cookie_t * cookie_scpn)
{
#if 0
    scpn_screeninfo_t *scrinfo;
    int bpp;

    /* Check if current SB3 mode is usable, i.e. 8 or 16bpp */
    scrinfo = cookie_scpn->screen_info;
    bpp = 1 << (SDL_XBIOS_scpn_planes_device[scrinfo->device]);

    if ((bpp == 8) || (bpp == 16)) {
        return 1;
    }
#endif

    return 0;
}

void
SDL_XBIOS_SB3Init(_THIS, scpn_cookie_t * cookie_scpn)
{
#if 0
    scpn_screeninfo_t *scrinfo;

    /* SB3 prevent changing video modes, we can only use current one */
    if (XBIOS_modelist) {
        SDL_free(XBIOS_modelist);
        XBIOS_nummodes = 0;
        XBIOS_modelist = NULL;
    }

    scrinfo = cookie_scpn->screen_info;
    scrinfo->h_pos = scrinfo->v_pos = 0;

    SDL_XBIOS_AddMode(this,
                      -1,
                      scrinfo->virtual_width, scrinfo->virtual_height,
                      1 << (SDL_XBIOS_scpn_planes_device[scrinfo->device]),
                      SDL_FALSE);
#endif
}

/* vi: set ts=4 sw=4 expandtab: */