Mercurial > sdl-ios-xcode
view src/cdrom/SDL_syscdrom.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 | 542c78b6fb12 |
children | 99210400e8b9 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2006 Sam Lantinga This library is SDL_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" /* This is the system specific header for the SDL CD-ROM API */ /* Structure of CD audio control functions */ extern struct CDcaps { /* Get the name of the specified drive */ const char *(*Name) (int drive); /* Open the specified drive, returning a drive id, or -1 on error */ int (*Open) (int drive); /* Get table-of-contents (number of tracks + track info) for disk. The TOC information should be stored in the cdrom structure. This function should return 0 on success, or -1 on error. */ int (*GetTOC) (SDL_CD * cdrom); /* Return the current status and play position, in frames, of the drive. 'position' may be NULL, and if so, should be ignored. */ CDstatus(*Status) (SDL_CD * cdrom, int *position); /* Play from frame 'start' to 'start+len' */ int (*Play) (SDL_CD * cdrom, int start, int len); /* Pause play */ int (*Pause) (SDL_CD * cdrom); /* Resume play */ int (*Resume) (SDL_CD * cdrom); /* Stop play */ int (*Stop) (SDL_CD * cdrom); /* Eject the current disk */ int (*Eject) (SDL_CD * cdrom); /* Close the specified drive */ void (*Close) (SDL_CD * cdrom); } SDL_CDcaps; /* The number of available CD-ROM drives on the system */ extern int SDL_numcds; /* Function to scan the system for CD-ROM drives and fill SDL_CDcaps. * This function should set SDL_numcds to the number of available CD * drives. Drive 0 should be the system default CD-ROM. * It should return 0, or -1 on an unrecoverable fatal error. */ extern int SDL_SYS_CDInit(void); /* Function to perform any system-specific CD-ROM related cleanup */ extern void SDL_SYS_CDQuit(void); /* vi: set ts=4 sw=4 expandtab: */