Mercurial > sdl-ios-xcode
view include/SDL_timer.h @ 3162:dc1eb82ffdaa
Von: Thomas Zimmermann
Betreff: [SDL] [PATCH] Make static variables const
Datum: Tue, 19 May 2009 19:45:37 +0200
Hi,
this is a set of simple changes which make some of SDL's internal static
arrays constant. The purpose is to shrink the number of write-able
static bytes and thus increase the number of memory pages shared between
SDL applications.
The patch set is against trunk@4513. Each of the attached patch files is
specific to a sub-system. The set is completed by a second mail, because
of the list's 40 KiB limit.
The files readelf-r4513.txt and readelf-const-patch.txt where made by
calling 'readelf -S libSDL.so'. They show the difference in ELF sections
without and with the patch. Some numbers measured on my x86-64:
Before
[13] .rodata PROGBITS 00000000000eaaa0 000eaaa0
0000000000008170 0000000000000000 A 0 0 32
[19] .data.rel.ro PROGBITS 00000000003045e0 001045e0
00000000000023d0 0000000000000000 WA 0 0 32
[23] .data PROGBITS 00000000003076e0 001076e0
0000000000004988 0000000000000000 WA 0 0 32
After
[13] .rodata PROGBITS 00000000000eaaa0 000eaaa0
0000000000009a50 0000000000000000 A 0 0 32
[19] .data.rel.ro PROGBITS 0000000000306040 00106040
0000000000002608 0000000000000000 WA 0 0 32
[23] .data PROGBITS 0000000000309360 00109360
0000000000002e88 0000000000000000 WA 0 0 32
The size of the write-able data section decreased considerably. Some
entries became const-after-relocation, while most of its content went
straight into the read-only data section.
Best regards, Thomas
author | Sam Lantinga <slouken@libsdl.org> |
---|---|
date | Wed, 03 Jun 2009 04:37:27 +0000 |
parents | 99210400e8b9 |
children | d3baf5ac4e37 |
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/* SDL - Simple DirectMedia Layer Copyright (C) 1997-2009 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 */ #ifndef _SDL_timer_h #define _SDL_timer_h /** * \file SDL_timer.h * * Header for the SDL time management routines */ #include "SDL_stdinc.h" #include "SDL_error.h" #include "begin_code.h" /* Set up for C function definitions, even when using C++ */ #ifdef __cplusplus /* *INDENT-OFF* */ extern "C" { /* *INDENT-ON* */ #endif /* This is the OS scheduler timeslice, in milliseconds */ #define SDL_TIMESLICE 10 /* This is the maximum resolution of the SDL timer on all platforms */ #define TIMER_RESOLUTION 10 /* Experimentally determined */ /* Get the number of milliseconds since the SDL library initialization. * Note that this value wraps if the program runs for more than ~49 days. */ extern DECLSPEC Uint32 SDLCALL SDL_GetTicks(void); /* Wait a specified number of milliseconds before returning */ extern DECLSPEC void SDLCALL SDL_Delay(Uint32 ms); /* Function prototype for the timer callback function */ typedef Uint32(SDLCALL * SDL_TimerCallback) (Uint32 interval); /* Set a callback to run after the specified number of milliseconds has * elapsed. The callback function is passed the current timer interval * and returns the next timer interval. If the returned value is the * same as the one passed in, the periodic alarm continues, otherwise a * new alarm is scheduled. If the callback returns 0, the periodic alarm * is cancelled. * * To cancel a currently running timer, call SDL_SetTimer(0, NULL); * * The timer callback function may run in a different thread than your * main code, and so shouldn't call any functions from within itself. * * The maximum resolution of this timer is 10 ms, which means that if * you request a 16 ms timer, your callback will run approximately 20 ms * later on an unloaded system. If you wanted to set a flag signaling * a frame update at 30 frames per second (every 33 ms), you might set a * timer for 30 ms: * SDL_SetTimer((33/10)*10, flag_update); * * If you use this function, you need to pass SDL_INIT_TIMER to SDL_Init(). * * Under UNIX, you should not use raise or use SIGALRM and this function * in the same program, as it is implemented using setitimer(). You also * should not use this function in multi-threaded applications as signals * to multi-threaded apps have undefined behavior in some implementations. * * This function returns 0 if successful, or -1 if there was an error. */ extern DECLSPEC int SDLCALL SDL_SetTimer(Uint32 interval, SDL_TimerCallback callback); /* New timer API, supports multiple timers * Written by Stephane Peter <megastep@lokigames.com> */ /* Function prototype for the new timer callback function. * The callback function is passed the current timer interval and returns * the next timer interval. If the returned value is the same as the one * passed in, the periodic alarm continues, otherwise a new alarm is * scheduled. If the callback returns 0, the periodic alarm is cancelled. */ typedef Uint32(SDLCALL * SDL_NewTimerCallback) (Uint32 interval, void *param); /* Definition of the timer ID type */ typedef struct _SDL_TimerID *SDL_TimerID; /* Add a new timer to the pool of timers already running. Returns a timer ID, or NULL when an error occurs. */ extern DECLSPEC SDL_TimerID SDLCALL SDL_AddTimer(Uint32 interval, SDL_NewTimerCallback callback, void *param); /* Remove one of the multiple timers knowing its ID. * Returns a boolean value indicating success. */ extern DECLSPEC SDL_bool SDLCALL SDL_RemoveTimer(SDL_TimerID t); /* Ends C function definitions when using C++ */ #ifdef __cplusplus /* *INDENT-OFF* */ } /* *INDENT-ON* */ #endif #include "close_code.h" #endif /* _SDL_timer_h */ /* vi: set ts=4 sw=4 expandtab: */