view src/timer/nds/SDL_systimer.c @ 5113:481dabb098ef

Improved timer implementation The new timer model is formalized as using a separate thread to handle timer callbacks. This was the case on almost every platform before, but it's now a requirement, and simplifies the implementation and makes it perform consistently across platforms. Goals: * Minimize timer thread blocking * Dispatch timers as accurately as possible * SDL_AddTimer() and SDL_RemoveTimer() are completely threadsafe * SDL_RemoveTimer() doesn't crash with a timer that's expired or removed
author Sam Lantinga <slouken@libsdl.org>
date Thu, 27 Jan 2011 14:45:06 -0800
parents f7b03b6838cb
children b530ef003506
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2010 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"

#ifdef SDL_TIMER_NDS

#include <nds.h>
#include <nds/timers.h>

#include "SDL_timer.h"


static volatile Uint32 timer_ticks;

static void
NDS_TimerInterrupt(void)
{
    timer_ticks++;
}

void
SDL_StartTicks(void)
{
    timer_ticks = 0;

    TIMER_CR(3) = TIMER_DIV_1024 | TIMER_IRQ_REQ;
    TIMER_DATA(3) = TIMER_FREQ_1024(1000);
    irqSet(IRQ_TIMER3, NDS_TimerInterrupt);
    irqEnable(IRQ_TIMER3);
}

Uint32
SDL_GetTicks(void)
{
    return timer_ticks;
}

void
SDL_Delay(Uint32 ms)
{
    Uint32 start = SDL_GetTicks();
    while (timer_alive) {
        if ((SDL_GetTicks() - start) >= ms)
            break;
    }
}

#endif /* SDL_TIMER_NDS */

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