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SDL_systimer.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2006 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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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
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Lesser General Public License for more details.
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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
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Sam Lantinga
slouken@libsdl.org
*/
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#include "SDL_config.h"
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#ifdef SDL_TIMER_OS2
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#define INCL_DOSMISC
#define INCL_DOSERRORS
#define INCL_DOSSEMAPHORES
#define INCL_DOSDATETIME
#define INCL_DOSPROCESS
#define INCL_DOSPROFILE
#define INCL_DOSEXCEPTIONS
#include <os2.h>
#include "SDL_thread.h"
#include "SDL_timer.h"
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#include "../SDL_timer_c.h"
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#define TIME_WRAP_VALUE (~(DWORD)0)
/* The first high-resolution ticks value of the application */
static long long hires_start_ticks;
/* The number of ticks per second of the high-resolution performance counter */
static ULONG hires_ticks_per_second;
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void
SDL_StartTicks (void)
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{
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DosTmrQueryFreq (&hires_ticks_per_second);
DosTmrQueryTime ((PQWORD) & hires_start_ticks);
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}
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DECLSPEC Uint32 SDLCALL
SDL_GetTicks (void)
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{
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long long hires_now;
ULONG ticks = ticks;
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DosTmrQueryTime ((PQWORD) & hires_now);
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/*
hires_now -= hires_start_ticks;
hires_now *= 1000;
hires_now /= hires_ticks_per_second;
*/
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/* inline asm to avoid runtime inclusion */
_asm {
push edx
push eax
mov eax, dword ptr hires_now
mov edx, dword ptr hires_now + 4
sub eax, dword ptr hires_start_ticks
sbb edx, dword ptr hires_start_ticks + 4
mov ebx, 1000
mov ecx, edx
mul ebx
push eax
push edx
mov eax, ecx
mul ebx
pop eax
add edx, eax
pop eax
mov ebx, dword ptr hires_ticks_per_second
div ebx mov dword ptr ticks, eax pop edx pop eax}
return ticks;
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}
/* High resolution sleep, originally made by Ilya Zakharevich */
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DECLSPEC void SDLCALL
SDL_Delay (Uint32 ms)
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{
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/* This is similar to DosSleep(), but has 8ms granularity in time-critical
threads even on Warp3. */
HEV hevEvent1 = 0; /* Event semaphore handle */
HTIMER htimerEvent1 = 0; /* Timer handle */
APIRET rc = NO_ERROR; /* Return code */
int ret = 1;
ULONG priority = 0, nesting; /* Shut down the warnings */
PPIB pib;
PTIB tib;
char *e = NULL;
APIRET badrc;
int switch_priority = 50;
DosCreateEventSem (NULL, /* Unnamed */
&hevEvent1, /* Handle of semaphore returned */
DC_SEM_SHARED, /* Shared needed for DosAsyncTimer */
FALSE); /* Semaphore is in RESET state */
if (ms >= switch_priority)
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switch_priority = 0;
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if (switch_priority) {
if (DosGetInfoBlocks (&tib, &pib) != NO_ERROR)
switch_priority = 0;
else {
/* In Warp3, to switch scheduling to 8ms step, one needs to do
DosAsyncTimer() in time-critical thread. On laters versions,
more and more cases of wait-for-something are covered.
It turns out that on Warp3fp42 it is the priority at the time
of DosAsyncTimer() which matters. Let's hope that this works
with later versions too... XXXX
*/
priority = (tib->tib_ptib2->tib2_ulpri);
if ((priority & 0xFF00) == 0x0300) /* already time-critical */
switch_priority = 0;
/* Make us time-critical. Just modifying TIB is not enough... */
/* tib->tib_ptib2->tib2_ulpri = 0x0300; */
/* We do not want to run at high priority if a signal causes us
to longjmp() out of this section... */
if (DosEnterMustComplete (&nesting))
switch_priority = 0;
else
DosSetPriority (PRTYS_THREAD, PRTYC_TIMECRITICAL, 0, 0);
}
}
if ((badrc = DosAsyncTimer (ms, (HSEM) hevEvent1, /* Semaphore to post */
&htimerEvent1))) /* Timer handler (returned) */
e = "DosAsyncTimer";
if (switch_priority && tib->tib_ptib2->tib2_ulpri == 0x0300) {
/* Nobody switched priority while we slept... Ignore errors... */
/* tib->tib_ptib2->tib2_ulpri = priority; *//* Get back... */
if (!
(rc =
DosSetPriority (PRTYS_THREAD, (priority >> 8) & 0xFF, 0, 0)))
rc = DosSetPriority (PRTYS_THREAD, 0, priority & 0xFF, 0);
}
if (switch_priority)
rc = DosExitMustComplete (&nesting); /* Ignore errors */
/* The actual blocking call is made with "normal" priority. This way we
should not bother with DosSleep(0) etc. to compensate for us interrupting
higher-priority threads. The goal is to prohibit the system spending too
much time halt()ing, not to run us "no matter what". */
if (!e) /* Wait for AsyncTimer event */
badrc = DosWaitEventSem (hevEvent1, SEM_INDEFINITE_WAIT);
if (e); /* Do nothing */
else if (badrc == ERROR_INTERRUPT)
ret = 0;
else if (badrc)
e = "DosWaitEventSem";
if ((rc = DosCloseEventSem (hevEvent1)) && !e) { /* Get rid of semaphore */
e = "DosCloseEventSem";
badrc = rc;
}
if (e) {
SDL_SetError ("[SDL_Delay] : Had error in %s(), rc is 0x%x\n", e,
badrc);
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}
}
/* Data to handle a single periodic alarm */
static int timer_alive = 0;
static SDL_Thread *timer = NULL;
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static int
RunTimer (void *unused)
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{
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DosSetPriority (PRTYS_THREAD, PRTYC_TIMECRITICAL, 0, 0);
while (timer_alive) {
if (SDL_timer_running) {
SDL_ThreadedTimerCheck ();
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}
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SDL_Delay (10);
}
return (0);
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}
/* This is only called if the event thread is not running */
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int
SDL_SYS_TimerInit (void)
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{
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timer_alive = 1;
timer = SDL_CreateThread (RunTimer, NULL);
if (timer == NULL)
return (-1);
return (SDL_SetTimerThreaded (1));
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}
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void
SDL_SYS_TimerQuit (void)
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{
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timer_alive = 0;
if (timer) {
SDL_WaitThread (timer, NULL);
timer = NULL;
}
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}
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int
SDL_SYS_StartTimer (void)
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{
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SDL_SetError ("Internal logic error: OS/2 uses threaded timer");
return (-1);
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}
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void
SDL_SYS_StopTimer (void)
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{
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}
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#endif /* SDL_TIMER_OS2 */
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/* vi: set ts=4 sw=4 expandtab: */