Mercurial > sdl-ios-xcode
annotate docs/man3/SDL_SemWaitTimeout.3 @ 3899:081aecdb0911 SDL-1.2
From: Gabriel Gambetta
To: SDL Mailing List <sdl@libsdl.org>
Date: Fri, 17 Nov 2006 00:39:29 -0200
Subject: [SDL] Alpha blending bug - fixed?
It turns out mm5 never got the correct value. This failed :
[...]
"movd %1, %%mm5\n\t"
: : "m" (amask), "m" (sf->Ashift) );
mm5 got 0xFF000018 instead of 0x00000018. However I did this :
Uint32 ashift = sf->Ashift;
[...]
"movd %1, %%mm5\n\t"
: : "m" (amask), "m" (ashift) );
and everything worked fine.
The only thing I could find out was that ashift is 32-bit aligned but
sf->Ashift isn't:
printf("ashift %8X [%d]\n", &ashift, (int)(&ashift) % 4);
printf("sf->Ashift %8X [%d]\n", &sf->Ashift, (int)(&sf->Ashift) % 4);
ashift at BFF0E0C4 [0]
sf->Ashift at 08AFB9CD [1]
Could this be the problem? If it is, the fix is extremely trivial.
Should I submit a patch?
--Gabriel
| author | Ryan C. Gordon <icculus@icculus.org> |
|---|---|
| date | Tue, 21 Nov 2006 23:17:00 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
| rev | line source |
|---|---|
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
1 .TH "SDL_SemWaitTimeout" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" |
| 0 | 2 .SH "NAME" |
| 3 SDL_SemWaitTimeout\- Lock a semaphore, but only wait up to a specified maximum time\&. | |
| 4 .SH "SYNOPSIS" | |
| 5 .PP | |
| 6 \fB#include "SDL\&.h" | |
| 7 #include "SDL_thread\&.h" | |
| 8 .sp | |
| 9 \fBint \fBSDL_SemWaitTimeout\fP\fR(\fBSDL_sem *sem, Uint32 timeout\fR); | |
| 10 .SH "DESCRIPTION" | |
| 11 .PP | |
| 12 \fBSDL_SemWaitTimeout()\fP is a varient of \fISDL_SemWait\fR with a maximum timeout value\&. If the value of the semaphore pointed to by \fBsem\fR is positive (greater than zero) it will atomically decrement the semaphore value and return 0, otherwise it will wait up to \fBtimeout\fR milliseconds trying to lock the semaphore\&. This function is to be avoided if possible since on some platforms it is implemented by polling the semaphore every millisecond in a busy loop\&. | |
| 13 .PP | |
| 14 After \fBSDL_SemWaitTimeout()\fP is successful, the semaphore can be released and its count atomically incremented by a successful call to \fISDL_SemPost\fR\&. | |
| 15 .SH "RETURN VALUE" | |
| 16 .PP | |
| 17 Returns \fB0\fR if the semaphore was successfully locked or either \fBSDL_MUTEX_TIMEOUT\fR or \fB-1\fR if the timeout period was exceeded or there was an error, respectivly\&. | |
| 18 .PP | |
| 19 If the semaphore was not successfully locked, the semaphore will be unchanged\&. | |
| 20 .SH "EXAMPLES" | |
| 21 .PP | |
| 22 .PP | |
| 23 .nf | |
| 24 \f(CWres = SDL_SemWaitTimeout(my_sem, WAIT_TIMEOUT_MILLISEC); | |
| 25 | |
| 26 if (res == SDL_MUTEX_TIMEOUT) { | |
| 27 return TRY_AGAIN; | |
| 28 } | |
| 29 if (res == -1) { | |
| 30 return WAIT_ERROR; | |
| 31 } | |
| 32 | |
| 33 \&.\&.\&. | |
| 34 | |
| 35 SDL_SemPost(my_sem);\fR | |
| 36 .fi | |
| 37 .PP | |
| 38 .SH "SEE ALSO" | |
| 39 .PP | |
| 40 \fI\fBSDL_CreateSemaphore\fP\fR, \fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemWait\fP\fR, \fI\fBSDL_SemTryWait\fP\fR, \fI\fBSDL_SemPost\fP\fR, \fI\fBSDL_SemValue\fP\fR | |
|
181
e5bc29de3f0a
Updated from the SDL Documentation Project
Sam Lantinga <slouken@libsdl.org>
parents:
55
diff
changeset
|
41 ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00 |