Fixed bug #15 SDL_blit_A.mmx-speed.patch.txt -- Speed improvements and a bugfix for the current GCC inline mmx asm code: - Changed some ops and removed some resulting useless ones. - Added some instruction parallelism (some gain) The resulting speed on my Xeon improved upto 35% depending on the function (measured in fps). - Fixed a bug where BlitRGBtoRGBSurfaceAlphaMMX() was setting the alpha component on the destination surfaces (to opaque-alpha) even when the surface had none. SDL_blit_A.mmx-msvc.patch.txt -- MSVC mmx intrinsics version of the same GCC asm code. MSVC compiler tries to parallelize the code and to avoid register stalls, but does not always do a very good job. Per-surface blending MSVC functions run quite a bit faster than their pure-asm counterparts (upto 55% faster for 16bit ones), but the per-pixel blending runs somewhat slower than asm. - BlitRGBtoRGBSurfaceAlphaMMX and BlitRGBtoRGBPixelAlphaMMX (and all variants) can now also handle formats other than (A)RGB8888. Formats like RGBA8888 and some quite exotic ones are allowed -- like RAGB8888, or actually anything having channels aligned on 8bit boundary and full 8bit alpha (for per-pixel alpha blending). The performance cost of this change is virtually 0 for per-surface alpha blending (no extra ops inside the loop) and a single non-MMX op inside the loop for per-pixel blending. In testing, the per-pixel alpha blending takes a ~2% performance hit, but it still runs much faster than the current code in CVS. If necessary, a separate function with this functionality can be made. This code requires Processor Pack for VC6.

.TH "SDL_CreateSemaphore" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_CreateSemaphore\- Creates a new semaphore and assigns an initial value to it\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
#include "SDL_thread\&.h"
.sp
\fBSDL_sem *\fBSDL_CreateSemaphore\fP\fR(\fBUint32 initial_value\fR);
.SH "DESCRIPTION"
.PP
\fBSDL_CreateSemaphore()\fP creates a new semaphore and initializes it with the value \fBinitial_value\fR\&. Each locking operation on the semaphore by \fISDL_SemWait\fR, \fISDL_SemTryWait\fR or \fISDL_SemWaitTimeout\fR will atomically decrement the semaphore value\&. The locking operation will be blocked if the semaphore value is not positive (greater than zero)\&. Each unlock operation by \fISDL_SemPost\fR will atomically increment the semaphore value\&.
.SH "RETURN VALUE"
.PP
Returns a pointer to an initialized semaphore or \fBNULL\fR if there was an error\&.
.SH "EXAMPLES"
.PP
.PP
.nf
\f(CWSDL_sem *my_sem;

my_sem = SDL_CreateSemaphore(INITIAL_SEM_VALUE);

if (my_sem == NULL) {
        return CREATE_SEM_FAILED;
}\fR
.fi
.PP
.SH "SEE ALSO"
.PP
\fI\fBSDL_DestroySemaphore\fP\fR, \fI\fBSDL_SemWait\fP\fR, \fI\fBSDL_SemTryWait\fP\fR, \fI\fBSDL_SemWaitTimeout\fP\fR, \fI\fBSDL_SemPost\fP\fR, \fI\fBSDL_SemValue\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00