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.

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 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"

/* 3Dfx register definitions */

#include "3dfx_regs.h"

/* 3Dfx control macros */

#define tdfx_in8(reg)		*(volatile Uint8  *)(mapped_io + (reg))
#define tdfx_in32(reg)		*(volatile Uint32 *)(mapped_io + (reg))

#define tdfx_out8(reg,v)	*(volatile Uint8  *)(mapped_io + (reg)) = v;
#define tdfx_out32(reg,v)	*(volatile Uint32 *)(mapped_io + (reg)) = v;


/* Wait for fifo space */
#define tdfx_wait(space)						\
{									\
	while ( (tdfx_in8(TDFX_STATUS) & 0x1F) < space )		\
		;							\
}


/* Wait for idle accelerator */
#define tdfx_waitidle()							\
{									\
	int i = 0;							\
									\
	tdfx_wait(1);							\
	tdfx_out32(COMMAND_3D, COMMAND_3D_NOP);				\
	do {								\
		i = (tdfx_in32(TDFX_STATUS) & STATUS_BUSY) ? 0 : i + 1;	\
	} while ( i != 3 );						\
}