view src/video/SDL_blit_A.c @ 934:af585d6efec8

Date: Thu, 17 Jun 2004 11:38:51 -0700 (PDT) From: Eric Wing <ewing2121@yahoo.com> Subject: New OS X patch (was Re: [SDL] Bug with inverted mouse coordinates in I have a new patch for OS X I would like to submit. First, it appears no further action has been taken on my fix from Apple on the OpenGL windowed mode mouse inversion problem. The fix would reunify the code, and no longer require case checking for which version of the OS you are running. This is probably a good fix because the behavior with the old code could change again with future versions of the OS, so those fixes are included in this new patch. But in addition, when I was at Apple, I asked them about the ability to distinguish between the modifier keys on the left and right sides of the keyboard (e.g. Left Shift, Right Shift, Left/Right Alt, L/R Cmd, L/R Ctrl). They told me that starting with Panther, the OS began supporting this feature. This has always been a source of annoyance for me when bringing a program that comes from Windows or Linux to OS X when the keybindings happened to need distinguishable left-side and right-side keys. So the rest of the patch I am submitting contains new code to support this feature on Panther (and presumably later versions of the OS). So after removing the OS version checks for the mouse inversion problem, I reused the OS version checks to activate the Left/Right detection of modifier keys. If you are running Panther (or above), the new code will attempt to distinguish between sides. For the older OS's, the code path reverts to the original code. I've tested with Panther on a G4 Cube, G5 dual processor, and Powerbook Rev C. The Cube and G5 keyboards demonstrated the ability to distinguish between sides. The Powerbook seems to only have left-side keys, but the patch was still able to handle it by producing the same results as before the patch. I also wanted to test a non-Apple keyboard. Unfortunately, I don't have any PC USB keyboards. However, I was able to borrow a Sun Microsystems USB keyboard, so I tried that out on the G5, and I got the correct behavior for left and right sides. I'm expecting that if it worked with a Sun keyboard, most other keyboards should work with no problems.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 20 Aug 2004 22:35:23 +0000
parents 9ef41050100c
children ffaaf7ecf685
line wrap: on
line source

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2004 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 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
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

#ifdef SAVE_RCSID
static char rcsid =
 "@(#) $Id$";
#endif

#include <stdio.h>

#include "SDL_types.h"
#include "SDL_video.h"
#include "SDL_blit.h"

#if (defined(i386) || defined(__x86_64__)) && defined(__GNUC__) && defined(USE_ASMBLIT)
#define MMX_ASMBLIT
#endif

#ifdef MMX_ASMBLIT
/* Function to check the CPU flags */
#include "SDL_cpuinfo.h"
#include "mmx.h"
#endif

/* Functions to perform alpha blended blitting */

/* N->1 blending with per-surface alpha */
static void BlitNto1SurfaceAlpha(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint8 *src = info->s_pixels;
	int srcskip = info->s_skip;
	Uint8 *dst = info->d_pixels;
	int dstskip = info->d_skip;
	Uint8 *palmap = info->table;
	SDL_PixelFormat *srcfmt = info->src;
	SDL_PixelFormat *dstfmt = info->dst;
	int srcbpp = srcfmt->BytesPerPixel;

	const unsigned A = srcfmt->alpha;

	while ( height-- ) {
	    DUFFS_LOOP4(
	    {
		Uint32 pixel;
		unsigned sR;
		unsigned sG;
		unsigned sB;
		unsigned dR;
		unsigned dG;
		unsigned dB;
		DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
		dR = dstfmt->palette->colors[*dst].r;
		dG = dstfmt->palette->colors[*dst].g;
		dB = dstfmt->palette->colors[*dst].b;
		ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);
		dR &= 0xff;
		dG &= 0xff;
		dB &= 0xff;
		/* Pack RGB into 8bit pixel */
		if ( palmap == NULL ) {
		    *dst =((dR>>5)<<(3+2))|
			  ((dG>>5)<<(2))|
			  ((dB>>6)<<(0));
		} else {
		    *dst = palmap[((dR>>5)<<(3+2))|
				  ((dG>>5)<<(2))  |
				  ((dB>>6)<<(0))];
		}
		dst++;
		src += srcbpp;
	    },
	    width);
	    src += srcskip;
	    dst += dstskip;
	}
}

/* N->1 blending with pixel alpha */
static void BlitNto1PixelAlpha(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint8 *src = info->s_pixels;
	int srcskip = info->s_skip;
	Uint8 *dst = info->d_pixels;
	int dstskip = info->d_skip;
	Uint8 *palmap = info->table;
	SDL_PixelFormat *srcfmt = info->src;
	SDL_PixelFormat *dstfmt = info->dst;
	int srcbpp = srcfmt->BytesPerPixel;

	/* FIXME: fix alpha bit field expansion here too? */
	while ( height-- ) {
	    DUFFS_LOOP4(
	    {
		Uint32 pixel;
		unsigned sR;
		unsigned sG;
		unsigned sB;
		unsigned sA;
		unsigned dR;
		unsigned dG;
		unsigned dB;
		DISEMBLE_RGBA(src,srcbpp,srcfmt,pixel,sR,sG,sB,sA);
		dR = dstfmt->palette->colors[*dst].r;
		dG = dstfmt->palette->colors[*dst].g;
		dB = dstfmt->palette->colors[*dst].b;
		ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
		dR &= 0xff;
		dG &= 0xff;
		dB &= 0xff;
		/* Pack RGB into 8bit pixel */
		if ( palmap == NULL ) {
		    *dst =((dR>>5)<<(3+2))|
			  ((dG>>5)<<(2))|
			  ((dB>>6)<<(0));
		} else {
		    *dst = palmap[((dR>>5)<<(3+2))|
				  ((dG>>5)<<(2))  |
				  ((dB>>6)<<(0))  ];
		}
		dst++;
		src += srcbpp;
	    },
	    width);
	    src += srcskip;
	    dst += dstskip;
	}
}

/* colorkeyed N->1 blending with per-surface alpha */
static void BlitNto1SurfaceAlphaKey(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint8 *src = info->s_pixels;
	int srcskip = info->s_skip;
	Uint8 *dst = info->d_pixels;
	int dstskip = info->d_skip;
	Uint8 *palmap = info->table;
	SDL_PixelFormat *srcfmt = info->src;
	SDL_PixelFormat *dstfmt = info->dst;
	int srcbpp = srcfmt->BytesPerPixel;
	Uint32 ckey = srcfmt->colorkey;

	const int A = srcfmt->alpha;

	while ( height-- ) {
	    DUFFS_LOOP(
	    {
		Uint32 pixel;
		unsigned sR;
		unsigned sG;
		unsigned sB;
		unsigned dR;
		unsigned dG;
		unsigned dB;
		DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
		if ( pixel != ckey ) {
		    dR = dstfmt->palette->colors[*dst].r;
		    dG = dstfmt->palette->colors[*dst].g;
		    dB = dstfmt->palette->colors[*dst].b;
		    ALPHA_BLEND(sR, sG, sB, A, dR, dG, dB);
		    dR &= 0xff;
		    dG &= 0xff;
		    dB &= 0xff;
		    /* Pack RGB into 8bit pixel */
		    if ( palmap == NULL ) {
			*dst =((dR>>5)<<(3+2))|
			      ((dG>>5)<<(2)) |
			      ((dB>>6)<<(0));
		    } else {
			*dst = palmap[((dR>>5)<<(3+2))|
				      ((dG>>5)<<(2))  |
				      ((dB>>6)<<(0))  ];
		    }
		}
		dst++;
		src += srcbpp;
	    },
	    width);
	    src += srcskip;
	    dst += dstskip;
	}
}

#ifdef MMX_ASMBLIT
/* fast RGB888->(A)RGB888 blending with surface alpha=128 special case */
static void BlitRGBtoRGBSurfaceAlpha128MMX(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint32 *srcp = (Uint32 *)info->s_pixels;
	int srcskip = info->s_skip >> 2;
	Uint32 *dstp = (Uint32 *)info->d_pixels;
	int dstskip = info->d_skip >> 2;
        Uint8 load[8];
  
        *(Uint64 *)load = 0x00fefefe00fefefeULL;/* alpha128 mask */
        movq_m2r(*load, mm4); /* alpha128 mask -> mm4 */
        *(Uint64 *)load = 0x0001010100010101ULL;/* !alpha128 mask */
        movq_m2r(*load, mm3); /* !alpha128 mask -> mm3 */
        *(Uint64 *)load = 0xFF000000FF000000ULL;/* dst alpha mask */
        movq_m2r(*load, mm7); /* dst alpha mask -> mm7 */
	while(height--) {
            DUFFS_LOOP_DOUBLE2(
            {
		    Uint32 s = *srcp++;
		    Uint32 d = *dstp;
		    *dstp++ = ((((s & 0x00fefefe) + (d & 0x00fefefe)) >> 1)
			       + (s & d & 0x00010101)) | 0xff000000;
            },{
	            movq_m2r((*dstp), mm2);/* 2 x dst -> mm2(ARGBARGB) */
	            movq_r2r(mm2, mm6); /* 2 x dst -> mm6(ARGBARGB) */
	      
	            movq_m2r((*srcp), mm1);/* 2 x src -> mm1(ARGBARGB) */
	            movq_r2r(mm1, mm5); /* 2 x src -> mm5(ARGBARGB) */
		
	            pand_r2r(mm4, mm6); /* dst & mask -> mm6 */
	            pand_r2r(mm4, mm5); /* src & mask -> mm5 */
	            paddd_r2r(mm6, mm5); /* mm6 + mm5 -> mm5 */
	            psrld_i2r(1, mm5); /* mm5 >> 1 -> mm5 */
	
	            pand_r2r(mm1, mm2); /* src & dst -> mm2 */
	            pand_r2r(mm3, mm2); /* mm2 & !mask -> mm2 */
	            paddd_r2r(mm5, mm2); /* mm5 + mm2 -> mm2 */
	            por_r2r(mm7, mm2); /* mm7(full alpha) | mm2 -> mm2 */
	            movq_r2m(mm2, (*dstp));/* mm2 -> 2 x dst pixels */
	            dstp += 2;
	            srcp += 2;
            }, width);
	    srcp += srcskip;
	    dstp += dstskip;
	}
	emms();
}

/* fast RGB888->(A)RGB888 blending with surface alpha */
static void BlitRGBtoRGBSurfaceAlphaMMX(SDL_BlitInfo *info)
{
	unsigned alpha = info->src->alpha;
	if(alpha == 128) {
		BlitRGBtoRGBSurfaceAlpha128MMX(info);
	} else {
		int width = info->d_width;
		int height = info->d_height;
		Uint32 *srcp = (Uint32 *)info->s_pixels;
		int srcskip = info->s_skip >> 2;
		Uint32 *dstp = (Uint32 *)info->d_pixels;
		int dstskip = info->d_skip >> 2;
                Uint8 load[8] = {alpha, alpha, alpha, alpha,
    					alpha, alpha, alpha, alpha};
					
                movq_m2r(*load, mm4); /* alpha -> mm4 */
		*(Uint64 *)load = 0x00FF00FF00FF00FFULL;
                movq_m2r(*load, mm3); /* mask -> mm3 */
		pand_r2r(mm3, mm4); /* mm4 & mask -> 0A0A0A0A -> mm4 */
		*(Uint64 *)load = 0xFF000000FF000000ULL;/* dst alpha mask */
		movq_m2r(*load, mm7); /* dst alpha mask -> mm7 */
		
		while(height--) {
			DUFFS_LOOP_DOUBLE2({
				/* One Pixel Blend */
	                        movd_m2r((*srcp), mm1);/* src(ARGB) -> mm1 (0000ARGB)*/
                                punpcklbw_r2r(mm1, mm1); /* AARRGGBB -> mm1 */
                                pand_r2r(mm3, mm1); /* 0A0R0G0B -> mm1 */
			  
	                        movd_m2r((*dstp), mm2);/* dst(ARGB) -> mm2 (0000ARGB)*/
			        movq_r2r(mm2, mm6);/* dst(ARGB) -> mm6 (0000ARGB)*/
                                punpcklbw_r2r(mm2, mm2); /* AARRGGBB -> mm2 */
                                pand_r2r(mm3, mm2); /* 0A0R0G0B -> mm2 */
			  
                                psubw_r2r(mm2, mm1);/* src - dst -> mm1 */
	                        pmullw_r2r(mm4, mm1); /* mm1 * alpha -> mm1 */
	                        psrlw_i2r(8, mm1); /* mm1 >> 8 -> mm1 */
	                        paddw_r2r(mm1, mm2); /* mm1 + mm2(dst) -> mm2 */
	                        pand_r2r(mm3, mm2); /* 0A0R0G0B -> mm2 */
	                        packuswb_r2r(mm2, mm2);  /* ARGBARGB -> mm2 */
	                        por_r2r(mm7, mm2); /* mm7(full alpha) | mm2 -> mm2 */
			        movd_r2m(mm2, *dstp);/* mm2 -> pixel */
				++srcp;
				++dstp;
			},{
			        /* Two Pixels Blend */
				movq_m2r((*srcp), mm0);/* 2 x src -> mm0(ARGBARGB)*/
			        movq_r2r(mm0, mm1); /* 2 x src -> mm1(ARGBARGB) */
                                punpcklbw_r2r(mm0, mm0); /* low - AARRGGBB -> mm0 */
			        pand_r2r(mm3, mm0); /* 0A0R0G0B -> mm0(src1) */
			        punpckhbw_r2r(mm1, mm1); /* high - AARRGGBB -> mm1 */
	                        pand_r2r(mm3, mm1); /* 0A0R0G0B -> mm1(src2) */
	
	                        movq_m2r((*dstp), mm2);/* 2 x dst -> mm2(ARGBARGB) */
	                        movq_r2r(mm2, mm5); /* 2 x dst -> mm5(ARGBARGB) */
			        movq_r2r(mm2, mm6); /* 2 x dst -> mm6(ARGBARGB) */
                                punpcklbw_r2r(mm2, mm2); /* low - AARRGGBB -> mm2 */
	                        punpckhbw_r2r(mm6, mm6); /* high - AARRGGBB -> mm6 */
                                pand_r2r(mm3, mm2); /* 0A0R0G0B -> mm2(dst1) */
	                  
                                psubw_r2r(mm2, mm0);/* src1 - dst1 -> mm0 */
	                        pmullw_r2r(mm4, mm0); /* mm0 * alpha -> mm0 */
			        pand_r2r(mm3, mm6); /* 0A0R0G0B -> mm6(dst2) */
			        psrlw_i2r(8, mm0); /* mm0 >> 8 -> mm1 */
			        psubw_r2r(mm6, mm1);/* src2 - dst2 -> mm1 */
	                        pmullw_r2r(mm4, mm1); /* mm1 * alpha -> mm1 */
				paddw_r2r(mm0, mm2); /* mm0 + mm2(dst1) -> mm2 */
	                        psrlw_i2r(8, mm1); /* mm1 >> 8 -> mm0 */
				pand_r2r(mm3, mm2); /* 0A0R0G0B -> mm2 */
	                        paddw_r2r(mm1, mm6); /* mm1 + mm6(dst2) -> mm6 */
	                        pand_r2r(mm3, mm6); /* 0A0R0G0B -> mm6 */
	                        packuswb_r2r(mm2, mm2);  /* ARGBARGB -> mm2 */
	                        packuswb_r2r(mm6, mm6);  /* ARGBARGB -> mm6 */
	                        psrlq_i2r(32, mm2); /* mm2 >> 32 -> mm2 */
	                        psllq_i2r(32, mm6); /* mm6 << 32 -> mm6 */
	                        por_r2r(mm6, mm2); /* mm6 | mm2 -> mm2 */				
				por_r2r(mm7, mm2); /* mm7(full alpha) | mm2 -> mm2 */
                                movq_r2m(mm2, *dstp);/* mm2 -> 2 x pixel */
				srcp += 2;
				dstp += 2;
			}, width);
			srcp += srcskip;
			dstp += dstskip;
		}
		emms();
	}
}

/* fast ARGB888->(A)RGB888 blending with pixel alpha */
static void BlitRGBtoRGBPixelAlphaMMX(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint32 *srcp = (Uint32 *)info->s_pixels;
	int srcskip = info->s_skip >> 2;
	Uint32 *dstp = (Uint32 *)info->d_pixels;
	int dstskip = info->d_skip >> 2;
        Uint32 alpha = 0;
        Uint8 load[8];
	                
	*(Uint64 *)load = 0x00FF00FF00FF00FFULL;
        movq_m2r(*load, mm3); /* mask -> mm2 */
	*(Uint64 *)load = 0x00FF000000000000ULL;
        movq_m2r(*load, mm7); /* dst alpha mask -> mm2 */
        *(Uint64 *)load = 0x00FFFFFF00FFFFFFULL;
        movq_m2r(*load, mm0); /* alpha 255 mask -> mm0 */
        *(Uint64 *)load = 0xFF000000FF000000ULL;
        movq_m2r(*load, mm6); /* alpha 255 !mask -> mm6 */
	while(height--) {
	    DUFFS_LOOP4({
	        alpha = *srcp;
	        alpha >>= 24;
		/* FIXME: Here we special-case opaque alpha since the
		   compositioning used (>>8 instead of /255) doesn't handle
		   it correctly. Also special-case alpha=0 for speed?
		   Benchmark this! */
		if(alpha) {   
		  if(alpha == SDL_ALPHA_OPAQUE) {
		    movd_m2r((*srcp), mm1);/* src(ARGB) -> mm1 (0000ARGB)*/
		    movd_m2r((*dstp), mm2);/* dst(ARGB) -> mm2 (0000ARGB)*/
		    pand_r2r(mm0, mm1);
		    pand_r2r(mm6, mm2);
		    por_r2r(mm1, mm2);
		    movd_r2m(mm2, (*dstp));
		  } else {
		    movd_m2r((*srcp), mm1);/* src(ARGB) -> mm1 (0000ARGB)*/
                    punpcklbw_r2r(mm1, mm1); /* AARRGGBB -> mm1 */
                    pand_r2r(mm3, mm1); /* 0A0R0G0B -> mm1 */
			  
	            movd_m2r((*dstp), mm2);/* dst(ARGB) -> mm2 (0000ARGB)*/
                    punpcklbw_r2r(mm2, mm2); /* AARRGGBB -> mm2 */
                    pand_r2r(mm3, mm2); /* 0A0R0G0B -> mm2 */
		
		    movq_r2r(mm2, mm5);/* mm2(0A0R0G0B) -> mm5 */
		    pand_r2r(mm7, mm5); /* mm5 & dst alpha mask -> mm5(0A000000) */
		    psrlq_i2r(24, mm5); /* mm5 >> 24 -> mm5 (0000A000)*/
		    
		    movq_r2r(mm1, mm4);/* mm1(0A0R0G0B) -> mm4 */
		    psrlq_i2r(48, mm4); /* mm4 >> 48 -> mm4(0000000A) */
		    punpcklwd_r2r(mm4, mm4); /* 00000A0A -> mm4 */
                    punpcklwd_r2r(mm4, mm4); /* 0A0A0A0A -> mm4 */
		                        		    
                    /* blend */		    
                    psubw_r2r(mm2, mm1);/* src - dst -> mm1 */
	            pmullw_r2r(mm4, mm1); /* mm1 * alpha -> mm1 */
	            psrlw_i2r(8, mm1); /* mm1 >> 8 -> mm1 */
	            paddw_r2r(mm1, mm2); /* mm1 + mm2(dst) -> mm2 */
	            pand_r2r(mm3, mm2); /* 0A0R0G0B -> mm2 */
		    packuswb_r2r(mm2, mm2);  /* ARGBARGB -> mm2 */
		    pand_r2r(mm0, mm2); /* 0RGB0RGB -> mm2 */
		    por_r2r(mm5, mm2); /* dst alpha | mm2 -> mm2 */
		    movd_r2m(mm2, *dstp);/* mm2 -> dst */
		  }
		}
		++srcp;
		++dstp;
	    }, width);
	    srcp += srcskip;
	    dstp += dstskip;
	}
	emms();
}
#endif

/* fast RGB888->(A)RGB888 blending with surface alpha=128 special case */
static void BlitRGBtoRGBSurfaceAlpha128(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint32 *srcp = (Uint32 *)info->s_pixels;
	int srcskip = info->s_skip >> 2;
	Uint32 *dstp = (Uint32 *)info->d_pixels;
	int dstskip = info->d_skip >> 2;

	while(height--) {
	    DUFFS_LOOP4({
		    Uint32 s = *srcp++;
		    Uint32 d = *dstp;
		    *dstp++ = ((((s & 0x00fefefe) + (d & 0x00fefefe)) >> 1)
			       + (s & d & 0x00010101)) | 0xff000000;
	    }, width);
	    srcp += srcskip;
	    dstp += dstskip;
	}
}

/* fast RGB888->(A)RGB888 blending with surface alpha */
static void BlitRGBtoRGBSurfaceAlpha(SDL_BlitInfo *info)
{
	unsigned alpha = info->src->alpha;
	if(alpha == 128) {
		BlitRGBtoRGBSurfaceAlpha128(info);
	} else {
		int width = info->d_width;
		int height = info->d_height;
		Uint32 *srcp = (Uint32 *)info->s_pixels;
		int srcskip = info->s_skip >> 2;
		Uint32 *dstp = (Uint32 *)info->d_pixels;
		int dstskip = info->d_skip >> 2;
		Uint32 s;
		Uint32 d;
		Uint32 s1;
		Uint32 d1;

		while(height--) {
			DUFFS_LOOP_DOUBLE2({
				/* One Pixel Blend */
				s = *srcp;
				d = *dstp;
				s1 = s & 0xff00ff;
				d1 = d & 0xff00ff;
				d1 = (d1 + ((s1 - d1) * alpha >> 8))
				     & 0xff00ff;
				s &= 0xff00;
				d &= 0xff00;
				d = (d + ((s - d) * alpha >> 8)) & 0xff00;
				*dstp = d1 | d | 0xff000000;
				++srcp;
				++dstp;
			},{
			        /* Two Pixels Blend */
				s = *srcp;
				d = *dstp;
				s1 = s & 0xff00ff;
				d1 = d & 0xff00ff;
				d1 += (s1 - d1) * alpha >> 8;
				d1 &= 0xff00ff;
				     
				s = ((s & 0xff00) >> 8) | 
					((srcp[1] & 0xff00) << 8);
				d = ((d & 0xff00) >> 8) |
					((dstp[1] & 0xff00) << 8);
				d += (s - d) * alpha >> 8;
				d &= 0x00ff00ff;
				
				*dstp++ = d1 | ((d << 8) & 0xff00) | 0xff000000;
				++srcp;
				
			        s1 = *srcp;
				d1 = *dstp;
				s1 &= 0xff00ff;
				d1 &= 0xff00ff;
				d1 += (s1 - d1) * alpha >> 8;
				d1 &= 0xff00ff;
				
				*dstp = d1 | ((d >> 8) & 0xff00) | 0xff000000;
				++srcp;
				++dstp;
			}, width);
			srcp += srcskip;
			dstp += dstskip;
		}
	}
}

/* fast ARGB888->(A)RGB888 blending with pixel alpha */
static void BlitRGBtoRGBPixelAlpha(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint32 *srcp = (Uint32 *)info->s_pixels;
	int srcskip = info->s_skip >> 2;
	Uint32 *dstp = (Uint32 *)info->d_pixels;
	int dstskip = info->d_skip >> 2;

	while(height--) {
	    DUFFS_LOOP4({
		Uint32 dalpha;
		Uint32 d;
		Uint32 s1;
		Uint32 d1;
		Uint32 s = *srcp;
		Uint32 alpha = s >> 24;
		/* FIXME: Here we special-case opaque alpha since the
		   compositioning used (>>8 instead of /255) doesn't handle
		   it correctly. Also special-case alpha=0 for speed?
		   Benchmark this! */
		if(alpha) {   
		  if(alpha == SDL_ALPHA_OPAQUE) {
		    *dstp = (s & 0x00ffffff) | (*dstp & 0xff000000);
		  } else {
		    /*
		     * take out the middle component (green), and process
		     * the other two in parallel. One multiply less.
		     */
		    d = *dstp;
		    dalpha = d & 0xff000000;
		    s1 = s & 0xff00ff;
		    d1 = d & 0xff00ff;
		    d1 = (d1 + ((s1 - d1) * alpha >> 8)) & 0xff00ff;
		    s &= 0xff00;
		    d &= 0xff00;
		    d = (d + ((s - d) * alpha >> 8)) & 0xff00;
		    *dstp = d1 | d | dalpha;
		  }
		}
		++srcp;
		++dstp;
	    }, width);
	    srcp += srcskip;
	    dstp += dstskip;
	}
}

#ifdef MMX_ASMBLIT
/* fast (as in MMX with prefetch) ARGB888->(A)RGB888 blending with pixel alpha */
inline static void BlitRGBtoRGBPixelAlphaMMX3DNOW(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint32 *srcp = (Uint32 *)info->s_pixels;
	int srcskip = info->s_skip >> 2;
	Uint32 *dstp = (Uint32 *)info->d_pixels;
	int dstskip = info->d_skip >> 2;

	Uint32 s;
	Uint32 alpha;

	__asm__ (
	/* make mm6 all zeros. */
	"pxor       %%mm6, %%mm6\n"
	
	/* Make a mask to preserve the alpha. */
	"pcmpeqb   %%mm7, %%mm7\n\t"            /* mm7(s) = FF FF FF FF | FF FF FF FF */
	"psrlq     $16, %%mm7\n\t"		    /* mm7(s) = 00 00 FF FF | FF FF FF FF */

		: );

	while(height--) {

	    DUFFS_LOOP4({

		__asm__ (
		"prefetch 64(%0)\n"
		"prefetch 64(%1)\n"
			: : "r" (srcp), "r" (dstp) );

		s = *srcp;
		alpha = s >> 24;
		/* FIXME: Here we special-case opaque alpha since the
		   compositioning used (>>8 instead of /255) doesn't handle
		   it correctly. Also special-case alpha=0 for speed?
		   Benchmark this! */
		
		if(alpha == SDL_ALPHA_OPAQUE) {
		    *dstp = (s & 0x00ffffff) | (*dstp & 0xff000000);
		} 

		else {
			    __asm__ (
		    /* load in the source, and dst. */
		    "movd      (%0), %%mm0\n"		    /* mm0(s) = 0 0 0 0 | As Rs Gs Bs */
		    "movd      (%1), %%mm1\n"		    /* mm1(d) = 0 0 0 0 | Ad Rd Gd Bd */

		    /* Move the src alpha into mm2 */

		    /* if supporting pshufw */
		    /*"pshufw     $0x55, %%mm0, %%mm2\n" */ /* mm2 = 0 As 0 As |  0 As  0  As */
		    /*"psrlw     $8, %%mm2\n" */
		    
		    /* else: */
		    "movq      %%mm0, %%mm2\n"
		    "psrld     $24, %%mm2\n"                /* mm2 = 0 0 0 0 | 0  0  0  As */
		    "punpcklwd	%%mm2, %%mm2\n"	            /* mm2 = 0 0 0 0 |  0 As  0  As */
		    "punpckldq	%%mm2, %%mm2\n"             /* mm2 = 0 As 0 As |  0 As  0  As */

		    /* move the colors into words. */
		    "punpcklbw %%mm6, %%mm0\n"		    /* mm0 = 0 As 0 Rs | 0 Gs 0 Bs */
		    "punpcklbw %%mm6, %%mm1\n"              /* mm0 = 0 Ad 0 Rd | 0 Gd 0 Bd */

		    /* src - dst */
		    "psubw    %%mm1, %%mm0\n"		    /* mm0 = As-Ad Rs-Rd | Gs-Gd  Bs-Bd */

		    /* A * (src-dst) */
		    "pmullw    %%mm2, %%mm0\n"		    /* mm0 = As*As-d As*Rs-d | As*Gs-d  As*Bs-d */
		    "pand      %%mm7, %%mm0\n"              /* to preserve dest alpha */
		    "psrlw     $8,    %%mm0\n"		    /* mm0 = Ac>>8 Rc>>8 | Gc>>8  Bc>>8 */
		    "paddb     %%mm1, %%mm0\n"		    /* mm0 = Ac+Ad Rc+Rd | Gc+Gd  Bc+Bd */

		    "packuswb  %%mm0, %%mm0\n"              /* mm0 =             | Ac Rc Gc Bc */
		    
		    "movd      %%mm0, (%1)\n"               /* result in mm0 */

		     : : "r" (srcp), "r" (dstp) );

		}
		++srcp;
		++dstp;
	    }, width);
	    srcp += srcskip;
	    dstp += dstskip;
	}

	__asm__ (
	"emms\n"
		:   );
}
#endif

/* 16bpp special case for per-surface alpha=50%: blend 2 pixels in parallel */

/* blend a single 16 bit pixel at 50% */
#define BLEND16_50(d, s, mask)						\
	((((s & mask) + (d & mask)) >> 1) + (s & d & (~mask & 0xffff)))

/* blend two 16 bit pixels at 50% */
#define BLEND2x16_50(d, s, mask)					     \
	(((s & (mask | mask << 16)) >> 1) + ((d & (mask | mask << 16)) >> 1) \
	 + (s & d & (~(mask | mask << 16))))

static void Blit16to16SurfaceAlpha128(SDL_BlitInfo *info, Uint16 mask)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint16 *srcp = (Uint16 *)info->s_pixels;
	int srcskip = info->s_skip >> 1;
	Uint16 *dstp = (Uint16 *)info->d_pixels;
	int dstskip = info->d_skip >> 1;

	while(height--) {
		if(((unsigned long)srcp ^ (unsigned long)dstp) & 2) {
			/*
			 * Source and destination not aligned, pipeline it.
			 * This is mostly a win for big blits but no loss for
			 * small ones
			 */
			Uint32 prev_sw;
			int w = width;

			/* handle odd destination */
			if((unsigned long)dstp & 2) {
				Uint16 d = *dstp, s = *srcp;
				*dstp = BLEND16_50(d, s, mask);
				dstp++;
				srcp++;
				w--;
			}
			srcp++;	/* srcp is now 32-bit aligned */

			/* bootstrap pipeline with first halfword */
			prev_sw = ((Uint32 *)srcp)[-1];

			while(w > 1) {
				Uint32 sw, dw, s;
				sw = *(Uint32 *)srcp;
				dw = *(Uint32 *)dstp;
				if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
					s = (prev_sw << 16) + (sw >> 16);
				else
					s = (prev_sw >> 16) + (sw << 16);
				prev_sw = sw;
				*(Uint32 *)dstp = BLEND2x16_50(dw, s, mask);
				dstp += 2;
				srcp += 2;
				w -= 2;
			}

			/* final pixel if any */
			if(w) {
				Uint16 d = *dstp, s;
				if(SDL_BYTEORDER == SDL_BIG_ENDIAN)
					s = prev_sw;
				else
					s = prev_sw >> 16;
				*dstp = BLEND16_50(d, s, mask);
				srcp++;
				dstp++;
			}
			srcp += srcskip - 1;
			dstp += dstskip;
		} else {
			/* source and destination are aligned */
			int w = width;

			/* first odd pixel? */
			if((unsigned long)srcp & 2) {
				Uint16 d = *dstp, s = *srcp;
				*dstp = BLEND16_50(d, s, mask);
				srcp++;
				dstp++;
				w--;
			}
			/* srcp and dstp are now 32-bit aligned */

			while(w > 1) {
				Uint32 sw = *(Uint32 *)srcp;
				Uint32 dw = *(Uint32 *)dstp;
				*(Uint32 *)dstp = BLEND2x16_50(dw, sw, mask);
				srcp += 2;
				dstp += 2;
				w -= 2;
			}

			/* last odd pixel? */
			if(w) {
				Uint16 d = *dstp, s = *srcp;
				*dstp = BLEND16_50(d, s, mask);
				srcp++;
				dstp++;
			}
			srcp += srcskip;
			dstp += dstskip;
		}
	}
}

#ifdef MMX_ASMBLIT
/* fast RGB565->RGB565 blending with surface alpha */
static void Blit565to565SurfaceAlphaMMX(SDL_BlitInfo *info)
{
	unsigned alpha = info->src->alpha; /* downscale alpha to 5 bits */
	if(alpha == 128) {
		Blit16to16SurfaceAlpha128(info, 0xf7de);
	} else {
		int width = info->d_width;
		int height = info->d_height;
		Uint16 *srcp = (Uint16 *)info->s_pixels;
		int srcskip = info->s_skip >> 1;
		Uint16 *dstp = (Uint16 *)info->d_pixels;
		int dstskip = info->d_skip >> 1;
	        Uint32 s, d;
	        Uint8 load[8];
	  
		alpha &= ~(1+2+4);		/* cut alpha to get the exact same behaviour */
	        *(Uint64 *)load = alpha;
		alpha >>= 3;		/* downscale alpha to 5 bits */

                movq_m2r(*load, mm0); /* alpha(0000000A) -> mm0 */
                punpcklwd_r2r(mm0, mm0); /* 00000A0A -> mm0 */
                punpcklwd_r2r(mm0, mm0); /* 0A0A0A0A -> mm0 */
	  
 	        /* Setup the 565 color channel masks */
	        *(Uint64 *)load = 0xF800F800F800F800ULL;
		movq_m2r(*load, mm1); /* MASKRED -> mm1 */
		*(Uint64 *)load = 0x07E007E007E007E0ULL;
		movq_m2r(*load, mm4); /* MASKGREEN -> mm4 */
		*(Uint64 *)load = 0x001F001F001F001FULL;
		movq_m2r(*load, mm7); /* MASKBLUE -> mm7 */
		while(height--) {
                        DUFFS_LOOP_QUATRO2(
                        {
	                        s = *srcp++;
				d = *dstp;
				/*
				 * shift out the middle component (green) to
				 * the high 16 bits, and process all three RGB
				 * components at the same time.
				 */
				s = (s | s << 16) & 0x07e0f81f;
				d = (d | d << 16) & 0x07e0f81f;
				d += (s - d) * alpha >> 5;
				d &= 0x07e0f81f;
				*dstp++ = d | d >> 16;
                        },{
	                        s = *srcp++;
				d = *dstp;
				/*
				 * shift out the middle component (green) to
				 * the high 16 bits, and process all three RGB
				 * components at the same time.
				 */
				s = (s | s << 16) & 0x07e0f81f;
				d = (d | d << 16) & 0x07e0f81f;
				d += (s - d) * alpha >> 5;
				d &= 0x07e0f81f;
				*dstp++ = d | d >> 16;
			        s = *srcp++;
				d = *dstp;
				/*
				 * shift out the middle component (green) to
				 * the high 16 bits, and process all three RGB
				 * components at the same time.
				 */
				s = (s | s << 16) & 0x07e0f81f;
				d = (d | d << 16) & 0x07e0f81f;
				d += (s - d) * alpha >> 5;
				d &= 0x07e0f81f;
				*dstp++ = d | d >> 16;
                        },{
	                        movq_m2r((*dstp), mm3);/* 4 dst pixels -> mm3 */
	                        movq_m2r((*srcp), mm2);/* 4 src pixels -> mm2 */
			  
	                        /* RED */
	                        movq_r2r(mm2, mm5); /* src -> mm5 */
	                        pand_r2r(mm1 , mm5); /* src & MASKRED -> mm5 */
	                        psrlq_i2r(11, mm5); /* mm5 >> 11 -> mm5 [000r 000r 000r 000r] */
	
	                        movq_r2r(mm3, mm6); /* dst -> mm6 */
	                        pand_r2r(mm1 , mm6); /* dst & MASKRED -> mm6 */
	                        psrlq_i2r(11, mm6); /* mm6 >> 11 -> mm6 [000r 000r 000r 000r] */
	
	                        /* blend */
	                        psubw_r2r(mm6, mm5);/* src - dst -> mm5 */
	                        pmullw_r2r(mm0, mm5); /* mm5 * alpha -> mm5 */
	                        psrlw_i2r(8, mm5); /* mm5 >> 8 -> mm5 */
	                        paddw_r2r(mm5, mm6); /* mm5 + mm6(dst) -> mm6 */
	                        psllq_i2r(11, mm6); /* mm6 << 11 -> mm6 */
	                        pand_r2r(mm1, mm6); /* mm6 & MASKRED -> mm6 */
	
	                        movq_r2r(mm4, mm5); /* MASKGREEN -> mm5 */
	                        por_r2r(mm7, mm5);  /* MASKBLUE | mm5 -> mm5 */
	                        pand_r2r(mm5, mm3); /* mm3 & mm5(!MASKRED) -> mm3 */
	                        por_r2r(mm6, mm3); /* save new reds in dsts */
	
	                        /* green */
	                        movq_r2r(mm2, mm5); /* src -> mm5 */
	                        pand_r2r(mm4 , mm5); /* src & MASKGREEN -> mm5 */
	                        psrlq_i2r(5, mm5); /* mm5 >> 5 -> mm5 [000g 000g 000g 000g] */
	
	                        movq_r2r(mm3, mm6); /* dst -> mm6 */
	                        pand_r2r(mm4 , mm6); /* dst & MASKGREEN -> mm6 */
	                        psrlq_i2r(5, mm6); /* mm6 >> 5 -> mm6 [000g 000g 000g 000g] */
	
	                        /* blend */
	                        psubw_r2r(mm6, mm5);/* src - dst -> mm5 */
	                        pmullw_r2r(mm0, mm5); /* mm5 * alpha -> mm5 */
	                        psrlw_i2r(8, mm5); /* mm5 >> 8 -> mm5 */
	                        paddw_r2r(mm5, mm6); /* mm5 + mm6(dst) -> mm6 */
	                        psllq_i2r(5, mm6); /* mm6 << 5 -> mm6 */
	                        pand_r2r(mm4, mm6); /* mm6 & MASKGREEN -> mm6 */
	
	                        movq_r2r(mm1, mm5); /* MASKRED -> mm5 */
	                        por_r2r(mm7, mm5);  /* MASKBLUE | mm5 -> mm5 */
	                        pand_r2r(mm5, mm3); /* mm3 & mm5(!MASKGREEN) -> mm3 */
	                        por_r2r(mm6, mm3); /* save new greens in dsts */
	
	                        /* blue */
	                        movq_r2r(mm2, mm5); /* src -> mm5 */
	                        pand_r2r(mm7 , mm5); /* src & MASKRED -> mm5[000b 000b 000b 000b] */
		
	                        movq_r2r(mm3, mm6); /* dst -> mm6 */
	                        pand_r2r(mm7 , mm6); /* dst & MASKBLUE -> mm6[000b 000b 000b 000b] */
	
	                        /* blend */
	                        psubw_r2r(mm6, mm5);/* src - dst -> mm5 */
	                        pmullw_r2r(mm0, mm5); /* mm5 * alpha -> mm5 */
	                        psrlw_i2r(8, mm5); /* mm5 >> 8 -> mm5 */
	                        paddw_r2r(mm5, mm6); /* mm5 + mm6(dst) -> mm6 */
	                        pand_r2r(mm7, mm6); /* mm6 & MASKBLUE -> mm6 */
	
	                        movq_r2r(mm1, mm5); /* MASKRED -> mm5 */
	                        por_r2r(mm4, mm5);  /* MASKGREEN | mm5 -> mm5 */
	                        pand_r2r(mm5, mm3); /* mm3 & mm5(!MASKBLUE) -> mm3 */
	                        por_r2r(mm6, mm3); /* save new blues in dsts */
	
	                        movq_r2m(mm3, *dstp);/* mm3 -> 4 dst pixels */
	
	                        srcp += 4;
	                        dstp += 4;
                        }, width);			
			srcp += srcskip;
			dstp += dstskip;
		}
		emms();
	}
}

/* fast RGB555->RGB555 blending with surface alpha */
static void Blit555to555SurfaceAlphaMMX(SDL_BlitInfo *info)
{
	unsigned alpha = info->src->alpha; /* downscale alpha to 5 bits */
	if(alpha == 128) {
		Blit16to16SurfaceAlpha128(info, 0xfbde);
	} else {
		int width = info->d_width;
		int height = info->d_height;
		Uint16 *srcp = (Uint16 *)info->s_pixels;
		int srcskip = info->s_skip >> 1;
		Uint16 *dstp = (Uint16 *)info->d_pixels;
		int dstskip = info->d_skip >> 1;
	        Uint32 s, d;
	        Uint8 load[8];
	  
		alpha &= ~(1+2+4);		/* cut alpha to get the exact same behaviour */
	        *(Uint64 *)load = alpha;
		alpha >>= 3;		/* downscale alpha to 5 bits */

                movq_m2r(*load, mm0); /* alpha(0000000A) -> mm0 */
                punpcklwd_r2r(mm0, mm0); /* 00000A0A -> mm0 */
                punpcklwd_r2r(mm0, mm0); /* 0A0A0A0A -> mm0 */
	  
 	        /* Setup the 555 color channel masks */
	        *(Uint64 *)load = 0x7C007C007C007C00ULL;
		movq_m2r(*load, mm1); /* MASKRED -> mm1 */
		*(Uint64 *)load = 0x03E003E003E003E0ULL;
		movq_m2r(*load, mm4); /* MASKGREEN -> mm4 */
		*(Uint64 *)load = 0x001F001F001F001FULL;
		movq_m2r(*load, mm7); /* MASKBLUE -> mm7 */
		while(height--) {
                        DUFFS_LOOP_QUATRO2(
                        {
	                        s = *srcp++;
				d = *dstp;
				/*
				 * shift out the middle component (green) to
				 * the high 16 bits, and process all three RGB
				 * components at the same time.
				 */
				s = (s | s << 16) & 0x03e07c1f;
				d = (d | d << 16) & 0x03e07c1f;
				d += (s - d) * alpha >> 5;
				d &= 0x03e07c1f;
				*dstp++ = d | d >> 16;
                        },{
	                        s = *srcp++;
				d = *dstp;
				/*
				 * shift out the middle component (green) to
				 * the high 16 bits, and process all three RGB
				 * components at the same time.
				 */
				s = (s | s << 16) & 0x03e07c1f;
				d = (d | d << 16) & 0x03e07c1f;
				d += (s - d) * alpha >> 5;
				d &= 0x03e07c1f;
				*dstp++ = d | d >> 16;
			        s = *srcp++;
				d = *dstp;
				/*
				 * shift out the middle component (green) to
				 * the high 16 bits, and process all three RGB
				 * components at the same time.
				 */
				s = (s | s << 16) & 0x03e07c1f;
				d = (d | d << 16) & 0x03e07c1f;
				d += (s - d) * alpha >> 5;
				d &= 0x03e07c1f;
				*dstp++ = d | d >> 16;
                        },{
	                        movq_m2r((*dstp), mm3);/* 4 dst pixels -> mm3 */
	                        movq_m2r((*srcp), mm2);/* 4 src pixels -> mm2 */
			  
	                        /* RED */
	                        movq_r2r(mm2, mm5); /* src -> mm5 */
	                        pand_r2r(mm1 , mm5); /* src & MASKRED -> mm5 */
	                        psrlq_i2r(10, mm5); /* mm5 >> 10 -> mm5 [000r 000r 000r 000r] */
	
	                        movq_r2r(mm3, mm6); /* dst -> mm6 */
	                        pand_r2r(mm1 , mm6); /* dst & MASKRED -> mm6 */
	                        psrlq_i2r(10, mm6); /* mm6 >> 10 -> mm6 [000r 000r 000r 000r] */
	
	                        /* blend */
	                        psubw_r2r(mm6, mm5);/* src - dst -> mm5 */
	                        pmullw_r2r(mm0, mm5); /* mm5 * alpha -> mm5 */
	                        psrlw_i2r(8, mm5); /* mm5 >> 8 -> mm5 */
	                        paddw_r2r(mm5, mm6); /* mm5 + mm6(dst) -> mm6 */
	                        psllq_i2r(10, mm6); /* mm6 << 10 -> mm6 */
	                        pand_r2r(mm1, mm6); /* mm6 & MASKRED -> mm6 */
	
	                        movq_r2r(mm4, mm5); /* MASKGREEN -> mm5 */
	                        por_r2r(mm7, mm5);  /* MASKBLUE | mm5 -> mm5 */
	                        pand_r2r(mm5, mm3); /* mm3 & mm5(!MASKRED) -> mm3 */
	                        por_r2r(mm6, mm3); /* save new reds in dsts */
	
	                        /* green */
	                        movq_r2r(mm2, mm5); /* src -> mm5 */
	                        pand_r2r(mm4 , mm5); /* src & MASKGREEN -> mm5 */
	                        psrlq_i2r(5, mm5); /* mm5 >> 5 -> mm5 [000g 000g 000g 000g] */
	
	                        movq_r2r(mm3, mm6); /* dst -> mm6 */
	                        pand_r2r(mm4 , mm6); /* dst & MASKGREEN -> mm6 */
	                        psrlq_i2r(5, mm6); /* mm6 >> 5 -> mm6 [000g 000g 000g 000g] */
	
	                        /* blend */
	                        psubw_r2r(mm6, mm5);/* src - dst -> mm5 */
	                        pmullw_r2r(mm0, mm5); /* mm5 * alpha -> mm5 */
	                        psrlw_i2r(8, mm5); /* mm5 >> 8 -> mm5 */
	                        paddw_r2r(mm5, mm6); /* mm5 + mm6(dst) -> mm6 */
	                        psllq_i2r(5, mm6); /* mm6 << 5 -> mm6 */
	                        pand_r2r(mm4, mm6); /* mm6 & MASKGREEN -> mm6 */
	
	                        movq_r2r(mm1, mm5); /* MASKRED -> mm5 */
	                        por_r2r(mm7, mm5);  /* MASKBLUE | mm5 -> mm5 */
	                        pand_r2r(mm5, mm3); /* mm3 & mm5(!MASKGREEN) -> mm3 */
	                        por_r2r(mm6, mm3); /* save new greens in dsts */
	
	                        /* blue */
	                        movq_r2r(mm2, mm5); /* src -> mm5 */
	                        pand_r2r(mm7 , mm5); /* src & MASKRED -> mm5[000b 000b 000b 000b] */
		
	                        movq_r2r(mm3, mm6); /* dst -> mm6 */
	                        pand_r2r(mm7 , mm6); /* dst & MASKBLUE -> mm6[000b 000b 000b 000b] */
	
	                        /* blend */
	                        psubw_r2r(mm6, mm5);/* src - dst -> mm5 */
	                        pmullw_r2r(mm0, mm5); /* mm5 * alpha -> mm5 */
	                        psrlw_i2r(8, mm5); /* mm5 >> 8 -> mm5 */
	                        paddw_r2r(mm5, mm6); /* mm5 + mm6(dst) -> mm6 */
	                        pand_r2r(mm7, mm6); /* mm6 & MASKBLUE -> mm6 */
	
	                        movq_r2r(mm1, mm5); /* MASKRED -> mm5 */
	                        por_r2r(mm4, mm5);  /* MASKGREEN | mm5 -> mm5 */
	                        pand_r2r(mm5, mm3); /* mm3 & mm5(!MASKBLUE) -> mm3 */
	                        por_r2r(mm6, mm3); /* save new blues in dsts */
	
	                        movq_r2m(mm3, *dstp);/* mm3 -> 4 dst pixels */
	
	                        srcp += 4;
	                        dstp += 4;
                        }, width);			
			srcp += srcskip;
			dstp += dstskip;
		}
		emms();
	}
}
#endif

/* fast RGB565->RGB565 blending with surface alpha */
static void Blit565to565SurfaceAlpha(SDL_BlitInfo *info)
{
	unsigned alpha = info->src->alpha;
	if(alpha == 128) {
		Blit16to16SurfaceAlpha128(info, 0xf7de);
	} else {
		int width = info->d_width;
		int height = info->d_height;
		Uint16 *srcp = (Uint16 *)info->s_pixels;
		int srcskip = info->s_skip >> 1;
		Uint16 *dstp = (Uint16 *)info->d_pixels;
		int dstskip = info->d_skip >> 1;
		alpha >>= 3;	/* downscale alpha to 5 bits */

		while(height--) {
			DUFFS_LOOP4({
				Uint32 s = *srcp++;
				Uint32 d = *dstp;
				/*
				 * shift out the middle component (green) to
				 * the high 16 bits, and process all three RGB
				 * components at the same time.
				 */
				s = (s | s << 16) & 0x07e0f81f;
				d = (d | d << 16) & 0x07e0f81f;
				d += (s - d) * alpha >> 5;
				d &= 0x07e0f81f;
				*dstp++ = d | d >> 16;
			}, width);
			srcp += srcskip;
			dstp += dstskip;
		}
	}
}

/* fast RGB555->RGB555 blending with surface alpha */
static void Blit555to555SurfaceAlpha(SDL_BlitInfo *info)
{
	unsigned alpha = info->src->alpha; /* downscale alpha to 5 bits */
	if(alpha == 128) {
		Blit16to16SurfaceAlpha128(info, 0xfbde);
	} else {
		int width = info->d_width;
		int height = info->d_height;
		Uint16 *srcp = (Uint16 *)info->s_pixels;
		int srcskip = info->s_skip >> 1;
		Uint16 *dstp = (Uint16 *)info->d_pixels;
		int dstskip = info->d_skip >> 1;
		alpha >>= 3;		/* downscale alpha to 5 bits */

		while(height--) {
			DUFFS_LOOP4({
				Uint32 s = *srcp++;
				Uint32 d = *dstp;
				/*
				 * shift out the middle component (green) to
				 * the high 16 bits, and process all three RGB
				 * components at the same time.
				 */
				s = (s | s << 16) & 0x03e07c1f;
				d = (d | d << 16) & 0x03e07c1f;
				d += (s - d) * alpha >> 5;
				d &= 0x03e07c1f;
				*dstp++ = d | d >> 16;
			}, width);
			srcp += srcskip;
			dstp += dstskip;
		}
	}
}

/* fast ARGB8888->RGB565 blending with pixel alpha */
static void BlitARGBto565PixelAlpha(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint32 *srcp = (Uint32 *)info->s_pixels;
	int srcskip = info->s_skip >> 2;
	Uint16 *dstp = (Uint16 *)info->d_pixels;
	int dstskip = info->d_skip >> 1;

	while(height--) {
	    DUFFS_LOOP4({
		Uint32 s = *srcp;
		unsigned alpha = s >> 27; /* downscale alpha to 5 bits */
		/* FIXME: Here we special-case opaque alpha since the
		   compositioning used (>>8 instead of /255) doesn't handle
		   it correctly. Also special-case alpha=0 for speed?
		   Benchmark this! */
		if(alpha) {   
		  if(alpha == (SDL_ALPHA_OPAQUE >> 3)) {
		    *dstp = (s >> 8 & 0xf800) + (s >> 5 & 0x7e0)
			  + (s >> 3  & 0x1f);
		  } else {
		    Uint32 d = *dstp;
		    /*
		     * convert source and destination to G0RAB65565
		     * and blend all components at the same time
		     */
		    s = ((s & 0xfc00) << 11) + (s >> 8 & 0xf800)
		      + (s >> 3 & 0x1f);
		    d = (d | d << 16) & 0x07e0f81f;
		    d += (s - d) * alpha >> 5;
		    d &= 0x07e0f81f;
		    *dstp = d | d >> 16;
		  }
		}
		srcp++;
		dstp++;
	    }, width);
	    srcp += srcskip;
	    dstp += dstskip;
	}
}

/* fast ARGB8888->RGB555 blending with pixel alpha */
static void BlitARGBto555PixelAlpha(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint32 *srcp = (Uint32 *)info->s_pixels;
	int srcskip = info->s_skip >> 2;
	Uint16 *dstp = (Uint16 *)info->d_pixels;
	int dstskip = info->d_skip >> 1;

	while(height--) {
	    DUFFS_LOOP4({
		unsigned alpha;
		Uint32 s = *srcp;
		alpha = s >> 27; /* downscale alpha to 5 bits */
		/* FIXME: Here we special-case opaque alpha since the
		   compositioning used (>>8 instead of /255) doesn't handle
		   it correctly. Also special-case alpha=0 for speed?
		   Benchmark this! */
		if(alpha) {   
		  if(alpha == (SDL_ALPHA_OPAQUE >> 3)) {
		    *dstp = (s >> 9 & 0x7c00) + (s >> 6 & 0x3e0)
			  + (s >> 3  & 0x1f);
		  } else {
		    Uint32 d = *dstp;
		    /*
		     * convert source and destination to G0RAB65565
		     * and blend all components at the same time
		     */
		    s = ((s & 0xf800) << 10) + (s >> 9 & 0x7c00)
		      + (s >> 3 & 0x1f);
		    d = (d | d << 16) & 0x03e07c1f;
		    d += (s - d) * alpha >> 5;
		    d &= 0x03e07c1f;
		    *dstp = d | d >> 16;
		  }
		}
		srcp++;
		dstp++;
	    }, width);
	    srcp += srcskip;
	    dstp += dstskip;
	}
}

/* General (slow) N->N blending with per-surface alpha */
static void BlitNtoNSurfaceAlpha(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint8 *src = info->s_pixels;
	int srcskip = info->s_skip;
	Uint8 *dst = info->d_pixels;
	int dstskip = info->d_skip;
	SDL_PixelFormat *srcfmt = info->src;
	SDL_PixelFormat *dstfmt = info->dst;
	int srcbpp = srcfmt->BytesPerPixel;
	int dstbpp = dstfmt->BytesPerPixel;
	unsigned sA = srcfmt->alpha;
	unsigned dA = dstfmt->Amask ? SDL_ALPHA_OPAQUE : 0;

	if(sA) {
	  while ( height-- ) {
	    DUFFS_LOOP4(
	    {
		Uint32 pixel;
		unsigned sR;
		unsigned sG;
		unsigned sB;
		unsigned dR;
		unsigned dG;
		unsigned dB;
		DISEMBLE_RGB(src, srcbpp, srcfmt, pixel, sR, sG, sB);
		DISEMBLE_RGB(dst, dstbpp, dstfmt, pixel, dR, dG, dB);
		ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
		ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
		src += srcbpp;
		dst += dstbpp;
	    },
	    width);
	    src += srcskip;
	    dst += dstskip;
	  }
	}
}

/* General (slow) colorkeyed N->N blending with per-surface alpha */
static void BlitNtoNSurfaceAlphaKey(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint8 *src = info->s_pixels;
	int srcskip = info->s_skip;
	Uint8 *dst = info->d_pixels;
	int dstskip = info->d_skip;
	SDL_PixelFormat *srcfmt = info->src;
	SDL_PixelFormat *dstfmt = info->dst;
	Uint32 ckey = srcfmt->colorkey;
	int srcbpp = srcfmt->BytesPerPixel;
	int dstbpp = dstfmt->BytesPerPixel;
	unsigned sA = srcfmt->alpha;
	unsigned dA = dstfmt->Amask ? SDL_ALPHA_OPAQUE : 0;

	while ( height-- ) {
	    DUFFS_LOOP4(
	    {
		Uint32 pixel;
		unsigned sR;
		unsigned sG;
		unsigned sB;
		unsigned dR;
		unsigned dG;
		unsigned dB;
		RETRIEVE_RGB_PIXEL(src, srcbpp, pixel);
		if(sA && pixel != ckey) {
		    RGB_FROM_PIXEL(pixel, srcfmt, sR, sG, sB);
		    DISEMBLE_RGB(dst, dstbpp, dstfmt, pixel, dR, dG, dB);
		    ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
		    ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
		}
		src += srcbpp;
		dst += dstbpp;
	    },
	    width);
	    src += srcskip;
	    dst += dstskip;
	}
}

/* General (slow) N->N blending with pixel alpha */
static void BlitNtoNPixelAlpha(SDL_BlitInfo *info)
{
	int width = info->d_width;
	int height = info->d_height;
	Uint8 *src = info->s_pixels;
	int srcskip = info->s_skip;
	Uint8 *dst = info->d_pixels;
	int dstskip = info->d_skip;
	SDL_PixelFormat *srcfmt = info->src;
	SDL_PixelFormat *dstfmt = info->dst;

	int  srcbpp;
	int  dstbpp;

	/* Set up some basic variables */
	srcbpp = srcfmt->BytesPerPixel;
	dstbpp = dstfmt->BytesPerPixel;

	/* FIXME: for 8bpp source alpha, this doesn't get opaque values
	   quite right. for <8bpp source alpha, it gets them very wrong
	   (check all macros!)
	   It is unclear whether there is a good general solution that doesn't
	   need a branch (or a divide). */
	while ( height-- ) {
	    DUFFS_LOOP4(
	    {
		Uint32 pixel;
		unsigned sR;
		unsigned sG;
		unsigned sB;
		unsigned dR;
		unsigned dG;
		unsigned dB;
		unsigned sA;
		unsigned dA;
		DISEMBLE_RGBA(src, srcbpp, srcfmt, pixel, sR, sG, sB, sA);
		if(sA) {
		  DISEMBLE_RGBA(dst, dstbpp, dstfmt, pixel, dR, dG, dB, dA);
		  ALPHA_BLEND(sR, sG, sB, sA, dR, dG, dB);
		  ASSEMBLE_RGBA(dst, dstbpp, dstfmt, dR, dG, dB, dA);
		}
		src += srcbpp;
		dst += dstbpp;
	    },
	    width);
	    src += srcskip;
	    dst += dstskip;
	}
}


SDL_loblit SDL_CalculateAlphaBlit(SDL_Surface *surface, int blit_index)
{
    SDL_PixelFormat *sf = surface->format;
    SDL_PixelFormat *df = surface->map->dst->format;

    if(sf->Amask == 0) {
	if((surface->flags & SDL_SRCCOLORKEY) == SDL_SRCCOLORKEY) {
	    if(df->BytesPerPixel == 1)
		return BlitNto1SurfaceAlphaKey;
	    else
		return BlitNtoNSurfaceAlphaKey;
	} else {
	    /* Per-surface alpha blits */
	    switch(df->BytesPerPixel) {
	    case 1:
		return BlitNto1SurfaceAlpha;

	    case 2:
		if(surface->map->identity) {
		    if(df->Gmask == 0x7e0)
		    {
#ifdef MMX_ASMBLIT
		if(SDL_HasMMX())
			return Blit565to565SurfaceAlphaMMX;
		else
#endif
			return Blit565to565SurfaceAlpha;
		    }
		    else if(df->Gmask == 0x3e0)
		    {
#ifdef MMX_ASMBLIT
		if(SDL_HasMMX())
			return Blit555to555SurfaceAlphaMMX;
		else
#endif
			return Blit555to555SurfaceAlpha;
		    }
		}
		return BlitNtoNSurfaceAlpha;

	    case 4:
		if(sf->Rmask == df->Rmask
		   && sf->Gmask == df->Gmask
		   && sf->Bmask == df->Bmask
		   && (sf->Rmask | sf->Gmask | sf->Bmask) == 0xffffff
		   && sf->BytesPerPixel == 4)
		{
#ifdef MMX_ASMBLIT
		if(SDL_HasMMX())
		    return BlitRGBtoRGBSurfaceAlphaMMX;
		else
#endif
		    return BlitRGBtoRGBSurfaceAlpha;
		}
		else
		    return BlitNtoNSurfaceAlpha;

	    case 3:
	    default:
		return BlitNtoNSurfaceAlpha;
	    }
	}
    } else {
	/* Per-pixel alpha blits */
	switch(df->BytesPerPixel) {
	case 1:
	    return BlitNto1PixelAlpha;

	case 2:
	    if(sf->BytesPerPixel == 4 && sf->Amask == 0xff000000
	       && sf->Gmask == 0xff00
	       && ((sf->Rmask == 0xff && df->Rmask == 0x1f)
		   || (sf->Bmask == 0xff && df->Bmask == 0x1f))) {
		if(df->Gmask == 0x7e0)
		    return BlitARGBto565PixelAlpha;
		else if(df->Gmask == 0x3e0)
		    return BlitARGBto555PixelAlpha;
	    }
	    return BlitNtoNPixelAlpha;

	case 4:
	    if(sf->Amask == 0xff000000
	       && sf->Rmask == df->Rmask
	       && sf->Gmask == df->Gmask
	       && sf->Bmask == df->Bmask
	       && sf->BytesPerPixel == 4)
	    {
#ifdef MMX_ASMBLIT
		if(SDL_Has3DNow())
		    return BlitRGBtoRGBPixelAlphaMMX3DNOW;
		else
		if(SDL_HasMMX())
		    return BlitRGBtoRGBPixelAlphaMMX;
		else
#endif
		    return BlitRGBtoRGBPixelAlpha;
	    }
	    return BlitNtoNPixelAlpha;

	case 3:
	default:
	    return BlitNtoNPixelAlpha;
	}
    }
}