src/Unix/video_blit.cpp

/*
 *  video_blit.cpp - Video/graphics emulation, blitters
 *
 *  Basilisk II (C) 1997-2001 Christian Bauer
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "sysdeps.h"

#include <stdio.h>
#include <stdlib.h>
#include <X11/Xlib.h>
#include <X11/Xutil.h>

#ifdef ENABLE_VOSF
// Format of the target visual
struct VisualFormat {
        int             depth;                                  // Screen depth
        uint32  Rmask, Gmask, Bmask;    // RGB mask values
        uint32  Rshift, Gshift, Bshift; // RGB shift values
};
static VisualFormat visualFormat;

/* -------------------------------------------------------------------------- */
/* --- Raw Copy / No conversion required                                  --- */
/* -------------------------------------------------------------------------- */

static void Blit_Copy_Raw(uint8 * dest, const uint8 * source, uint32 length)
{
        // This function is likely to be inlined and/or highly optimized
        memcpy(dest, source, length);
}

/* -------------------------------------------------------------------------- */
/* --- RGB 555                                                            --- */
/* -------------------------------------------------------------------------- */

#ifdef WORDS_BIGENDIAN
# define FB_FUNC_NAME Blit_RGB555_OBO
#else
# define FB_FUNC_NAME Blit_RGB555_NBO
#endif

#define FB_BLIT_1(dst, src) \
        (dst = (((src) >> 8) & 0xff) | (((src) & 0xff) << 8))
        
#define FB_BLIT_2(dst, src) \
        (dst = (((src) >> 8) & 0x00ff00ff) | (((src) & 0x00ff00ff) << 8))

#define FB_DEPTH 15
#include "video_blit.h"

/* -------------------------------------------------------------------------- */
/* --- BGR 555                                                            --- */
/* -------------------------------------------------------------------------- */

// TODO: BGR 555 (SGI/Irix)
// R/G/B mask values: 0x001f, 0x03e0, 0x7c00

/* -------------------------------------------------------------------------- */
/* --- RGB 565                                                            --- */
/* -------------------------------------------------------------------------- */

#ifdef WORDS_BIGENDIAN

// Native byte order

#define FB_BLIT_1(dst, src) \
        (dst = (((src) & 0x1f) | (((src) << 1) & 0xffc0)))

#define FB_BLIT_2(dst, src) \
        (dst = (((src) & 0x001f001f) | (((src) << 1) & 0xffc0ffc0)))

#define FB_DEPTH 16
#define FB_FUNC_NAME Blit_RGB565_NBO
#include "video_blit.h"

// Opposite byte order

#define FB_BLIT_1(dst, src) \
        (dst = ((((src) >> 7) & 0xff) | (((src) << 9) & 0xc000) | (((src) << 8) & 0x1f00)))

#define FB_BLIT_2(dst, src) \
        (dst = ((((src) >> 7) & 0x00ff00ff) | (((src) << 9) & 0xc000c000) | (((src) << 8) & 0x1f001f00)))

#define FB_DEPTH 16
#define FB_FUNC_NAME Blit_RGB565_OBO
#include "video_blit.h"

#else

// Native byte order

#define FB_BLIT_1(dst, src) \
        (dst = (((src) >> 8) & 0x001f) | (((src) << 9) & 0xfe00) | (((src) >> 7) & 0x01c0))
        
// gb-- Disabled because I don't see any improvement
#if 0 && defined(__i386__) && defined(X86_ASSEMBLY)

#define FB_BLIT_2(dst, src) \
        __asm__ (       "movl %0,%%ebx\n\t" \
                                "movl %0,%%ebp\n\t" \
                                "andl $0x1f001f00,%%ebx\n\t" \
                                "andl $0x007f007f,%0\n\t" \
                                "andl $0xe000e000,%%ebp\n\t" \
                                "shrl $8,%%ebx\n\t" \
                                "shrl $7,%%ebp\n\t" \
                                "shll $9,%0\n\t" \
                                "orl %%ebx,%%ebp\n\t" \
                                "orl %%ebp,%0\n\t" \
                        : "=r" (dst) : "0" (src) : "ebx", "ebp", "cc" )

#else

#define FB_BLIT_2(dst, src) \
        (dst = (((src) >> 8) & 0x001f001f) | (((src) << 9) & 0xfe00fe00) | (((src) >> 7) & 0x01c001c0))

#endif

#define FB_DEPTH 16
#define FB_FUNC_NAME Blit_RGB565_NBO
#include "video_blit.h"

// Opposite byte order (untested)

#define FB_BLIT_1(dst, src) \
        (dst = (((src) & 0x1f00) | (((src) << 1) & 0xe0fe) | (((src) >> 15) & 1)))

#define FB_BLIT_2(dst, src) \
        (dst = (((src) & 0x1f001f00) | (((src) << 1) & 0xe0fee0fe) | (((src) >> 15) & 0x10001)))

#define FB_DEPTH 16
#define FB_FUNC_NAME Blit_RGB565_OBO
#include "video_blit.h"

#endif

/* -------------------------------------------------------------------------- */
/* --- RGB 888                                                            --- */
/* -------------------------------------------------------------------------- */

#ifdef WORDS_BIGENDIAN
# define FB_FUNC_NAME Blit_RGB888_OBO
#else
# define FB_FUNC_NAME Blit_RGB888_NBO
#endif

#define FB_BLIT_2(dst, src) \
        (dst = (((src) >> 24) & 0xff) | (((src) >> 8) & 0xff00) | (((src) & 0xff00) << 8) | (((src) & 0xff) << 24))

#define FB_DEPTH 24
#include "video_blit.h"

/* -------------------------------------------------------------------------- */
/* --- BGR 888                                                            --- */
/* -------------------------------------------------------------------------- */

// Native byte order (untested)

#ifdef WORDS_BIGENDIAN

#define FB_BLIT_2(dst, src) \
        (dst = (((src) >> 16) & 0xff) | ((src) & 0xff00) | (((src) & 0xff) << 16))

#define FB_FUNC_NAME Blit_BGR888_NBO
#define FB_DEPTH 24
#include "video_blit.h"

#else

#define FB_BLIT_2(dst, src) \
        (dst = (((src) >> 16) & 0xff) | ((src) & 0xff0000) | (((src) & 0xff) << 16))

#define FB_FUNC_NAME Blit_BGR888_OBO
#define FB_DEPTH 24
#include "video_blit.h"

#endif

// Opposite byte order (untested)

#ifdef WORDS_BIGENDIAN
# define FB_FUNC_NAME Blit_BGR888_OBO
#else
# define FB_FUNC_NAME Blit_BGR888_NBO
#endif

#define FB_BLIT_2(dst, src) \
        (dst = ((src) & 0xff00ff) | (((src) & 0xff00) << 16))

#define FB_DEPTH 24
#include "video_blit.h"

/* -------------------------------------------------------------------------- */
/* --- Blitters to the host frame buffer, or XImage buffer                --- */
/* -------------------------------------------------------------------------- */

// Function used to update the hosst frame buffer (DGA), or an XImage buffer (WIN)
// --> Shall be initialized only through the Screen_blitter_init() function
typedef void (*Screen_blit_func)(uint8 * dest, const uint8 * source, uint32 length);
Screen_blit_func Screen_blit = 0;

// Structure used to match the adequate framebuffer update function
struct Screen_blit_func_info {
        int                                     depth;                  // Screen depth
        uint32                          Rmask;                  // Red mask
        uint32                          Gmask;                  // Green mask
        uint32                          Bmask;                  // Blue mask
        Screen_blit_func        handler_nbo;    // Update function (native byte order)
        Screen_blit_func        handler_obo;    // Update function (opposite byte order)
};

// Table of visual formats supported and their respective handler
static Screen_blit_func_info Screen_blitters[] = {
#ifdef WORDS_BIGENDIAN
        {  1, 0x000000, 0x000000, 0x000000, Blit_Copy_Raw       , Blit_Copy_Raw         },      // NT
        {  8, 0x000000, 0x000000, 0x000000, Blit_Copy_Raw       , Blit_Copy_Raw         },      // OK (NBO)
        { 15, 0x007c00, 0x0003e0, 0x00001f, Blit_Copy_Raw       , Blit_RGB555_OBO       },      // OK (OBO)
        { 16, 0x00f800, 0x0007e0, 0x00001f, Blit_RGB565_NBO     , Blit_RGB565_OBO       },      // OK (OBO)
        { 24, 0xff0000, 0x00ff00, 0x0000ff, Blit_Copy_Raw       , Blit_RGB888_OBO       },      // OK (OBO)
        { 24, 0x0000ff, 0x00ff00, 0xff0000, Blit_BGR888_NBO     , Blit_BGR888_OBO       },      // NT
        { 32, 0xff0000, 0x00ff00, 0x0000ff, Blit_Copy_Raw       , Blit_RGB888_OBO       },      // OK (OBO)
        { 32, 0x0000ff, 0x00ff00, 0xff0000, Blit_BGR888_NBO     , Blit_BGR888_OBO       }       // NT
#else
        {  1, 0x000000, 0x000000, 0x000000, Blit_Copy_Raw       , Blit_Copy_Raw         },      // NT
        {  8, 0x000000, 0x000000, 0x000000, Blit_Copy_Raw       , Blit_Copy_Raw         },      // OK (NBO)
        { 15, 0x007c00, 0x0003e0, 0x00001f, Blit_RGB555_NBO     , Blit_Copy_Raw         },      // OK (NBO)
        { 16, 0x00f800, 0x0007e0, 0x00001f, Blit_RGB565_NBO     , Blit_RGB565_OBO       },      // OK (NBO)
        { 24, 0xff0000, 0x00ff00, 0x0000ff, Blit_RGB888_NBO     , Blit_Copy_Raw         },      // OK (NBO)
        { 24, 0x0000ff, 0x00ff00, 0xff0000, Blit_BGR888_NBO     , Blit_BGR888_OBO       },      // NT
        { 32, 0xff0000, 0x00ff00, 0x0000ff, Blit_RGB888_NBO     , Blit_Copy_Raw         },      // OK (NBO)
        { 32, 0x0000ff, 0x00ff00, 0xff0000, Blit_BGR888_NBO     , Blit_BGR888_OBO       }       // NT
#endif
};

// Initialize the framebuffer update function
// Returns FALSE, if the function was to be reduced to a simple memcpy()
// --> In that case, VOSF is not necessary
bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order)
{
        visualFormat.depth = visual_info->depth;
        visualFormat.Rmask = visual_info->red_mask;
        visualFormat.Gmask = visual_info->green_mask;
        visualFormat.Bmask = visual_info->blue_mask;
        
        // Compute RGB shift values
        visualFormat.Rshift = 0;
        for (uint32 Rmask = visualFormat.Rmask; Rmask && ((Rmask & 1) != 1); Rmask >>= 1)
                ++visualFormat.Rshift;
        visualFormat.Gshift = 0;
        for (uint32 Gmask = visualFormat.Gmask; Gmask && ((Gmask & 1) != 1); Gmask >>= 1)
                ++visualFormat.Gshift;
        visualFormat.Bshift = 0;
        for (uint32 Bmask = visualFormat.Bmask; Bmask && ((Bmask & 1) != 1); Bmask >>= 1)
                ++visualFormat.Bshift;
        
        // Search for an adequate blit function
        bool blitter_found = false;
        const int blitters_count = sizeof(Screen_blitters)/sizeof(Screen_blitters[0]);
        for (int i = 0; !blitter_found && (i < blitters_count); i++) {
                if      (       (visualFormat.depth == Screen_blitters[i].depth)
                        &&      (visualFormat.Rmask == Screen_blitters[i].Rmask)
                        &&      (visualFormat.Gmask == Screen_blitters[i].Gmask)
                        &&      (visualFormat.Bmask == Screen_blitters[i].Bmask)
                        )
                {
                        blitter_found = true;
                        Screen_blit = native_byte_order
                                                ? Screen_blitters[i].handler_nbo
                                                : Screen_blitters[i].handler_obo
                                                ;
                }
        }
        
        // No appropriate blitter found, dump RGB mask values and abort()
        if (!blitter_found) {
                fprintf(stderr, "### No appropriate blitter found\n");
                fprintf(stderr, "\tR/G/B mask values  : 0x%06x, 0x%06x, 0x%06x (depth = %d)\n",
                        visualFormat.Rmask, visualFormat.Gmask, visualFormat.Bmask, visualFormat.depth);
                fprintf(stderr, "\tR/G/B shift values : %d/%d/%d\n",
                        visualFormat.Rshift, visualFormat.Gshift, visualFormat.Bshift);
                abort();
        }
        
        // If the blitter simply reduces to a copy, we don't need VOSF in DGA mode
        // --> In that case, we return FALSE
        return (Screen_blit != Blit_Copy_Raw);
}
#endif /* ENABLE_VOSF */
Revision:	1.1
Committed:	2001-01-28T14:05:19Z (23 years, 9 months ago) by gbeauche
Branch:	MAIN
Log Message:	Mainly changes to the VOSF code: - improved blitters selection - improved blitters performance if UNALIGNED_PROFITABLE is set - cleaned up 8 bpp blitters
#	User	Rev	Content
1	gbeauche	1.1	/*
2			* video_blit.cpp - Video/graphics emulation, blitters
3			*
4			* Basilisk II (C) 1997-2001 Christian Bauer
5			*
6			* This program is free software; you can redistribute it and/or modify
7			* it under the terms of the GNU General Public License as published by
8			* the Free Software Foundation; either version 2 of the License, or
9			* (at your option) any later version.
10			*
11			* This program is distributed in the hope that it will be useful,
12			* but WITHOUT ANY WARRANTY; without even the implied warranty of
13			* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14			* GNU General Public License for more details.
15			*
16			* You should have received a copy of the GNU General Public License
17			* along with this program; if not, write to the Free Software
18			* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
19			*/
20
21			#include "sysdeps.h"
22
23			#include <stdio.h>
24			#include <stdlib.h>
25			#include <X11/Xlib.h>
26			#include <X11/Xutil.h>
27
28			#ifdef ENABLE_VOSF
29			// Format of the target visual
30			struct VisualFormat {
31			int depth; // Screen depth
32			uint32 Rmask, Gmask, Bmask; // RGB mask values
33			uint32 Rshift, Gshift, Bshift; // RGB shift values
34			};
35			static VisualFormat visualFormat;
36
37			/* -------------------------------------------------------------------------- */
38			/* --- Raw Copy / No conversion required --- */
39			/* -------------------------------------------------------------------------- */
40
41			static void Blit_Copy_Raw(uint8 * dest, const uint8 * source, uint32 length)
42			{
43			// This function is likely to be inlined and/or highly optimized
44			memcpy(dest, source, length);
45			}
46
47			/* -------------------------------------------------------------------------- */
48			/* --- RGB 555 --- */
49			/* -------------------------------------------------------------------------- */
50
51			#ifdef WORDS_BIGENDIAN
52			# define FB_FUNC_NAME Blit_RGB555_OBO
53			#else
54			# define FB_FUNC_NAME Blit_RGB555_NBO
55			#endif
56
57			#define FB_BLIT_1(dst, src) \
58			(dst = (((src) >> 8) & 0xff) \| (((src) & 0xff) << 8))
59
60			#define FB_BLIT_2(dst, src) \
61			(dst = (((src) >> 8) & 0x00ff00ff) \| (((src) & 0x00ff00ff) << 8))
62
63			#define FB_DEPTH 15
64			#include "video_blit.h"
65
66			/* -------------------------------------------------------------------------- */
67			/* --- BGR 555 --- */
68			/* -------------------------------------------------------------------------- */
69
70			// TODO: BGR 555 (SGI/Irix)
71			// R/G/B mask values: 0x001f, 0x03e0, 0x7c00
72
73			/* -------------------------------------------------------------------------- */
74			/* --- RGB 565 --- */
75			/* -------------------------------------------------------------------------- */
76
77			#ifdef WORDS_BIGENDIAN
78
79			// Native byte order
80
81			#define FB_BLIT_1(dst, src) \
82			(dst = (((src) & 0x1f) \| (((src) << 1) & 0xffc0)))
83
84			#define FB_BLIT_2(dst, src) \
85			(dst = (((src) & 0x001f001f) \| (((src) << 1) & 0xffc0ffc0)))
86
87			#define FB_DEPTH 16
88			#define FB_FUNC_NAME Blit_RGB565_NBO
89			#include "video_blit.h"
90
91			// Opposite byte order
92
93			#define FB_BLIT_1(dst, src) \
94			(dst = ((((src) >> 7) & 0xff) \| (((src) << 9) & 0xc000) \| (((src) << 8) & 0x1f00)))
95
96			#define FB_BLIT_2(dst, src) \
97			(dst = ((((src) >> 7) & 0x00ff00ff) \| (((src) << 9) & 0xc000c000) \| (((src) << 8) & 0x1f001f00)))
98
99			#define FB_DEPTH 16
100			#define FB_FUNC_NAME Blit_RGB565_OBO
101			#include "video_blit.h"
102
103			#else
104
105			// Native byte order
106
107			#define FB_BLIT_1(dst, src) \
108			(dst = (((src) >> 8) & 0x001f) \| (((src) << 9) & 0xfe00) \| (((src) >> 7) & 0x01c0))
109
110			// gb-- Disabled because I don't see any improvement
111			#if 0 && defined(__i386__) && defined(X86_ASSEMBLY)
112
113			#define FB_BLIT_2(dst, src) \
114			__asm__ ( "movl %0,%%ebx\n\t" \
115			"movl %0,%%ebp\n\t" \
116			"andl $0x1f001f00,%%ebx\n\t" \
117			"andl $0x007f007f,%0\n\t" \
118			"andl $0xe000e000,%%ebp\n\t" \
119			"shrl $8,%%ebx\n\t" \
120			"shrl $7,%%ebp\n\t" \
121			"shll $9,%0\n\t" \
122			"orl %%ebx,%%ebp\n\t" \
123			"orl %%ebp,%0\n\t" \
124			: "=r" (dst) : "0" (src) : "ebx", "ebp", "cc" )
125
126			#else
127
128			#define FB_BLIT_2(dst, src) \
129			(dst = (((src) >> 8) & 0x001f001f) \| (((src) << 9) & 0xfe00fe00) \| (((src) >> 7) & 0x01c001c0))
130
131			#endif
132
133			#define FB_DEPTH 16
134			#define FB_FUNC_NAME Blit_RGB565_NBO
135			#include "video_blit.h"
136
137			// Opposite byte order (untested)
138
139			#define FB_BLIT_1(dst, src) \
140			(dst = (((src) & 0x1f00) \| (((src) << 1) & 0xe0fe) \| (((src) >> 15) & 1)))
141
142			#define FB_BLIT_2(dst, src) \
143			(dst = (((src) & 0x1f001f00) \| (((src) << 1) & 0xe0fee0fe) \| (((src) >> 15) & 0x10001)))
144
145			#define FB_DEPTH 16
146			#define FB_FUNC_NAME Blit_RGB565_OBO
147			#include "video_blit.h"
148
149			#endif
150
151			/* -------------------------------------------------------------------------- */
152			/* --- RGB 888 --- */
153			/* -------------------------------------------------------------------------- */
154
155			#ifdef WORDS_BIGENDIAN
156			# define FB_FUNC_NAME Blit_RGB888_OBO
157			#else
158			# define FB_FUNC_NAME Blit_RGB888_NBO
159			#endif
160
161			#define FB_BLIT_2(dst, src) \
162			(dst = (((src) >> 24) & 0xff) \| (((src) >> 8) & 0xff00) \| (((src) & 0xff00) << 8) \| (((src) & 0xff) << 24))
163
164			#define FB_DEPTH 24
165			#include "video_blit.h"
166
167			/* -------------------------------------------------------------------------- */
168			/* --- BGR 888 --- */
169			/* -------------------------------------------------------------------------- */
170
171			// Native byte order (untested)
172
173			#ifdef WORDS_BIGENDIAN
174
175			#define FB_BLIT_2(dst, src) \
176			(dst = (((src) >> 16) & 0xff) \| ((src) & 0xff00) \| (((src) & 0xff) << 16))
177
178			#define FB_FUNC_NAME Blit_BGR888_NBO
179			#define FB_DEPTH 24
180			#include "video_blit.h"
181
182			#else
183
184			#define FB_BLIT_2(dst, src) \
185			(dst = (((src) >> 16) & 0xff) \| ((src) & 0xff0000) \| (((src) & 0xff) << 16))
186
187			#define FB_FUNC_NAME Blit_BGR888_OBO
188			#define FB_DEPTH 24
189			#include "video_blit.h"
190
191			#endif
192
193			// Opposite byte order (untested)
194
195			#ifdef WORDS_BIGENDIAN
196			# define FB_FUNC_NAME Blit_BGR888_OBO
197			#else
198			# define FB_FUNC_NAME Blit_BGR888_NBO
199			#endif
200
201			#define FB_BLIT_2(dst, src) \
202			(dst = ((src) & 0xff00ff) \| (((src) & 0xff00) << 16))
203
204			#define FB_DEPTH 24
205			#include "video_blit.h"
206
207			/* -------------------------------------------------------------------------- */
208			/* --- Blitters to the host frame buffer, or XImage buffer --- */
209			/* -------------------------------------------------------------------------- */
210
211			// Function used to update the hosst frame buffer (DGA), or an XImage buffer (WIN)
212			// --> Shall be initialized only through the Screen_blitter_init() function
213			typedef void (Screen_blit_func)(uint8 dest, const uint8 * source, uint32 length);
214			Screen_blit_func Screen_blit = 0;
215
216			// Structure used to match the adequate framebuffer update function
217			struct Screen_blit_func_info {
218			int depth; // Screen depth
219			uint32 Rmask; // Red mask
220			uint32 Gmask; // Green mask
221			uint32 Bmask; // Blue mask
222			Screen_blit_func handler_nbo; // Update function (native byte order)
223			Screen_blit_func handler_obo; // Update function (opposite byte order)
224			};
225
226			// Table of visual formats supported and their respective handler
227			static Screen_blit_func_info Screen_blitters[] = {
228			#ifdef WORDS_BIGENDIAN
229			{ 1, 0x000000, 0x000000, 0x000000, Blit_Copy_Raw , Blit_Copy_Raw }, // NT
230			{ 8, 0x000000, 0x000000, 0x000000, Blit_Copy_Raw , Blit_Copy_Raw }, // OK (NBO)
231			{ 15, 0x007c00, 0x0003e0, 0x00001f, Blit_Copy_Raw , Blit_RGB555_OBO }, // OK (OBO)
232			{ 16, 0x00f800, 0x0007e0, 0x00001f, Blit_RGB565_NBO , Blit_RGB565_OBO }, // OK (OBO)
233			{ 24, 0xff0000, 0x00ff00, 0x0000ff, Blit_Copy_Raw , Blit_RGB888_OBO }, // OK (OBO)
234			{ 24, 0x0000ff, 0x00ff00, 0xff0000, Blit_BGR888_NBO , Blit_BGR888_OBO }, // NT
235			{ 32, 0xff0000, 0x00ff00, 0x0000ff, Blit_Copy_Raw , Blit_RGB888_OBO }, // OK (OBO)
236			{ 32, 0x0000ff, 0x00ff00, 0xff0000, Blit_BGR888_NBO , Blit_BGR888_OBO } // NT
237			#else
238			{ 1, 0x000000, 0x000000, 0x000000, Blit_Copy_Raw , Blit_Copy_Raw }, // NT
239			{ 8, 0x000000, 0x000000, 0x000000, Blit_Copy_Raw , Blit_Copy_Raw }, // OK (NBO)
240			{ 15, 0x007c00, 0x0003e0, 0x00001f, Blit_RGB555_NBO , Blit_Copy_Raw }, // OK (NBO)
241			{ 16, 0x00f800, 0x0007e0, 0x00001f, Blit_RGB565_NBO , Blit_RGB565_OBO }, // OK (NBO)
242			{ 24, 0xff0000, 0x00ff00, 0x0000ff, Blit_RGB888_NBO , Blit_Copy_Raw }, // OK (NBO)
243			{ 24, 0x0000ff, 0x00ff00, 0xff0000, Blit_BGR888_NBO , Blit_BGR888_OBO }, // NT
244			{ 32, 0xff0000, 0x00ff00, 0x0000ff, Blit_RGB888_NBO , Blit_Copy_Raw }, // OK (NBO)
245			{ 32, 0x0000ff, 0x00ff00, 0xff0000, Blit_BGR888_NBO , Blit_BGR888_OBO } // NT
246			#endif
247			};
248
249			// Initialize the framebuffer update function
250			// Returns FALSE, if the function was to be reduced to a simple memcpy()
251			// --> In that case, VOSF is not necessary
252			bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order)
253			{
254			visualFormat.depth = visual_info->depth;
255			visualFormat.Rmask = visual_info->red_mask;
256			visualFormat.Gmask = visual_info->green_mask;
257			visualFormat.Bmask = visual_info->blue_mask;
258
259			// Compute RGB shift values
260			visualFormat.Rshift = 0;
261			for (uint32 Rmask = visualFormat.Rmask; Rmask && ((Rmask & 1) != 1); Rmask >>= 1)
262			++visualFormat.Rshift;
263			visualFormat.Gshift = 0;
264			for (uint32 Gmask = visualFormat.Gmask; Gmask && ((Gmask & 1) != 1); Gmask >>= 1)
265			++visualFormat.Gshift;
266			visualFormat.Bshift = 0;
267			for (uint32 Bmask = visualFormat.Bmask; Bmask && ((Bmask & 1) != 1); Bmask >>= 1)
268			++visualFormat.Bshift;
269
270			// Search for an adequate blit function
271			bool blitter_found = false;
272			const int blitters_count = sizeof(Screen_blitters)/sizeof(Screen_blitters[0]);
273			for (int i = 0; !blitter_found && (i < blitters_count); i++) {
274			if ( (visualFormat.depth == Screen_blitters[i].depth)
275			&& (visualFormat.Rmask == Screen_blitters[i].Rmask)
276			&& (visualFormat.Gmask == Screen_blitters[i].Gmask)
277			&& (visualFormat.Bmask == Screen_blitters[i].Bmask)
278			)
279			{
280			blitter_found = true;
281			Screen_blit = native_byte_order
282			? Screen_blitters[i].handler_nbo
283			: Screen_blitters[i].handler_obo
284			;
285			}
286			}
287
288			// No appropriate blitter found, dump RGB mask values and abort()
289			if (!blitter_found) {
290			fprintf(stderr, "### No appropriate blitter found\n");
291			fprintf(stderr, "\tR/G/B mask values : 0x%06x, 0x%06x, 0x%06x (depth = %d)\n",
292			visualFormat.Rmask, visualFormat.Gmask, visualFormat.Bmask, visualFormat.depth);
293			fprintf(stderr, "\tR/G/B shift values : %d/%d/%d\n",
294			visualFormat.Rshift, visualFormat.Gshift, visualFormat.Bshift);
295			abort();
296			}
297
298			// If the blitter simply reduces to a copy, we don't need VOSF in DGA mode
299			// --> In that case, we return FALSE
300			return (Screen_blit != Blit_Copy_Raw);
301			}
302			#endif /* ENABLE_VOSF */