src/Unix/video_vosf.h

/*
 *  video_vosf.h - Video/graphics emulation, video on SEGV signals support
 *
 *  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
 */

#ifndef VIDEO_VOSF_H
#define VIDEO_VOSF_H

// Note: this file is #include'd in video_x.cpp
#ifdef ENABLE_VOSF

/*
 *  Page-aligned memory allocation
 */

// Align on page boundaries
static uintptr align_on_page_boundary(uintptr size)
{
        const uint32 page_size = getpagesize();
        const uint32 page_mask = page_size - 1;
        return (size + page_mask) & ~page_mask;
}

// Allocate memory on page boundary
static void * allocate_framebuffer(uint32 size, uint8 * hint = 0)
{
        // Remind that the system can allocate at 0x00000000...
        return mmap((caddr_t)hint, size, PROT_READ | PROT_WRITE, MAP_PRIVATE, zero_fd, 0);
}


/*
 *      Screen fault handler
 */

const uintptr INVALID_PC = (uintptr)-1;

static inline void do_handle_screen_fault(uintptr addr, uintptr pc = INVALID_PC)
{
        /* Someone attempted to write to the frame buffer. Make it writeable
         * now so that the data could actually be written. It will be made
         * read-only back in one of the screen update_*() functions.
         */
        if ((addr >= mainBuffer.memStart) && (addr < mainBuffer.memEnd)) {
                const int page  = (addr - mainBuffer.memStart) >> mainBuffer.pageBits;
                caddr_t page_ad = (caddr_t)(addr & ~(mainBuffer.pageSize - 1));
                LOCK_VOSF;
                PFLAG_SET(page);
                mprotect(page_ad, mainBuffer.pageSize, PROT_READ | PROT_WRITE);
                mainBuffer.dirty = true;
                UNLOCK_VOSF;
                return;
        }
        
        /* Otherwise, we don't know how to handle the fault, let it crash */
        fprintf(stderr, "do_handle_screen_fault: unhandled address 0x%08X", addr);
        if (pc != INVALID_PC)
                fprintf(stderr, " [IP=0x%08X]", pc);
        fprintf(stderr, "\n");
        
        signal(SIGSEGV, SIG_DFL);
}

#if defined(HAVE_SIGINFO_T)

static void Screen_fault_handler(int, siginfo_t * sip, void *)
{
        D(bug("Screen_fault_handler: ADDR=0x%08X\n", sip->si_addr));
        do_handle_screen_fault((uintptr)sip->si_addr);
}

#elif defined(HAVE_SIGCONTEXT_SUBTERFUGE)

# if defined(__i386__) && defined(__linux__)
static void Screen_fault_handler(int, struct sigcontext scs)
{
        D(bug("Screen_fault_handler: ADDR=0x%08X from IP=0x%08X\n", scs.cr2, scs.eip));
        do_handle_screen_fault((uintptr)scs.cr2, (uintptr)scs.eip);
}

# elif defined(__m68k__) && defined(__NetBSD__)

# include <m68k/frame.h>
static void Screen_fault_handler(int, int code, struct sigcontext *scp)
{
        D(bug("Screen_fault_handler: ADDR=0x%08X\n", code));
        struct sigstate {
                int ss_flags;
                struct frame ss_frame;
        };
        struct sigstate *state = (struct sigstate *)scp->sc_ap;
        uintptr fault_addr;
        switch (state->ss_frame.f_format) {
                case 7:         // 68040 access error
                        // "code" is sometimes unreliable (i.e. contains NULL or a bogus address), reason unknown
                        fault_addr = state->ss_frame.f_fmt7.f_fa;
                        break;
                default:
                        fault_addr = (uintptr)code;
                        break;
        }
        do_handle_screen_fault(fault_addr);
}

# else
#  error "No suitable subterfuge for Video on SEGV signals"
# endif
#else
# error "Can't do Video on SEGV signals"
#endif


/*
 *      Screen fault handler initialization
 */

#if defined(HAVE_SIGINFO_T)
static bool Screen_fault_handler_init()
{
        // Setup SIGSEGV handler to process writes to frame buffer
        sigemptyset(&vosf_sa.sa_mask);
        vosf_sa.sa_sigaction = Screen_fault_handler;
        vosf_sa.sa_flags = SA_SIGINFO;
        return (sigaction(SIGSEGV, &vosf_sa, NULL) == 0);
}
#elif defined(HAVE_SIGCONTEXT_SUBTERFUGE)
static bool Screen_fault_handler_init()
{
        // Setup SIGSEGV handler to process writes to frame buffer
        sigemptyset(&vosf_sa.sa_mask);
        vosf_sa.sa_handler = (void (*)(int)) Screen_fault_handler;
#if !EMULATED_68K && defined(__NetBSD__)
        sigaddset(&vosf_sa.sa_mask, SIGALRM);
        vosf_sa.sa_flags = SA_ONSTACK;
#else
        vosf_sa.sa_flags = 0;
#endif
        return (sigaction(SIGSEGV, &vosf_sa, NULL) == 0);
}
#endif


/*
 *      Update display for Windowed mode and VOSF
 */

// From video_blit.cpp
extern void (*Screen_blit)(uint8 * dest, const uint8 * source, uint32 length);
extern bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order);

/*      How can we deal with array overrun conditions ?
        
        The state of the framebuffer pages that have been touched are maintained
        in the dirtyPages[] table. That table is (pageCount + 2) bytes long.

Terminology
        
        "Last Page" denotes the pageCount-nth page, i.e. dirtyPages[pageCount - 1].
        "CLEAR Page Guard" refers to the page following the Last Page but is always
        in the CLEAR state. "SET Page Guard" refers to the page following the CLEAR
        Page Guard but is always in the SET state.

Rough process
        
        The update routines must determine which pages have to be blitted to the
        screen. This job consists in finding the first_page that was touched.
        i.e. find the next page that is SET. Then, finding how many pages were
        touched starting from first_page. i.e. find the next page that is CLEAR.

There are two cases to check:

        - Last Page is CLEAR: find_next_page_set() will reach the SET Page Guard
        but it is beyond the valid pageCount value. Therefore, we exit from the
        update routine.
        
        - Last Page is SET: first_page equals (pageCount - 1) and
        find_next_page_clear() will reach the CLEAR Page Guard. We blit the last
        page to the screen. On the next iteration, page equals pageCount and
        find_next_page_set() will reach the SET Page Guard. We still safely exit
        from the update routine because the SET Page Guard position is greater
        than pageCount.
*/

static inline void update_display_window_vosf(void)
{
        int page = 0;
        for (;;) {
                const int first_page = find_next_page_set(page);
                if (first_page >= mainBuffer.pageCount)
                        break;

                page = find_next_page_clear(first_page);
                PFLAG_CLEAR_RANGE(first_page, page);

                // Make the dirty pages read-only again
                const int32 offset  = first_page << mainBuffer.pageBits;
                const uint32 length = (page - first_page) << mainBuffer.pageBits;
                mprotect((caddr_t)(mainBuffer.memStart + offset), length, PROT_READ);
                
                // There is at least one line to update
                const int y1 = mainBuffer.pageInfo[first_page].top;
                const int y2 = mainBuffer.pageInfo[page - 1].bottom;
                const int height = y2 - y1 + 1;
                
                const int bytes_per_row = VideoMonitor.bytes_per_row;
                const int bytes_per_pixel = VideoMonitor.bytes_per_row / VideoMonitor.x;
                int i, j;
                
                // Check for first column from left and first column
                // from right that have changed
                int x1, x2, width;
                if (depth == 1) {

                        x1 = VideoMonitor.x - 1;
                        for (j = y1; j <= y2; j++) {
                                uint8 * const p1 = &the_buffer[j * bytes_per_row];
                                uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
                                for (i = 0; i < (x1>>3); i++) {
                                        if (p1[i] != p2[i]) {
                                                x1 = i << 3;
                                                break;
                                        }
                                }
                        }

                        x2 = x1;
                        for (j = y2; j >= y1; j--) {
                                uint8 * const p1 = &the_buffer[j * bytes_per_row];
                                uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
                                for (i = (VideoMonitor.x>>3) - 1; i > (x2>>3); i--) {
                                        if (p1[i] != p2[i]) {
                                                x2 = (i << 3) + 7;
                                                break;
                                        }
                                }
                        }
                        width = x2 - x1 + 1;

                        // Update the_host_buffer and copy of the_buffer
                        i = y1 * bytes_per_row + (x1 >> 3);
                        for (j = y1; j <= y2; j++) {
                                Screen_blit(the_host_buffer + i, the_buffer + i, width >> 3);
                                memcpy(the_buffer_copy + i, the_buffer + i, width >> 3);
                                i += bytes_per_row;
                        }

                } else {

                        x1 = VideoMonitor.x * bytes_per_pixel - 1;
                        for (j = y1; j <= y2; j++) {
                                uint8 * const p1 = &the_buffer[j * bytes_per_row];
                                uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
                                for (i = 0; i < x1; i++) {
                                        if (p1[i] != p2[i]) {
                                                x1 = i;
                                                break;
                                        }
                                }
                        }
                        x1 /= bytes_per_pixel;
                
                        x2 = x1 * bytes_per_pixel;
                        for (j = y2; j >= y1; j--) {
                                uint8 * const p1 = &the_buffer[j * bytes_per_row];
                                uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
                                for (i = VideoMonitor.x * bytes_per_pixel - 1; i > x2; i--) {
                                        if (p1[i] != p2[i]) {
                                                x2 = i;
                                                break;
                                        }
                                }
                        }
                        x2 /= bytes_per_pixel;
                        width = x2 - x1 + 1;

                        // Update the_host_buffer and copy of the_buffer
                        i = y1 * bytes_per_row + x1 * bytes_per_pixel;
                        for (j = y1; j <= y2; j++) {
                                Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
                                memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
                                i += bytes_per_row;
                        }
                }
                
                if (have_shm)
                        XShmPutImage(x_display, the_win, the_gc, img, x1, y1, x1, y1, width, height, 0);
                else
                        XPutImage(x_display, the_win, the_gc, img, x1, y1, x1, y1, width, height);
        }
        mainBuffer.dirty = false;
}


/*
 *      Update display for DGA mode and VOSF
 *      (only in Direct Addressing mode)
 */

#if REAL_ADDRESSING || DIRECT_ADDRESSING
static inline void update_display_dga_vosf(void)
{
        int page = 0;
        for (;;) {
                const int first_page = find_next_page_set(page);
                if (first_page >= mainBuffer.pageCount)
                        break;

                page = find_next_page_clear(first_page);
                PFLAG_CLEAR_RANGE(first_page, page);

                // Make the dirty pages read-only again
                const int32 offset  = first_page << mainBuffer.pageBits;
                const uint32 length = (page - first_page) << mainBuffer.pageBits;
                mprotect((caddr_t)(mainBuffer.memStart + offset), length, PROT_READ);
                
                // I am sure that y2 >= y1 and depth != 1
                const int y1 = mainBuffer.pageInfo[first_page].top;
                const int y2 = mainBuffer.pageInfo[page - 1].bottom;
                
                const int bytes_per_row = VideoMonitor.bytes_per_row;
                const int bytes_per_pixel = VideoMonitor.bytes_per_row / VideoMonitor.x;
                int i, j;
                
                // Check for first column from left and first column
                // from right that have changed
                int x1 = VideoMonitor.x * bytes_per_pixel - 1;
                for (j = y1; j <= y2; j++) {
                        uint8 * const p1 = &the_buffer[j * bytes_per_row];
                        uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
                        for (i = 0; i < x1; i++) {
                                if (p1[i] != p2[i]) {
                                        x1 = i;
                                        break;
                                }
                        }
                }
                x1 /= bytes_per_pixel;
                
                int x2 = x1 * bytes_per_pixel;
                for (j = y2; j >= y1; j--) {
                        uint8 * const p1 = &the_buffer[j * bytes_per_row];
                        uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
                        for (i = VideoMonitor.x * bytes_per_pixel - 1; i > x2; i--) {
                                if (p1[i] != p2[i]) {
                                        x2 = i;
                                        break;
                                }
                        }
                }
                x2 /= bytes_per_pixel;
                
                // Update the_host_buffer and copy of the_buffer
                // There should be at least one pixel to copy
                const int width = x2 - x1 + 1;
                i = y1 * bytes_per_row + x1 * bytes_per_pixel;
                for (j = y1; j <= y2; j++) {
                        Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
                        memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
                        i += bytes_per_row;
                }
        }
        mainBuffer.dirty = false;
}
#endif

#endif /* ENABLE_VOSF */

#endif /* VIDEO_VOSF_H */
Revision:	1.13
Committed:	2001-01-28T14:05:19Z (23 years, 5 months ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
Changes since 1.12:	+13 -198 lines
Log Message:	Mainly changes to the VOSF code: - improved blitters selection - improved blitters performance if UNALIGNED_PROFITABLE is set - cleaned up 8 bpp blitters
#	Content
1	/*
2	* video_vosf.h - Video/graphics emulation, video on SEGV signals support
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	#ifndef VIDEO_VOSF_H
22	#define VIDEO_VOSF_H
23
24	// Note: this file is #include'd in video_x.cpp
25	#ifdef ENABLE_VOSF
26
27	/*
28	* Page-aligned memory allocation
29	*/
30
31	// Align on page boundaries
32	static uintptr align_on_page_boundary(uintptr size)
33	{
34	const uint32 page_size = getpagesize();
35	const uint32 page_mask = page_size - 1;
36	return (size + page_mask) & ~page_mask;
37	}
38
39	// Allocate memory on page boundary
40	static void * allocate_framebuffer(uint32 size, uint8 * hint = 0)
41	{
42	// Remind that the system can allocate at 0x00000000...
43	return mmap((caddr_t)hint, size, PROT_READ \| PROT_WRITE, MAP_PRIVATE, zero_fd, 0);
44	}
45
46
47	/*
48	* Screen fault handler
49	*/
50
51	const uintptr INVALID_PC = (uintptr)-1;
52
53	static inline void do_handle_screen_fault(uintptr addr, uintptr pc = INVALID_PC)
54	{
55	/* Someone attempted to write to the frame buffer. Make it writeable
56	* now so that the data could actually be written. It will be made
57	* read-only back in one of the screen update_*() functions.
58	*/
59	if ((addr >= mainBuffer.memStart) && (addr < mainBuffer.memEnd)) {
60	const int page = (addr - mainBuffer.memStart) >> mainBuffer.pageBits;
61	caddr_t page_ad = (caddr_t)(addr & ~(mainBuffer.pageSize - 1));
62	LOCK_VOSF;
63	PFLAG_SET(page);
64	mprotect(page_ad, mainBuffer.pageSize, PROT_READ \| PROT_WRITE);
65	mainBuffer.dirty = true;
66	UNLOCK_VOSF;
67	return;
68	}
69
70	/* Otherwise, we don't know how to handle the fault, let it crash */
71	fprintf(stderr, "do_handle_screen_fault: unhandled address 0x%08X", addr);
72	if (pc != INVALID_PC)
73	fprintf(stderr, " [IP=0x%08X]", pc);
74	fprintf(stderr, "\n");
75
76	signal(SIGSEGV, SIG_DFL);
77	}
78
79	#if defined(HAVE_SIGINFO_T)
80
81	static void Screen_fault_handler(int, siginfo_t * sip, void *)
82	{
83	D(bug("Screen_fault_handler: ADDR=0x%08X\n", sip->si_addr));
84	do_handle_screen_fault((uintptr)sip->si_addr);
85	}
86
87	#elif defined(HAVE_SIGCONTEXT_SUBTERFUGE)
88
89	# if defined(__i386__) && defined(__linux__)
90	static void Screen_fault_handler(int, struct sigcontext scs)
91	{
92	D(bug("Screen_fault_handler: ADDR=0x%08X from IP=0x%08X\n", scs.cr2, scs.eip));
93	do_handle_screen_fault((uintptr)scs.cr2, (uintptr)scs.eip);
94	}
95
96	# elif defined(__m68k__) && defined(__NetBSD__)
97
98	# include <m68k/frame.h>
99	static void Screen_fault_handler(int, int code, struct sigcontext *scp)
100	{
101	D(bug("Screen_fault_handler: ADDR=0x%08X\n", code));
102	struct sigstate {
103	int ss_flags;
104	struct frame ss_frame;
105	};
106	struct sigstate state = (struct sigstate )scp->sc_ap;
107	uintptr fault_addr;
108	switch (state->ss_frame.f_format) {
109	case 7: // 68040 access error
110	// "code" is sometimes unreliable (i.e. contains NULL or a bogus address), reason unknown
111	fault_addr = state->ss_frame.f_fmt7.f_fa;
112	break;
113	default:
114	fault_addr = (uintptr)code;
115	break;
116	}
117	do_handle_screen_fault(fault_addr);
118	}
119
120	# else
121	# error "No suitable subterfuge for Video on SEGV signals"
122	# endif
123	#else
124	# error "Can't do Video on SEGV signals"
125	#endif
126
127
128	/*
129	* Screen fault handler initialization
130	*/
131
132	#if defined(HAVE_SIGINFO_T)
133	static bool Screen_fault_handler_init()
134	{
135	// Setup SIGSEGV handler to process writes to frame buffer
136	sigemptyset(&vosf_sa.sa_mask);
137	vosf_sa.sa_sigaction = Screen_fault_handler;
138	vosf_sa.sa_flags = SA_SIGINFO;
139	return (sigaction(SIGSEGV, &vosf_sa, NULL) == 0);
140	}
141	#elif defined(HAVE_SIGCONTEXT_SUBTERFUGE)
142	static bool Screen_fault_handler_init()
143	{
144	// Setup SIGSEGV handler to process writes to frame buffer
145	sigemptyset(&vosf_sa.sa_mask);
146	vosf_sa.sa_handler = (void (*)(int)) Screen_fault_handler;
147	#if !EMULATED_68K && defined(__NetBSD__)
148	sigaddset(&vosf_sa.sa_mask, SIGALRM);
149	vosf_sa.sa_flags = SA_ONSTACK;
150	#else
151	vosf_sa.sa_flags = 0;
152	#endif
153	return (sigaction(SIGSEGV, &vosf_sa, NULL) == 0);
154	}
155	#endif
156
157
158	/*
159	* Update display for Windowed mode and VOSF
160	*/
161
162	// From video_blit.cpp
163	extern void (Screen_blit)(uint8 dest, const uint8 * source, uint32 length);
164	extern bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order);
165
166	/* How can we deal with array overrun conditions ?
167
168	The state of the framebuffer pages that have been touched are maintained
169	in the dirtyPages[] table. That table is (pageCount + 2) bytes long.
170
171	Terminology
172
173	"Last Page" denotes the pageCount-nth page, i.e. dirtyPages[pageCount - 1].
174	"CLEAR Page Guard" refers to the page following the Last Page but is always
175	in the CLEAR state. "SET Page Guard" refers to the page following the CLEAR
176	Page Guard but is always in the SET state.
177
178	Rough process
179
180	The update routines must determine which pages have to be blitted to the
181	screen. This job consists in finding the first_page that was touched.
182	i.e. find the next page that is SET. Then, finding how many pages were
183	touched starting from first_page. i.e. find the next page that is CLEAR.
184
185	There are two cases to check:
186
187	- Last Page is CLEAR: find_next_page_set() will reach the SET Page Guard
188	but it is beyond the valid pageCount value. Therefore, we exit from the
189	update routine.
190
191	- Last Page is SET: first_page equals (pageCount - 1) and
192	find_next_page_clear() will reach the CLEAR Page Guard. We blit the last
193	page to the screen. On the next iteration, page equals pageCount and
194	find_next_page_set() will reach the SET Page Guard. We still safely exit
195	from the update routine because the SET Page Guard position is greater
196	than pageCount.
197	*/
198
199	static inline void update_display_window_vosf(void)
200	{
201	int page = 0;
202	for (;;) {
203	const int first_page = find_next_page_set(page);
204	if (first_page >= mainBuffer.pageCount)
205	break;
206
207	page = find_next_page_clear(first_page);
208	PFLAG_CLEAR_RANGE(first_page, page);
209
210	// Make the dirty pages read-only again
211	const int32 offset = first_page << mainBuffer.pageBits;
212	const uint32 length = (page - first_page) << mainBuffer.pageBits;
213	mprotect((caddr_t)(mainBuffer.memStart + offset), length, PROT_READ);
214
215	// There is at least one line to update
216	const int y1 = mainBuffer.pageInfo[first_page].top;
217	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
218	const int height = y2 - y1 + 1;
219
220	const int bytes_per_row = VideoMonitor.bytes_per_row;
221	const int bytes_per_pixel = VideoMonitor.bytes_per_row / VideoMonitor.x;
222	int i, j;
223
224	// Check for first column from left and first column
225	// from right that have changed
226	int x1, x2, width;
227	if (depth == 1) {
228
229	x1 = VideoMonitor.x - 1;
230	for (j = y1; j <= y2; j++) {
231	uint8 * const p1 = &the_buffer[j * bytes_per_row];
232	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
233	for (i = 0; i < (x1>>3); i++) {
234	if (p1[i] != p2[i]) {
235	x1 = i << 3;
236	break;
237	}
238	}
239	}
240
241	x2 = x1;
242	for (j = y2; j >= y1; j--) {
243	uint8 * const p1 = &the_buffer[j * bytes_per_row];
244	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
245	for (i = (VideoMonitor.x>>3) - 1; i > (x2>>3); i--) {
246	if (p1[i] != p2[i]) {
247	x2 = (i << 3) + 7;
248	break;
249	}
250	}
251	}
252	width = x2 - x1 + 1;
253
254	// Update the_host_buffer and copy of the_buffer
255	i = y1 * bytes_per_row + (x1 >> 3);
256	for (j = y1; j <= y2; j++) {
257	Screen_blit(the_host_buffer + i, the_buffer + i, width >> 3);
258	memcpy(the_buffer_copy + i, the_buffer + i, width >> 3);
259	i += bytes_per_row;
260	}
261
262	} else {
263
264	x1 = VideoMonitor.x * bytes_per_pixel - 1;
265	for (j = y1; j <= y2; j++) {
266	uint8 * const p1 = &the_buffer[j * bytes_per_row];
267	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
268	for (i = 0; i < x1; i++) {
269	if (p1[i] != p2[i]) {
270	x1 = i;
271	break;
272	}
273	}
274	}
275	x1 /= bytes_per_pixel;
276
277	x2 = x1 * bytes_per_pixel;
278	for (j = y2; j >= y1; j--) {
279	uint8 * const p1 = &the_buffer[j * bytes_per_row];
280	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
281	for (i = VideoMonitor.x * bytes_per_pixel - 1; i > x2; i--) {
282	if (p1[i] != p2[i]) {
283	x2 = i;
284	break;
285	}
286	}
287	}
288	x2 /= bytes_per_pixel;
289	width = x2 - x1 + 1;
290
291	// Update the_host_buffer and copy of the_buffer
292	i = y1 * bytes_per_row + x1 * bytes_per_pixel;
293	for (j = y1; j <= y2; j++) {
294	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
295	memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
296	i += bytes_per_row;
297	}
298	}
299
300	if (have_shm)
301	XShmPutImage(x_display, the_win, the_gc, img, x1, y1, x1, y1, width, height, 0);
302	else
303	XPutImage(x_display, the_win, the_gc, img, x1, y1, x1, y1, width, height);
304	}
305	mainBuffer.dirty = false;
306	}
307
308
309	/*
310	* Update display for DGA mode and VOSF
311	* (only in Direct Addressing mode)
312	*/
313
314	#if REAL_ADDRESSING \|\| DIRECT_ADDRESSING
315	static inline void update_display_dga_vosf(void)
316	{
317	int page = 0;
318	for (;;) {
319	const int first_page = find_next_page_set(page);
320	if (first_page >= mainBuffer.pageCount)
321	break;
322
323	page = find_next_page_clear(first_page);
324	PFLAG_CLEAR_RANGE(first_page, page);
325
326	// Make the dirty pages read-only again
327	const int32 offset = first_page << mainBuffer.pageBits;
328	const uint32 length = (page - first_page) << mainBuffer.pageBits;
329	mprotect((caddr_t)(mainBuffer.memStart + offset), length, PROT_READ);
330
331	// I am sure that y2 >= y1 and depth != 1
332	const int y1 = mainBuffer.pageInfo[first_page].top;
333	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
334
335	const int bytes_per_row = VideoMonitor.bytes_per_row;
336	const int bytes_per_pixel = VideoMonitor.bytes_per_row / VideoMonitor.x;
337	int i, j;
338
339	// Check for first column from left and first column
340	// from right that have changed
341	int x1 = VideoMonitor.x * bytes_per_pixel - 1;
342	for (j = y1; j <= y2; j++) {
343	uint8 * const p1 = &the_buffer[j * bytes_per_row];
344	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
345	for (i = 0; i < x1; i++) {
346	if (p1[i] != p2[i]) {
347	x1 = i;
348	break;
349	}
350	}
351	}
352	x1 /= bytes_per_pixel;
353
354	int x2 = x1 * bytes_per_pixel;
355	for (j = y2; j >= y1; j--) {
356	uint8 * const p1 = &the_buffer[j * bytes_per_row];
357	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
358	for (i = VideoMonitor.x * bytes_per_pixel - 1; i > x2; i--) {
359	if (p1[i] != p2[i]) {
360	x2 = i;
361	break;
362	}
363	}
364	}
365	x2 /= bytes_per_pixel;
366
367	// Update the_host_buffer and copy of the_buffer
368	// There should be at least one pixel to copy
369	const int width = x2 - x1 + 1;
370	i = y1 * bytes_per_row + x1 * bytes_per_pixel;
371	for (j = y1; j <= y2; j++) {
372	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
373	memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
374	i += bytes_per_row;
375	}
376	}
377	mainBuffer.dirty = false;
378	}
379	#endif
380
381	#endif /* ENABLE_VOSF */
382
383	#endif /* VIDEO_VOSF_H */