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
static bool screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction)
{
        D(bug("screen_fault_handler: ADDR=0x%08X from IP=0x%08X\n", fault_address, fault_instruction));
        const uintptr addr = (uintptr)fault_address;
        
        /* 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 true;
        }
        
        /* 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 (fault_instruction != SIGSEGV_INVALID_PC)
                fprintf(stderr, " [IP=0x%08X]", fault_instruction);
        fprintf(stderr, "\n");
        return false;
}

/*
 *      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 = y1 * bytes_per_row, j;
                
                if (depth == 1) {

                        // Update the_host_buffer and copy of the_buffer
                        for (j = y1; j <= y2; j++) {
                                Screen_blit(the_host_buffer + i, the_buffer + i, VideoMonitor.x >> 3);
                                i += bytes_per_row;
                        }

                } else {

                        // Update the_host_buffer and copy of the_buffer
                        for (j = y1; j <= y2; j++) {
                                Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * VideoMonitor.x);
                                i += bytes_per_row;
                        }
                }

                if (have_shm)
                        XShmPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.x, height, 0);
                else
                        XPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.x, 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:	1.16
Committed:	2001-05-20T20:31:50Z (23 years, 1 month ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
CVS Tags:	snapshot-29052001, release-0_9-1
Changes since 1.15:	+9 -100 lines
Log Message:	- new and updated SIGSEGV support functions: + configure script cleanups + possible support for Direct Addressing / VOSF on other platforms
#	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	// Screen fault handler
47	static bool screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction)
48	{
49	D(bug("screen_fault_handler: ADDR=0x%08X from IP=0x%08X\n", fault_address, fault_instruction));
50	const uintptr addr = (uintptr)fault_address;
51
52	/* Someone attempted to write to the frame buffer. Make it writeable
53	* now so that the data could actually be written. It will be made
54	* read-only back in one of the screen update_*() functions.
55	*/
56	if ((addr >= mainBuffer.memStart) && (addr < mainBuffer.memEnd)) {
57	const int page = (addr - mainBuffer.memStart) >> mainBuffer.pageBits;
58	caddr_t page_ad = (caddr_t)(addr & ~(mainBuffer.pageSize - 1));
59	LOCK_VOSF;
60	PFLAG_SET(page);
61	mprotect(page_ad, mainBuffer.pageSize, PROT_READ \| PROT_WRITE);
62	mainBuffer.dirty = true;
63	UNLOCK_VOSF;
64	return true;
65	}
66
67	/* Otherwise, we don't know how to handle the fault, let it crash */
68	fprintf(stderr, "do_handle_screen_fault: unhandled address 0x%08X", addr);
69	if (fault_instruction != SIGSEGV_INVALID_PC)
70	fprintf(stderr, " [IP=0x%08X]", fault_instruction);
71	fprintf(stderr, "\n");
72	return false;
73	}
74
75	/*
76	* Update display for Windowed mode and VOSF
77	*/
78
79	// From video_blit.cpp
80	extern void (Screen_blit)(uint8 dest, const uint8 * source, uint32 length);
81	extern bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order);
82
83	/* How can we deal with array overrun conditions ?
84
85	The state of the framebuffer pages that have been touched are maintained
86	in the dirtyPages[] table. That table is (pageCount + 2) bytes long.
87
88	Terminology
89
90	"Last Page" denotes the pageCount-nth page, i.e. dirtyPages[pageCount - 1].
91	"CLEAR Page Guard" refers to the page following the Last Page but is always
92	in the CLEAR state. "SET Page Guard" refers to the page following the CLEAR
93	Page Guard but is always in the SET state.
94
95	Rough process
96
97	The update routines must determine which pages have to be blitted to the
98	screen. This job consists in finding the first_page that was touched.
99	i.e. find the next page that is SET. Then, finding how many pages were
100	touched starting from first_page. i.e. find the next page that is CLEAR.
101
102	There are two cases to check:
103
104	- Last Page is CLEAR: find_next_page_set() will reach the SET Page Guard
105	but it is beyond the valid pageCount value. Therefore, we exit from the
106	update routine.
107
108	- Last Page is SET: first_page equals (pageCount - 1) and
109	find_next_page_clear() will reach the CLEAR Page Guard. We blit the last
110	page to the screen. On the next iteration, page equals pageCount and
111	find_next_page_set() will reach the SET Page Guard. We still safely exit
112	from the update routine because the SET Page Guard position is greater
113	than pageCount.
114	*/
115
116	static inline void update_display_window_vosf(void)
117	{
118	int page = 0;
119	for (;;) {
120	const int first_page = find_next_page_set(page);
121	if (first_page >= mainBuffer.pageCount)
122	break;
123
124	page = find_next_page_clear(first_page);
125	PFLAG_CLEAR_RANGE(first_page, page);
126
127	// Make the dirty pages read-only again
128	const int32 offset = first_page << mainBuffer.pageBits;
129	const uint32 length = (page - first_page) << mainBuffer.pageBits;
130	mprotect((caddr_t)(mainBuffer.memStart + offset), length, PROT_READ);
131
132	// There is at least one line to update
133	const int y1 = mainBuffer.pageInfo[first_page].top;
134	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
135	const int height = y2 - y1 + 1;
136
137	const int bytes_per_row = VideoMonitor.bytes_per_row;
138	const int bytes_per_pixel = VideoMonitor.bytes_per_row / VideoMonitor.x;
139	int i = y1 * bytes_per_row, j;
140
141	if (depth == 1) {
142
143	// Update the_host_buffer and copy of the_buffer
144	for (j = y1; j <= y2; j++) {
145	Screen_blit(the_host_buffer + i, the_buffer + i, VideoMonitor.x >> 3);
146	i += bytes_per_row;
147	}
148
149	} else {
150
151	// Update the_host_buffer and copy of the_buffer
152	for (j = y1; j <= y2; j++) {
153	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * VideoMonitor.x);
154	i += bytes_per_row;
155	}
156	}
157
158	if (have_shm)
159	XShmPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.x, height, 0);
160	else
161	XPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.x, height);
162	}
163
164	mainBuffer.dirty = false;
165	}
166
167
168	/*
169	* Update display for DGA mode and VOSF
170	* (only in Direct Addressing mode)
171	*/
172
173	#if REAL_ADDRESSING \|\| DIRECT_ADDRESSING
174	static inline void update_display_dga_vosf(void)
175	{
176	int page = 0;
177	for (;;) {
178	const int first_page = find_next_page_set(page);
179	if (first_page >= mainBuffer.pageCount)
180	break;
181
182	page = find_next_page_clear(first_page);
183	PFLAG_CLEAR_RANGE(first_page, page);
184
185	// Make the dirty pages read-only again
186	const int32 offset = first_page << mainBuffer.pageBits;
187	const uint32 length = (page - first_page) << mainBuffer.pageBits;
188	mprotect((caddr_t)(mainBuffer.memStart + offset), length, PROT_READ);
189
190	// I am sure that y2 >= y1 and depth != 1
191	const int y1 = mainBuffer.pageInfo[first_page].top;
192	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
193
194	const int bytes_per_row = VideoMonitor.bytes_per_row;
195	const int bytes_per_pixel = VideoMonitor.bytes_per_row / VideoMonitor.x;
196	int i, j;
197
198	// Check for first column from left and first column
199	// from right that have changed
200	int x1 = VideoMonitor.x * bytes_per_pixel - 1;
201	for (j = y1; j <= y2; j++) {
202	uint8 * const p1 = &the_buffer[j * bytes_per_row];
203	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
204	for (i = 0; i < x1; i++) {
205	if (p1[i] != p2[i]) {
206	x1 = i;
207	break;
208	}
209	}
210	}
211	x1 /= bytes_per_pixel;
212
213	int x2 = x1 * bytes_per_pixel;
214	for (j = y2; j >= y1; j--) {
215	uint8 * const p1 = &the_buffer[j * bytes_per_row];
216	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
217	for (i = VideoMonitor.x * bytes_per_pixel - 1; i > x2; i--) {
218	if (p1[i] != p2[i]) {
219	x2 = i;
220	break;
221	}
222	}
223	}
224	x2 /= bytes_per_pixel;
225
226	// Update the_host_buffer and copy of the_buffer
227	// There should be at least one pixel to copy
228	const int width = x2 - x1 + 1;
229	i = y1 * bytes_per_row + x1 * bytes_per_pixel;
230	for (j = y1; j <= y2; j++) {
231	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
232	memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
233	i += bytes_per_row;
234	}
235	}
236	mainBuffer.dirty = false;
237	}
238	#endif
239
240	#endif /* ENABLE_VOSF */
241
242	#endif /* VIDEO_VOSF_H */