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

#include <fcntl.h>
#include <sys/mman.h>
#include "sigsegv.h"
#include "vm_alloc.h"

#ifdef ENABLE_MON
# include "mon.h"
#endif

// Variables for Video on SEGV support
static uint8 *the_host_buffer;  // Host frame buffer in VOSF mode
static uint32 the_buffer_size;  // Size of allocated the_buffer

struct ScreenPageInfo {
    int top, bottom;                    // Mapping between this virtual page and Mac scanlines
};

struct ScreenInfo {
    uintptr memBase;                    // Real start address 
    uintptr memStart;                   // Start address aligned to page boundary
    uintptr memEnd;                             // Address of one-past-the-end of the screen
    uint32 memLength;                   // Length of the memory addressed by the screen pages
    
    uint32 pageSize;                    // Size of a page
    int pageBits;                               // Shift count to get the page number
    uint32 pageCount;                   // Number of pages allocated to the screen
    
        bool dirty;                                     // Flag: set if the frame buffer was touched
    char * dirtyPages;                  // Table of flags set if page was altered
    ScreenPageInfo * pageInfo;  // Table of mappings page -> Mac scanlines
};

static ScreenInfo mainBuffer;

#define PFLAG_SET_VALUE                 0x00
#define PFLAG_CLEAR_VALUE               0x01
#define PFLAG_SET_VALUE_4               0x00000000
#define PFLAG_CLEAR_VALUE_4             0x01010101
#define PFLAG_SET(page)                 mainBuffer.dirtyPages[page] = PFLAG_SET_VALUE
#define PFLAG_CLEAR(page)               mainBuffer.dirtyPages[page] = PFLAG_CLEAR_VALUE
#define PFLAG_ISSET(page)               (mainBuffer.dirtyPages[page] == PFLAG_SET_VALUE)
#define PFLAG_ISCLEAR(page)             (mainBuffer.dirtyPages[page] != PFLAG_SET_VALUE)

#ifdef UNALIGNED_PROFITABLE
# define PFLAG_ISSET_4(page)    (*((uint32 *)(mainBuffer.dirtyPages + (page))) == PFLAG_SET_VALUE_4)
# define PFLAG_ISCLEAR_4(page)  (*((uint32 *)(mainBuffer.dirtyPages + (page))) == PFLAG_CLEAR_VALUE_4)
#else
# define PFLAG_ISSET_4(page) \
                PFLAG_ISSET(page  ) && PFLAG_ISSET(page+1) \
        &&      PFLAG_ISSET(page+2) && PFLAG_ISSET(page+3)
# define PFLAG_ISCLEAR_4(page) \
                PFLAG_ISCLEAR(page  ) && PFLAG_ISCLEAR(page+1) \
        &&      PFLAG_ISCLEAR(page+2) && PFLAG_ISCLEAR(page+3)
#endif

// Set the selected page range [ first_page, last_page [ into the SET state
#define PFLAG_SET_RANGE(first_page, last_page) \
        memset(mainBuffer.dirtyPages + (first_page), PFLAG_SET_VALUE, \
                (last_page) - (first_page))

// Set the selected page range [ first_page, last_page [ into the CLEAR state
#define PFLAG_CLEAR_RANGE(first_page, last_page) \
        memset(mainBuffer.dirtyPages + (first_page), PFLAG_CLEAR_VALUE, \
                (last_page) - (first_page))

#define PFLAG_SET_ALL do { \
        PFLAG_SET_RANGE(0, mainBuffer.pageCount); \
        mainBuffer.dirty = true; \
} while (0)

#define PFLAG_CLEAR_ALL do { \
        PFLAG_CLEAR_RANGE(0, mainBuffer.pageCount); \
        mainBuffer.dirty = false; \
} while (0)

// Set the following macro definition to 1 if your system
// provides a really fast strchr() implementation
//#define HAVE_FAST_STRCHR 0

static inline int find_next_page_set(int page)
{
#if HAVE_FAST_STRCHR
        char *match = strchr(mainBuffer.dirtyPages + page, PFLAG_SET_VALUE);
        return match ? match - mainBuffer.dirtyPages : mainBuffer.pageCount;
#else
        while (PFLAG_ISCLEAR_4(page))
                page += 4;
        while (PFLAG_ISCLEAR(page))
                page++;
        return page;
#endif
}

static inline int find_next_page_clear(int page)
{
#if HAVE_FAST_STRCHR
        char *match = strchr(mainBuffer.dirtyPages + page, PFLAG_CLEAR_VALUE);
        return match ? match - mainBuffer.dirtyPages : mainBuffer.pageCount;
#else
        while (PFLAG_ISSET_4(page))
                page += 4;
        while (PFLAG_ISSET(page))
                page++;
        return page;
#endif
}

#ifdef HAVE_PTHREADS
static pthread_mutex_t vosf_lock = PTHREAD_MUTEX_INITIALIZER;   // Mutex to protect frame buffer (dirtyPages in fact)
#define LOCK_VOSF pthread_mutex_lock(&vosf_lock);
#define UNLOCK_VOSF pthread_mutex_unlock(&vosf_lock);
#else
#define LOCK_VOSF
#define UNLOCK_VOSF
#endif

static int log_base_2(uint32 x)
{
        uint32 mask = 0x80000000;
        int l = 31;
        while (l >= 0 && (x & mask) == 0) {
                mask >>= 1;
                l--;
        }
        return l;
}

// Extend size to page boundary
static uint32 page_extend(uint32 size)
{
        const uint32 page_size = getpagesize();
        const uint32 page_mask = page_size - 1;
        return (size + page_mask) & ~page_mask;
}


/*
 *  Initialize mainBuffer structure
 */

static bool video_init_buffer(void)
{
        if (use_vosf) {
                const uint32 page_size  = getpagesize();
                const uint32 page_mask  = page_size - 1;
                
                mainBuffer.memBase      = (uintptr) the_buffer;
                // Round up frame buffer base to page boundary
                mainBuffer.memStart             = (uintptr)((((unsigned long) the_buffer) + page_mask) & ~page_mask);
                mainBuffer.memLength    = the_buffer_size;
                mainBuffer.memEnd       = mainBuffer.memStart + mainBuffer.memLength;

                mainBuffer.pageSize     = page_size;
                mainBuffer.pageCount    = (mainBuffer.memLength + page_mask)/mainBuffer.pageSize;
                mainBuffer.pageBits     = log_base_2(mainBuffer.pageSize);

                if (mainBuffer.dirtyPages) {
                        free(mainBuffer.dirtyPages);
                        mainBuffer.dirtyPages = NULL;
                }

                mainBuffer.dirtyPages = (char *) malloc(mainBuffer.pageCount + 2);

                if (mainBuffer.pageInfo) {
                        free(mainBuffer.pageInfo);
                        mainBuffer.pageInfo = NULL;
                }

                mainBuffer.pageInfo = (ScreenPageInfo *) malloc(mainBuffer.pageCount * sizeof(ScreenPageInfo));

                if ((mainBuffer.dirtyPages == NULL) || (mainBuffer.pageInfo == NULL))
                        return false;
                
                mainBuffer.dirty = false;

                PFLAG_CLEAR_ALL;
                // Safety net to insure the loops in the update routines will terminate
                // See "How can we deal with array overrun conditions ?" hereunder for further details
                PFLAG_CLEAR(mainBuffer.pageCount);
                PFLAG_SET(mainBuffer.pageCount+1);

                uint32 a = 0;
                for (int i = 0; i < mainBuffer.pageCount; i++) {
                        int y1 = a / VideoMonitor.mode.bytes_per_row;
                        if (y1 >= VideoMonitor.mode.y)
                                y1 = VideoMonitor.mode.y - 1;

                        int y2 = (a + mainBuffer.pageSize) / VideoMonitor.mode.bytes_per_row;
                        if (y2 >= VideoMonitor.mode.y)
                                y2 = VideoMonitor.mode.y - 1;

                        mainBuffer.pageInfo[i].top = y1;
                        mainBuffer.pageInfo[i].bottom = y2;

                        a += mainBuffer.pageSize;
                        if (a > mainBuffer.memLength)
                                a = mainBuffer.memLength;
                }
                
                // We can now write-protect the frame buffer
                if (vm_protect((char *)mainBuffer.memStart, mainBuffer.memLength, VM_PAGE_READ) != 0)
                        return false;
        }
        return true;
}


/*
 * 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 to. 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);
                LOCK_VOSF;
                PFLAG_SET(page);
                vm_protect((char *)page_ad, mainBuffer.pageSize, VM_PAGE_READ | VM_PAGE_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");
#if EMULATED_68K
        uaecptr nextpc;
        extern void m68k_dumpstate(uaecptr *nextpc);
        m68k_dumpstate(&nextpc);
#endif
#ifdef ENABLE_MON
        char *arg[4] = {"mon", "-m", "-r", NULL};
        mon(3, arg);
        QuitEmulator();
#endif
        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, video_depth mac_depth);

/*      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(driver_window *drv)
{
        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;
                vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_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.mode.bytes_per_row;
                const int bytes_per_pixel = VideoMonitor.mode.bytes_per_row / VideoMonitor.mode.x;
                int i = y1 * bytes_per_row, j;
                
                if (VideoMonitor.mode.depth == VDEPTH_1BIT) {

                        // 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.mode.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.mode.x);
                                i += bytes_per_row;
                        }
                }

                if (drv->have_shm)
                        XShmPutImage(x_display, drv->w, drv->gc, drv->img, 0, y1, 0, y1, VideoMonitor.mode.x, height, 0);
                else
                        XPutImage(x_display, drv->w, drv->gc, drv->img, 0, y1, 0, y1, VideoMonitor.mode.x, height);
        }
        mainBuffer.dirty = false;
}


/*
 *      Update display for DGA mode and VOSF
 *      (only in Real or 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;
                vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_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.mode.bytes_per_row;
                const int bytes_per_pixel = VideoMonitor.mode.bytes_per_row / VideoMonitor.mode.x;
                int i, j;
                
                // Check for first column from left and first column
                // from right that have changed
                int x1 = VideoMonitor.mode.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.mode.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:	1.22
Committed:	2001-07-01T14:38:03Z (23 years, 5 months ago) by cebix
Content type:	text/plain
Branch:	MAIN
Changes since 1.21:	+1 -1 lines
Log Message:	- sony.cpp/disk.cpp/cdrom.cpp use vector<> of drive_info objects instead of linked list - color depth switching updates slot ROM - video_x.cpp always supports 1-bit window modes - timer_create()/clock_gettime() are pulled from librt if present
#	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	#include <fcntl.h>
28	#include <sys/mman.h>
29	#include "sigsegv.h"
30	#include "vm_alloc.h"
31
32	#ifdef ENABLE_MON
33	# include "mon.h"
34	#endif
35
36	// Variables for Video on SEGV support
37	static uint8 *the_host_buffer; // Host frame buffer in VOSF mode
38	static uint32 the_buffer_size; // Size of allocated the_buffer
39
40	struct ScreenPageInfo {
41	int top, bottom; // Mapping between this virtual page and Mac scanlines
42	};
43
44	struct ScreenInfo {
45	uintptr memBase; // Real start address
46	uintptr memStart; // Start address aligned to page boundary
47	uintptr memEnd; // Address of one-past-the-end of the screen
48	uint32 memLength; // Length of the memory addressed by the screen pages
49
50	uint32 pageSize; // Size of a page
51	int pageBits; // Shift count to get the page number
52	uint32 pageCount; // Number of pages allocated to the screen
53
54	bool dirty; // Flag: set if the frame buffer was touched
55	char * dirtyPages; // Table of flags set if page was altered
56	ScreenPageInfo * pageInfo; // Table of mappings page -> Mac scanlines
57	};
58
59	static ScreenInfo mainBuffer;
60
61	#define PFLAG_SET_VALUE 0x00
62	#define PFLAG_CLEAR_VALUE 0x01
63	#define PFLAG_SET_VALUE_4 0x00000000
64	#define PFLAG_CLEAR_VALUE_4 0x01010101
65	#define PFLAG_SET(page) mainBuffer.dirtyPages[page] = PFLAG_SET_VALUE
66	#define PFLAG_CLEAR(page) mainBuffer.dirtyPages[page] = PFLAG_CLEAR_VALUE
67	#define PFLAG_ISSET(page) (mainBuffer.dirtyPages[page] == PFLAG_SET_VALUE)
68	#define PFLAG_ISCLEAR(page) (mainBuffer.dirtyPages[page] != PFLAG_SET_VALUE)
69
70	#ifdef UNALIGNED_PROFITABLE
71	# define PFLAG_ISSET_4(page) (((uint32 )(mainBuffer.dirtyPages + (page))) == PFLAG_SET_VALUE_4)
72	# define PFLAG_ISCLEAR_4(page) (((uint32 )(mainBuffer.dirtyPages + (page))) == PFLAG_CLEAR_VALUE_4)
73	#else
74	# define PFLAG_ISSET_4(page) \
75	PFLAG_ISSET(page ) && PFLAG_ISSET(page+1) \
76	&& PFLAG_ISSET(page+2) && PFLAG_ISSET(page+3)
77	# define PFLAG_ISCLEAR_4(page) \
78	PFLAG_ISCLEAR(page ) && PFLAG_ISCLEAR(page+1) \
79	&& PFLAG_ISCLEAR(page+2) && PFLAG_ISCLEAR(page+3)
80	#endif
81
82	// Set the selected page range [ first_page, last_page [ into the SET state
83	#define PFLAG_SET_RANGE(first_page, last_page) \
84	memset(mainBuffer.dirtyPages + (first_page), PFLAG_SET_VALUE, \
85	(last_page) - (first_page))
86
87	// Set the selected page range [ first_page, last_page [ into the CLEAR state
88	#define PFLAG_CLEAR_RANGE(first_page, last_page) \
89	memset(mainBuffer.dirtyPages + (first_page), PFLAG_CLEAR_VALUE, \
90	(last_page) - (first_page))
91
92	#define PFLAG_SET_ALL do { \
93	PFLAG_SET_RANGE(0, mainBuffer.pageCount); \
94	mainBuffer.dirty = true; \
95	} while (0)
96
97	#define PFLAG_CLEAR_ALL do { \
98	PFLAG_CLEAR_RANGE(0, mainBuffer.pageCount); \
99	mainBuffer.dirty = false; \
100	} while (0)
101
102	// Set the following macro definition to 1 if your system
103	// provides a really fast strchr() implementation
104	//#define HAVE_FAST_STRCHR 0
105
106	static inline int find_next_page_set(int page)
107	{
108	#if HAVE_FAST_STRCHR
109	char *match = strchr(mainBuffer.dirtyPages + page, PFLAG_SET_VALUE);
110	return match ? match - mainBuffer.dirtyPages : mainBuffer.pageCount;
111	#else
112	while (PFLAG_ISCLEAR_4(page))
113	page += 4;
114	while (PFLAG_ISCLEAR(page))
115	page++;
116	return page;
117	#endif
118	}
119
120	static inline int find_next_page_clear(int page)
121	{
122	#if HAVE_FAST_STRCHR
123	char *match = strchr(mainBuffer.dirtyPages + page, PFLAG_CLEAR_VALUE);
124	return match ? match - mainBuffer.dirtyPages : mainBuffer.pageCount;
125	#else
126	while (PFLAG_ISSET_4(page))
127	page += 4;
128	while (PFLAG_ISSET(page))
129	page++;
130	return page;
131	#endif
132	}
133
134	#ifdef HAVE_PTHREADS
135	static pthread_mutex_t vosf_lock = PTHREAD_MUTEX_INITIALIZER; // Mutex to protect frame buffer (dirtyPages in fact)
136	#define LOCK_VOSF pthread_mutex_lock(&vosf_lock);
137	#define UNLOCK_VOSF pthread_mutex_unlock(&vosf_lock);
138	#else
139	#define LOCK_VOSF
140	#define UNLOCK_VOSF
141	#endif
142
143	static int log_base_2(uint32 x)
144	{
145	uint32 mask = 0x80000000;
146	int l = 31;
147	while (l >= 0 && (x & mask) == 0) {
148	mask >>= 1;
149	l--;
150	}
151	return l;
152	}
153
154	// Extend size to page boundary
155	static uint32 page_extend(uint32 size)
156	{
157	const uint32 page_size = getpagesize();
158	const uint32 page_mask = page_size - 1;
159	return (size + page_mask) & ~page_mask;
160	}
161
162
163	/*
164	* Initialize mainBuffer structure
165	*/
166
167	static bool video_init_buffer(void)
168	{
169	if (use_vosf) {
170	const uint32 page_size = getpagesize();
171	const uint32 page_mask = page_size - 1;
172
173	mainBuffer.memBase = (uintptr) the_buffer;
174	// Round up frame buffer base to page boundary
175	mainBuffer.memStart = (uintptr)((((unsigned long) the_buffer) + page_mask) & ~page_mask);
176	mainBuffer.memLength = the_buffer_size;
177	mainBuffer.memEnd = mainBuffer.memStart + mainBuffer.memLength;
178
179	mainBuffer.pageSize = page_size;
180	mainBuffer.pageCount = (mainBuffer.memLength + page_mask)/mainBuffer.pageSize;
181	mainBuffer.pageBits = log_base_2(mainBuffer.pageSize);
182
183	if (mainBuffer.dirtyPages) {
184	free(mainBuffer.dirtyPages);
185	mainBuffer.dirtyPages = NULL;
186	}
187
188	mainBuffer.dirtyPages = (char *) malloc(mainBuffer.pageCount + 2);
189
190	if (mainBuffer.pageInfo) {
191	free(mainBuffer.pageInfo);
192	mainBuffer.pageInfo = NULL;
193	}
194
195	mainBuffer.pageInfo = (ScreenPageInfo ) malloc(mainBuffer.pageCount sizeof(ScreenPageInfo));
196
197	if ((mainBuffer.dirtyPages == NULL) \|\| (mainBuffer.pageInfo == NULL))
198	return false;
199
200	mainBuffer.dirty = false;
201
202	PFLAG_CLEAR_ALL;
203	// Safety net to insure the loops in the update routines will terminate
204	// See "How can we deal with array overrun conditions ?" hereunder for further details
205	PFLAG_CLEAR(mainBuffer.pageCount);
206	PFLAG_SET(mainBuffer.pageCount+1);
207
208	uint32 a = 0;
209	for (int i = 0; i < mainBuffer.pageCount; i++) {
210	int y1 = a / VideoMonitor.mode.bytes_per_row;
211	if (y1 >= VideoMonitor.mode.y)
212	y1 = VideoMonitor.mode.y - 1;
213
214	int y2 = (a + mainBuffer.pageSize) / VideoMonitor.mode.bytes_per_row;
215	if (y2 >= VideoMonitor.mode.y)
216	y2 = VideoMonitor.mode.y - 1;
217
218	mainBuffer.pageInfo[i].top = y1;
219	mainBuffer.pageInfo[i].bottom = y2;
220
221	a += mainBuffer.pageSize;
222	if (a > mainBuffer.memLength)
223	a = mainBuffer.memLength;
224	}
225
226	// We can now write-protect the frame buffer
227	if (vm_protect((char *)mainBuffer.memStart, mainBuffer.memLength, VM_PAGE_READ) != 0)
228	return false;
229	}
230	return true;
231	}
232
233
234	/*
235	* Screen fault handler
236	*/
237
238	static bool screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction)
239	{
240	D(bug("screen_fault_handler: ADDR=0x%08X from IP=0x%08X\n", fault_address, fault_instruction));
241	const uintptr addr = (uintptr)fault_address;
242
243	/* Someone attempted to write to the frame buffer. Make it writeable
244	* now so that the data could actually be written to. It will be made
245	* read-only back in one of the screen update_*() functions.
246	*/
247	if ((addr >= mainBuffer.memStart) && (addr < mainBuffer.memEnd)) {
248	const int page = (addr - mainBuffer.memStart) >> mainBuffer.pageBits;
249	caddr_t page_ad = (caddr_t)(addr & -mainBuffer.pageSize);
250	LOCK_VOSF;
251	PFLAG_SET(page);
252	vm_protect((char *)page_ad, mainBuffer.pageSize, VM_PAGE_READ \| VM_PAGE_WRITE);
253	mainBuffer.dirty = true;
254	UNLOCK_VOSF;
255	return true;
256	}
257
258	/* Otherwise, we don't know how to handle the fault, let it crash */
259	fprintf(stderr, "do_handle_screen_fault: unhandled address 0x%08X", addr);
260	if (fault_instruction != SIGSEGV_INVALID_PC)
261	fprintf(stderr, " [IP=0x%08X]", fault_instruction);
262	fprintf(stderr, "\n");
263	#if EMULATED_68K
264	uaecptr nextpc;
265	extern void m68k_dumpstate(uaecptr *nextpc);
266	m68k_dumpstate(&nextpc);
267	#endif
268	#ifdef ENABLE_MON
269	char *arg[4] = {"mon", "-m", "-r", NULL};
270	mon(3, arg);
271	QuitEmulator();
272	#endif
273	return false;
274	}
275
276
277	/*
278	* Update display for Windowed mode and VOSF
279	*/
280
281	// From video_blit.cpp
282	extern void (Screen_blit)(uint8 dest, const uint8 * source, uint32 length);
283	extern bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order, video_depth mac_depth);
284
285	/* How can we deal with array overrun conditions ?
286
287	The state of the framebuffer pages that have been touched are maintained
288	in the dirtyPages[] table. That table is (pageCount + 2) bytes long.
289
290	Terminology
291
292	"Last Page" denotes the pageCount-nth page, i.e. dirtyPages[pageCount - 1].
293	"CLEAR Page Guard" refers to the page following the Last Page but is always
294	in the CLEAR state. "SET Page Guard" refers to the page following the CLEAR
295	Page Guard but is always in the SET state.
296
297	Rough process
298
299	The update routines must determine which pages have to be blitted to the
300	screen. This job consists in finding the first_page that was touched.
301	i.e. find the next page that is SET. Then, finding how many pages were
302	touched starting from first_page. i.e. find the next page that is CLEAR.
303
304	There are two cases to check:
305
306	- Last Page is CLEAR: find_next_page_set() will reach the SET Page Guard
307	but it is beyond the valid pageCount value. Therefore, we exit from the
308	update routine.
309
310	- Last Page is SET: first_page equals (pageCount - 1) and
311	find_next_page_clear() will reach the CLEAR Page Guard. We blit the last
312	page to the screen. On the next iteration, page equals pageCount and
313	find_next_page_set() will reach the SET Page Guard. We still safely exit
314	from the update routine because the SET Page Guard position is greater
315	than pageCount.
316	*/
317
318	static inline void update_display_window_vosf(driver_window *drv)
319	{
320	int page = 0;
321	for (;;) {
322	const int first_page = find_next_page_set(page);
323	if (first_page >= mainBuffer.pageCount)
324	break;
325
326	page = find_next_page_clear(first_page);
327	PFLAG_CLEAR_RANGE(first_page, page);
328
329	// Make the dirty pages read-only again
330	const int32 offset = first_page << mainBuffer.pageBits;
331	const uint32 length = (page - first_page) << mainBuffer.pageBits;
332	vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_READ);
333
334	// There is at least one line to update
335	const int y1 = mainBuffer.pageInfo[first_page].top;
336	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
337	const int height = y2 - y1 + 1;
338
339	const int bytes_per_row = VideoMonitor.mode.bytes_per_row;
340	const int bytes_per_pixel = VideoMonitor.mode.bytes_per_row / VideoMonitor.mode.x;
341	int i = y1 * bytes_per_row, j;
342
343	if (VideoMonitor.mode.depth == VDEPTH_1BIT) {
344
345	// Update the_host_buffer and copy of the_buffer
346	for (j = y1; j <= y2; j++) {
347	Screen_blit(the_host_buffer + i, the_buffer + i, VideoMonitor.mode.x >> 3);
348	i += bytes_per_row;
349	}
350
351	} else {
352
353	// Update the_host_buffer and copy of the_buffer
354	for (j = y1; j <= y2; j++) {
355	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * VideoMonitor.mode.x);
356	i += bytes_per_row;
357	}
358	}
359
360	if (drv->have_shm)
361	XShmPutImage(x_display, drv->w, drv->gc, drv->img, 0, y1, 0, y1, VideoMonitor.mode.x, height, 0);
362	else
363	XPutImage(x_display, drv->w, drv->gc, drv->img, 0, y1, 0, y1, VideoMonitor.mode.x, height);
364	}
365	mainBuffer.dirty = false;
366	}
367
368
369	/*
370	* Update display for DGA mode and VOSF
371	* (only in Real or Direct Addressing mode)
372	*/
373
374	#if REAL_ADDRESSING \|\| DIRECT_ADDRESSING
375	static inline void update_display_dga_vosf(void)
376	{
377	int page = 0;
378	for (;;) {
379	const int first_page = find_next_page_set(page);
380	if (first_page >= mainBuffer.pageCount)
381	break;
382
383	page = find_next_page_clear(first_page);
384	PFLAG_CLEAR_RANGE(first_page, page);
385
386	// Make the dirty pages read-only again
387	const int32 offset = first_page << mainBuffer.pageBits;
388	const uint32 length = (page - first_page) << mainBuffer.pageBits;
389	vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_READ);
390
391	// I am sure that y2 >= y1 and depth != 1
392	const int y1 = mainBuffer.pageInfo[first_page].top;
393	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
394
395	const int bytes_per_row = VideoMonitor.mode.bytes_per_row;
396	const int bytes_per_pixel = VideoMonitor.mode.bytes_per_row / VideoMonitor.mode.x;
397	int i, j;
398
399	// Check for first column from left and first column
400	// from right that have changed
401	int x1 = VideoMonitor.mode.x * bytes_per_pixel - 1;
402	for (j = y1; j <= y2; j++) {
403	uint8 * const p1 = &the_buffer[j * bytes_per_row];
404	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
405	for (i = 0; i < x1; i++) {
406	if (p1[i] != p2[i]) {
407	x1 = i;
408	break;
409	}
410	}
411	}
412	x1 /= bytes_per_pixel;
413
414	int x2 = x1 * bytes_per_pixel;
415	for (j = y2; j >= y1; j--) {
416	uint8 * const p1 = &the_buffer[j * bytes_per_row];
417	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
418	for (i = VideoMonitor.mode.x * bytes_per_pixel - 1; i > x2; i--) {
419	if (p1[i] != p2[i]) {
420	x2 = i;
421	break;
422	}
423	}
424	}
425	x2 /= bytes_per_pixel;
426
427	// Update the_host_buffer and copy of the_buffer
428	// There should be at least one pixel to copy
429	const int width = x2 - x1 + 1;
430	i = y1 * bytes_per_row + x1 * bytes_per_pixel;
431	for (j = y1; j <= y2; j++) {
432	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
433	memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
434	i += bytes_per_row;
435	}
436	}
437	mainBuffer.dirty = false;
438	}
439	#endif
440
441	#endif /* ENABLE_VOSF */
442
443	#endif /* VIDEO_VOSF_H */