src/Unix/video_vosf.h

/*
 *  video_vosf.h - Video/graphics emulation, video on SEGV signals support
 *
 *  Basilisk II (C) 1997-2002 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 must be #include'd only in video_x.cpp
#ifdef ENABLE_VOSF

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

// Glue for SheepShaver and BasiliskII
#if POWERPC_ROM
#define X11_MONITOR_INIT                /* nothing */
#define VIDEO_DRV_INIT                  /* nothing */
#define VIDEO_DRV_WINDOW                the_win
#define VIDEO_DRV_GC                    the_gc
#define VIDEO_DRV_IMAGE                 img
#define VIDEO_DRV_HAVE_SHM              have_shm
#define VIDEO_MODE_INIT                 VideoInfo const & mode = VModes[cur_mode]
#define VIDEO_MODE_ROW_BYTES    mode.viRowBytes
#define VIDEO_MODE_X                    mode.viXsize
#define VIDEO_MODE_Y                    mode.viYsize
#define VIDEO_MODE_DEPTH                mode.viAppleMode
enum {
  VIDEO_DEPTH_1BIT = APPLE_1_BIT,
  VIDEO_DEPTH_2BIT = APPLE_2_BIT,
  VIDEO_DEPTH_4BIT = APPLE_4_BIT,
  VIDEO_DEPTH_8BIT = APPLE_8_BIT,
  VIDEO_DEPTH_16BIT = APPLE_16_BIT,
  VIDEO_DEPTH_32BIT = APPLE_32_BIT
};
#else
#define X11_MONITOR_INIT                X11_monitor_desc &monitor
#define VIDEO_DRV_INIT                  driver_window *drv
#define VIDEO_DRV_WINDOW                drv->w
#define VIDEO_DRV_GC                    drv->gc
#define VIDEO_DRV_IMAGE                 drv->img
#define VIDEO_DRV_HAVE_SHM              drv->have_shm
#define VIDEO_MODE_INIT                 video_mode const & mode = drv->monitor.get_current_mode();
#define VIDEO_MODE_ROW_BYTES    mode.bytes_per_row
#define VIDEO_MODE_X                    mode.x
#define VIDEO_MODE_Y                    mode.y
#define VIDEO_MODE_DEPTH                (int)mode.depth
enum {
  VIDEO_DEPTH_1BIT = VDEPTH_1BIT,
  VIDEO_DEPTH_2BIT = VDEPTH_2BIT,
  VIDEO_DEPTH_4BIT = VDEPTH_4BIT,
  VIDEO_DEPTH_8BIT = VDEPTH_8BIT,
  VIDEO_DEPTH_16BIT = VDEPTH_16BIT,
  VIDEO_DEPTH_32BIT = VDEPTH_32BIT
};
#endif

// Variables for Video on SEGV support
static uint8 *the_host_buffer;  // Host frame buffer in VOSF mode

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

struct ScreenInfo {
    uintptr memStart;                   // Start address aligned to page boundary
    uint32 memLength;                   // Length of the memory addressed by the screen pages
    
    uintptr 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 the VOSF system (mainBuffer structure, SIGSEGV handler)
 */

static bool video_vosf_init(X11_MONITOR_INIT)
{
        VIDEO_MODE_INIT;

        const uintptr page_size = getpagesize();
        const uintptr page_mask = page_size - 1;
        
        // Round up frame buffer base to page boundary
        mainBuffer.memStart = (((uintptr) the_buffer) + page_mask) & ~page_mask;
        
        // The frame buffer size shall already be aligned to page boundary (use page_extend)
        mainBuffer.memLength = the_buffer_size;
        
        mainBuffer.pageSize = page_size;
        mainBuffer.pageBits = log_base_2(mainBuffer.pageSize);
        mainBuffer.pageCount =  (mainBuffer.memLength + page_mask)/mainBuffer.pageSize;
        
        // The "2" more bytes requested are a 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.
        mainBuffer.dirtyPages = (char *) malloc(mainBuffer.pageCount + 2);
        if (mainBuffer.dirtyPages == NULL)
                return false;
                
        PFLAG_CLEAR_ALL;
        PFLAG_CLEAR(mainBuffer.pageCount);
        PFLAG_SET(mainBuffer.pageCount+1);
        
        // Allocate and fill in pageInfo with start and end (inclusive) row in number of bytes
        mainBuffer.pageInfo = (ScreenPageInfo *) malloc(mainBuffer.pageCount * sizeof(ScreenPageInfo));
        if (mainBuffer.pageInfo == NULL)
                return false;
        
        uint32 a = 0;
        for (unsigned i = 0; i < mainBuffer.pageCount; i++) {
                unsigned y1 = a / VIDEO_MODE_ROW_BYTES;
                if (y1 >= VIDEO_MODE_Y)
                        y1 = VIDEO_MODE_Y - 1;

                unsigned y2 = (a + mainBuffer.pageSize) / VIDEO_MODE_ROW_BYTES;
                if (y2 >= VIDEO_MODE_Y)
                        y2 = VIDEO_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;
        
        // The frame buffer is sane, i.e. there is no write to it yet
        mainBuffer.dirty = false;
        return true;
}


/*
 * Deinitialize VOSF system
 */

static void video_vosf_exit(void)
{
        if (mainBuffer.pageInfo) {
                free(mainBuffer.pageInfo);
                mainBuffer.pageInfo = NULL;
        }
        if (mainBuffer.dirtyPages) {
                free(mainBuffer.dirtyPages);
                mainBuffer.dirtyPages = NULL;
        }
}


/*
 * Screen fault handler
 */

bool Screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t 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 (((uintptr)addr - mainBuffer.memStart) < mainBuffer.memLength) {
                const int page  = ((uintptr)addr - mainBuffer.memStart) >> mainBuffer.pageBits;
                LOCK_VOSF;
                PFLAG_SET(page);
                vm_protect((char *)(addr & -mainBuffer.pageSize), 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 */
        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, int mac_depth);
extern uint32 ExpandMap[256];

/*      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(VIDEO_DRV_INIT)
{
        VIDEO_MODE_INIT;

        int page = 0;
        for (;;) {
                const unsigned 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;
                
                if (VIDEO_MODE_DEPTH < VIDEO_DEPTH_8BIT) {

                        // Update the_host_buffer and copy of the_buffer
                        const int src_bytes_per_row = VIDEO_MODE_ROW_BYTES;
                        const int dst_bytes_per_row = VIDEO_DRV_IMAGE->bytes_per_line;
                        const int pixels_per_byte = VIDEO_MODE_X / src_bytes_per_row;
                        int i1 = y1 * src_bytes_per_row, i2 = y1 * dst_bytes_per_row, j;
                        for (j = y1; j <= y2; j++) {
                                Screen_blit(the_host_buffer + i2, the_buffer + i1, VIDEO_MODE_X / pixels_per_byte);
                                i1 += src_bytes_per_row;
                                i2 += dst_bytes_per_row;
                        }

                } else {

                        // Update the_host_buffer and copy of the_buffer
                        const int src_bytes_per_row = VIDEO_MODE_ROW_BYTES;
                        const int dst_bytes_per_row = VIDEO_DRV_IMAGE->bytes_per_line;
                        const int bytes_per_pixel = src_bytes_per_row / VIDEO_MODE_X;
                        int i1 = y1 * src_bytes_per_row, i2 = y1 * dst_bytes_per_row, j;
                        for (j = y1; j <= y2; j++) {
                                Screen_blit(the_host_buffer + i2, the_buffer + i1, bytes_per_pixel * VIDEO_MODE_X);
                                i1 += src_bytes_per_row;
                                i2 += dst_bytes_per_row;
                        }
                }

                if (VIDEO_DRV_HAVE_SHM)
                        XShmPutImage(x_display, VIDEO_DRV_WINDOW, VIDEO_DRV_GC, VIDEO_DRV_IMAGE, 0, y1, 0, y1, VIDEO_MODE_X, height, 0);
                else
                        XPutImage(x_display, VIDEO_DRV_WINDOW, VIDEO_DRV_GC, VIDEO_DRV_IMAGE, 0, y1, 0, y1, VIDEO_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)
{
        VIDEO_MODE_INIT;

        int page = 0;
        for (;;) {
                const unsigned 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 = VIDEO_MODE_ROW_BYTES;
                const int bytes_per_pixel = VIDEO_MODE_ROW_BYTES / VIDEO_MODE_X;
                int i, j;
                
                // Check for first column from left and first column
                // from right that have changed
                int x1 = VIDEO_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 = VIDEO_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:	1.34
Committed:	2003-09-29T07:02:58Z (21 years, 1 month ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
Changes since 1.33:	+1 -12 lines
Log Message:	New SIGSEGV API so that skip-instruction requests are more explicit. Yes, that's api change, but that's cooler now for SheepShaver. ;-)
#	Content
1	/*
2	* video_vosf.h - Video/graphics emulation, video on SEGV signals support
3	*
4	* Basilisk II (C) 1997-2002 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 must be #include'd only 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	// Glue for SheepShaver and BasiliskII
33	#if POWERPC_ROM
34	#define X11_MONITOR_INIT /* nothing */
35	#define VIDEO_DRV_INIT /* nothing */
36	#define VIDEO_DRV_WINDOW the_win
37	#define VIDEO_DRV_GC the_gc
38	#define VIDEO_DRV_IMAGE img
39	#define VIDEO_DRV_HAVE_SHM have_shm
40	#define VIDEO_MODE_INIT VideoInfo const & mode = VModes[cur_mode]
41	#define VIDEO_MODE_ROW_BYTES mode.viRowBytes
42	#define VIDEO_MODE_X mode.viXsize
43	#define VIDEO_MODE_Y mode.viYsize
44	#define VIDEO_MODE_DEPTH mode.viAppleMode
45	enum {
46	VIDEO_DEPTH_1BIT = APPLE_1_BIT,
47	VIDEO_DEPTH_2BIT = APPLE_2_BIT,
48	VIDEO_DEPTH_4BIT = APPLE_4_BIT,
49	VIDEO_DEPTH_8BIT = APPLE_8_BIT,
50	VIDEO_DEPTH_16BIT = APPLE_16_BIT,
51	VIDEO_DEPTH_32BIT = APPLE_32_BIT
52	};
53	#else
54	#define X11_MONITOR_INIT X11_monitor_desc &monitor
55	#define VIDEO_DRV_INIT driver_window *drv
56	#define VIDEO_DRV_WINDOW drv->w
57	#define VIDEO_DRV_GC drv->gc
58	#define VIDEO_DRV_IMAGE drv->img
59	#define VIDEO_DRV_HAVE_SHM drv->have_shm
60	#define VIDEO_MODE_INIT video_mode const & mode = drv->monitor.get_current_mode();
61	#define VIDEO_MODE_ROW_BYTES mode.bytes_per_row
62	#define VIDEO_MODE_X mode.x
63	#define VIDEO_MODE_Y mode.y
64	#define VIDEO_MODE_DEPTH (int)mode.depth
65	enum {
66	VIDEO_DEPTH_1BIT = VDEPTH_1BIT,
67	VIDEO_DEPTH_2BIT = VDEPTH_2BIT,
68	VIDEO_DEPTH_4BIT = VDEPTH_4BIT,
69	VIDEO_DEPTH_8BIT = VDEPTH_8BIT,
70	VIDEO_DEPTH_16BIT = VDEPTH_16BIT,
71	VIDEO_DEPTH_32BIT = VDEPTH_32BIT
72	};
73	#endif
74
75	// Variables for Video on SEGV support
76	static uint8 *the_host_buffer; // Host frame buffer in VOSF mode
77
78	struct ScreenPageInfo {
79	int top, bottom; // Mapping between this virtual page and Mac scanlines
80	};
81
82	struct ScreenInfo {
83	uintptr memStart; // Start address aligned to page boundary
84	uint32 memLength; // Length of the memory addressed by the screen pages
85
86	uintptr pageSize; // Size of a page
87	int pageBits; // Shift count to get the page number
88	uint32 pageCount; // Number of pages allocated to the screen
89
90	bool dirty; // Flag: set if the frame buffer was touched
91	char * dirtyPages; // Table of flags set if page was altered
92	ScreenPageInfo * pageInfo; // Table of mappings page -> Mac scanlines
93	};
94
95	static ScreenInfo mainBuffer;
96
97	#define PFLAG_SET_VALUE 0x00
98	#define PFLAG_CLEAR_VALUE 0x01
99	#define PFLAG_SET_VALUE_4 0x00000000
100	#define PFLAG_CLEAR_VALUE_4 0x01010101
101	#define PFLAG_SET(page) mainBuffer.dirtyPages[page] = PFLAG_SET_VALUE
102	#define PFLAG_CLEAR(page) mainBuffer.dirtyPages[page] = PFLAG_CLEAR_VALUE
103	#define PFLAG_ISSET(page) (mainBuffer.dirtyPages[page] == PFLAG_SET_VALUE)
104	#define PFLAG_ISCLEAR(page) (mainBuffer.dirtyPages[page] != PFLAG_SET_VALUE)
105
106	#ifdef UNALIGNED_PROFITABLE
107	# define PFLAG_ISSET_4(page) (((uint32 )(mainBuffer.dirtyPages + (page))) == PFLAG_SET_VALUE_4)
108	# define PFLAG_ISCLEAR_4(page) (((uint32 )(mainBuffer.dirtyPages + (page))) == PFLAG_CLEAR_VALUE_4)
109	#else
110	# define PFLAG_ISSET_4(page) \
111	PFLAG_ISSET(page ) && PFLAG_ISSET(page+1) \
112	&& PFLAG_ISSET(page+2) && PFLAG_ISSET(page+3)
113	# define PFLAG_ISCLEAR_4(page) \
114	PFLAG_ISCLEAR(page ) && PFLAG_ISCLEAR(page+1) \
115	&& PFLAG_ISCLEAR(page+2) && PFLAG_ISCLEAR(page+3)
116	#endif
117
118	// Set the selected page range [ first_page, last_page [ into the SET state
119	#define PFLAG_SET_RANGE(first_page, last_page) \
120	memset(mainBuffer.dirtyPages + (first_page), PFLAG_SET_VALUE, \
121	(last_page) - (first_page))
122
123	// Set the selected page range [ first_page, last_page [ into the CLEAR state
124	#define PFLAG_CLEAR_RANGE(first_page, last_page) \
125	memset(mainBuffer.dirtyPages + (first_page), PFLAG_CLEAR_VALUE, \
126	(last_page) - (first_page))
127
128	#define PFLAG_SET_ALL do { \
129	PFLAG_SET_RANGE(0, mainBuffer.pageCount); \
130	mainBuffer.dirty = true; \
131	} while (0)
132
133	#define PFLAG_CLEAR_ALL do { \
134	PFLAG_CLEAR_RANGE(0, mainBuffer.pageCount); \
135	mainBuffer.dirty = false; \
136	} while (0)
137
138	// Set the following macro definition to 1 if your system
139	// provides a really fast strchr() implementation
140	//#define HAVE_FAST_STRCHR 0
141
142	static inline int find_next_page_set(int page)
143	{
144	#if HAVE_FAST_STRCHR
145	char *match = strchr(mainBuffer.dirtyPages + page, PFLAG_SET_VALUE);
146	return match ? match - mainBuffer.dirtyPages : mainBuffer.pageCount;
147	#else
148	while (PFLAG_ISCLEAR_4(page))
149	page += 4;
150	while (PFLAG_ISCLEAR(page))
151	page++;
152	return page;
153	#endif
154	}
155
156	static inline int find_next_page_clear(int page)
157	{
158	#if HAVE_FAST_STRCHR
159	char *match = strchr(mainBuffer.dirtyPages + page, PFLAG_CLEAR_VALUE);
160	return match ? match - mainBuffer.dirtyPages : mainBuffer.pageCount;
161	#else
162	while (PFLAG_ISSET_4(page))
163	page += 4;
164	while (PFLAG_ISSET(page))
165	page++;
166	return page;
167	#endif
168	}
169
170	#ifdef HAVE_PTHREADS
171	static pthread_mutex_t vosf_lock = PTHREAD_MUTEX_INITIALIZER; // Mutex to protect frame buffer (dirtyPages in fact)
172	#define LOCK_VOSF pthread_mutex_lock(&vosf_lock);
173	#define UNLOCK_VOSF pthread_mutex_unlock(&vosf_lock);
174	#else
175	#define LOCK_VOSF
176	#define UNLOCK_VOSF
177	#endif
178
179	static int log_base_2(uint32 x)
180	{
181	uint32 mask = 0x80000000;
182	int l = 31;
183	while (l >= 0 && (x & mask) == 0) {
184	mask >>= 1;
185	l--;
186	}
187	return l;
188	}
189
190	// Extend size to page boundary
191	static uint32 page_extend(uint32 size)
192	{
193	const uint32 page_size = getpagesize();
194	const uint32 page_mask = page_size - 1;
195	return (size + page_mask) & ~page_mask;
196	}
197
198
199	/*
200	* Initialize the VOSF system (mainBuffer structure, SIGSEGV handler)
201	*/
202
203	static bool video_vosf_init(X11_MONITOR_INIT)
204	{
205	VIDEO_MODE_INIT;
206
207	const uintptr page_size = getpagesize();
208	const uintptr page_mask = page_size - 1;
209
210	// Round up frame buffer base to page boundary
211	mainBuffer.memStart = (((uintptr) the_buffer) + page_mask) & ~page_mask;
212
213	// The frame buffer size shall already be aligned to page boundary (use page_extend)
214	mainBuffer.memLength = the_buffer_size;
215
216	mainBuffer.pageSize = page_size;
217	mainBuffer.pageBits = log_base_2(mainBuffer.pageSize);
218	mainBuffer.pageCount = (mainBuffer.memLength + page_mask)/mainBuffer.pageSize;
219
220	// The "2" more bytes requested are a safety net to insure the
221	// loops in the update routines will terminate.
222	// See "How can we deal with array overrun conditions ?" hereunder for further details.
223	mainBuffer.dirtyPages = (char *) malloc(mainBuffer.pageCount + 2);
224	if (mainBuffer.dirtyPages == NULL)
225	return false;
226
227	PFLAG_CLEAR_ALL;
228	PFLAG_CLEAR(mainBuffer.pageCount);
229	PFLAG_SET(mainBuffer.pageCount+1);
230
231	// Allocate and fill in pageInfo with start and end (inclusive) row in number of bytes
232	mainBuffer.pageInfo = (ScreenPageInfo ) malloc(mainBuffer.pageCount sizeof(ScreenPageInfo));
233	if (mainBuffer.pageInfo == NULL)
234	return false;
235
236	uint32 a = 0;
237	for (unsigned i = 0; i < mainBuffer.pageCount; i++) {
238	unsigned y1 = a / VIDEO_MODE_ROW_BYTES;
239	if (y1 >= VIDEO_MODE_Y)
240	y1 = VIDEO_MODE_Y - 1;
241
242	unsigned y2 = (a + mainBuffer.pageSize) / VIDEO_MODE_ROW_BYTES;
243	if (y2 >= VIDEO_MODE_Y)
244	y2 = VIDEO_MODE_Y - 1;
245
246	mainBuffer.pageInfo[i].top = y1;
247	mainBuffer.pageInfo[i].bottom = y2;
248
249	a += mainBuffer.pageSize;
250	if (a > mainBuffer.memLength)
251	a = mainBuffer.memLength;
252	}
253
254	// We can now write-protect the frame buffer
255	if (vm_protect((char *)mainBuffer.memStart, mainBuffer.memLength, VM_PAGE_READ) != 0)
256	return false;
257
258	// The frame buffer is sane, i.e. there is no write to it yet
259	mainBuffer.dirty = false;
260	return true;
261	}
262
263
264	/*
265	* Deinitialize VOSF system
266	*/
267
268	static void video_vosf_exit(void)
269	{
270	if (mainBuffer.pageInfo) {
271	free(mainBuffer.pageInfo);
272	mainBuffer.pageInfo = NULL;
273	}
274	if (mainBuffer.dirtyPages) {
275	free(mainBuffer.dirtyPages);
276	mainBuffer.dirtyPages = NULL;
277	}
278	}
279
280
281	/*
282	* Screen fault handler
283	*/
284
285	bool Screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction)
286	{
287	const uintptr addr = (uintptr)fault_address;
288
289	/* Someone attempted to write to the frame buffer. Make it writeable
290	* now so that the data could actually be written to. It will be made
291	* read-only back in one of the screen update_*() functions.
292	*/
293	if (((uintptr)addr - mainBuffer.memStart) < mainBuffer.memLength) {
294	const int page = ((uintptr)addr - mainBuffer.memStart) >> mainBuffer.pageBits;
295	LOCK_VOSF;
296	PFLAG_SET(page);
297	vm_protect((char *)(addr & -mainBuffer.pageSize), mainBuffer.pageSize, VM_PAGE_READ \| VM_PAGE_WRITE);
298	mainBuffer.dirty = true;
299	UNLOCK_VOSF;
300	return true;
301	}
302
303	/* Otherwise, we don't know how to handle the fault, let it crash */
304	return false;
305	}
306
307
308	/*
309	* Update display for Windowed mode and VOSF
310	*/
311
312	// From video_blit.cpp
313	extern void (Screen_blit)(uint8 dest, const uint8 * source, uint32 length);
314	extern bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order, int mac_depth);
315	extern uint32 ExpandMap[256];
316
317	/* How can we deal with array overrun conditions ?
318
319	The state of the framebuffer pages that have been touched are maintained
320	in the dirtyPages[] table. That table is (pageCount + 2) bytes long.
321
322	Terminology
323
324	"Last Page" denotes the pageCount-nth page, i.e. dirtyPages[pageCount - 1].
325	"CLEAR Page Guard" refers to the page following the Last Page but is always
326	in the CLEAR state. "SET Page Guard" refers to the page following the CLEAR
327	Page Guard but is always in the SET state.
328
329	Rough process
330
331	The update routines must determine which pages have to be blitted to the
332	screen. This job consists in finding the first_page that was touched.
333	i.e. find the next page that is SET. Then, finding how many pages were
334	touched starting from first_page. i.e. find the next page that is CLEAR.
335
336	There are two cases to check:
337
338	- Last Page is CLEAR: find_next_page_set() will reach the SET Page Guard
339	but it is beyond the valid pageCount value. Therefore, we exit from the
340	update routine.
341
342	- Last Page is SET: first_page equals (pageCount - 1) and
343	find_next_page_clear() will reach the CLEAR Page Guard. We blit the last
344	page to the screen. On the next iteration, page equals pageCount and
345	find_next_page_set() will reach the SET Page Guard. We still safely exit
346	from the update routine because the SET Page Guard position is greater
347	than pageCount.
348	*/
349
350	static inline void update_display_window_vosf(VIDEO_DRV_INIT)
351	{
352	VIDEO_MODE_INIT;
353
354	int page = 0;
355	for (;;) {
356	const unsigned first_page = find_next_page_set(page);
357	if (first_page >= mainBuffer.pageCount)
358	break;
359
360	page = find_next_page_clear(first_page);
361	PFLAG_CLEAR_RANGE(first_page, page);
362
363	// Make the dirty pages read-only again
364	const int32 offset = first_page << mainBuffer.pageBits;
365	const uint32 length = (page - first_page) << mainBuffer.pageBits;
366	vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_READ);
367
368	// There is at least one line to update
369	const int y1 = mainBuffer.pageInfo[first_page].top;
370	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
371	const int height = y2 - y1 + 1;
372
373	if (VIDEO_MODE_DEPTH < VIDEO_DEPTH_8BIT) {
374
375	// Update the_host_buffer and copy of the_buffer
376	const int src_bytes_per_row = VIDEO_MODE_ROW_BYTES;
377	const int dst_bytes_per_row = VIDEO_DRV_IMAGE->bytes_per_line;
378	const int pixels_per_byte = VIDEO_MODE_X / src_bytes_per_row;
379	int i1 = y1 * src_bytes_per_row, i2 = y1 * dst_bytes_per_row, j;
380	for (j = y1; j <= y2; j++) {
381	Screen_blit(the_host_buffer + i2, the_buffer + i1, VIDEO_MODE_X / pixels_per_byte);
382	i1 += src_bytes_per_row;
383	i2 += dst_bytes_per_row;
384	}
385
386	} else {
387
388	// Update the_host_buffer and copy of the_buffer
389	const int src_bytes_per_row = VIDEO_MODE_ROW_BYTES;
390	const int dst_bytes_per_row = VIDEO_DRV_IMAGE->bytes_per_line;
391	const int bytes_per_pixel = src_bytes_per_row / VIDEO_MODE_X;
392	int i1 = y1 * src_bytes_per_row, i2 = y1 * dst_bytes_per_row, j;
393	for (j = y1; j <= y2; j++) {
394	Screen_blit(the_host_buffer + i2, the_buffer + i1, bytes_per_pixel * VIDEO_MODE_X);
395	i1 += src_bytes_per_row;
396	i2 += dst_bytes_per_row;
397	}
398	}
399
400	if (VIDEO_DRV_HAVE_SHM)
401	XShmPutImage(x_display, VIDEO_DRV_WINDOW, VIDEO_DRV_GC, VIDEO_DRV_IMAGE, 0, y1, 0, y1, VIDEO_MODE_X, height, 0);
402	else
403	XPutImage(x_display, VIDEO_DRV_WINDOW, VIDEO_DRV_GC, VIDEO_DRV_IMAGE, 0, y1, 0, y1, VIDEO_MODE_X, height);
404	}
405	mainBuffer.dirty = false;
406	}
407
408
409	/*
410	* Update display for DGA mode and VOSF
411	* (only in Real or Direct Addressing mode)
412	*/
413
414	#if REAL_ADDRESSING \|\| DIRECT_ADDRESSING
415	static inline void update_display_dga_vosf(void)
416	{
417	VIDEO_MODE_INIT;
418
419	int page = 0;
420	for (;;) {
421	const unsigned first_page = find_next_page_set(page);
422	if (first_page >= mainBuffer.pageCount)
423	break;
424
425	page = find_next_page_clear(first_page);
426	PFLAG_CLEAR_RANGE(first_page, page);
427
428	// Make the dirty pages read-only again
429	const int32 offset = first_page << mainBuffer.pageBits;
430	const uint32 length = (page - first_page) << mainBuffer.pageBits;
431	vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_READ);
432
433	// I am sure that y2 >= y1 and depth != 1
434	const int y1 = mainBuffer.pageInfo[first_page].top;
435	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
436
437	const int bytes_per_row = VIDEO_MODE_ROW_BYTES;
438	const int bytes_per_pixel = VIDEO_MODE_ROW_BYTES / VIDEO_MODE_X;
439	int i, j;
440
441	// Check for first column from left and first column
442	// from right that have changed
443	int x1 = VIDEO_MODE_X * bytes_per_pixel - 1;
444	for (j = y1; j <= y2; j++) {
445	uint8 * const p1 = &the_buffer[j * bytes_per_row];
446	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
447	for (i = 0; i < x1; i++) {
448	if (p1[i] != p2[i]) {
449	x1 = i;
450	break;
451	}
452	}
453	}
454	x1 /= bytes_per_pixel;
455
456	int x2 = x1 * bytes_per_pixel;
457	for (j = y2; j >= y1; j--) {
458	uint8 * const p1 = &the_buffer[j * bytes_per_row];
459	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
460	for (i = VIDEO_MODE_X * bytes_per_pixel - 1; i > x2; i--) {
461	if (p1[i] != p2[i]) {
462	x2 = i;
463	break;
464	}
465	}
466	}
467	x2 /= bytes_per_pixel;
468
469	// Update the_host_buffer and copy of the_buffer
470	// There should be at least one pixel to copy
471	const int width = x2 - x1 + 1;
472	i = y1 * bytes_per_row + x1 * bytes_per_pixel;
473	for (j = y1; j <= y2; j++) {
474	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
475	memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
476	i += bytes_per_row;
477	}
478	}
479	mainBuffer.dirty = false;
480	}
481	#endif
482
483	#endif /* ENABLE_VOSF */
484
485	#endif /* VIDEO_VOSF_H */