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 is #include'd in video_x.cpp
#ifdef ENABLE_VOSF

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

// 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 screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction);

static bool video_vosf_init(X11_monitor_desc &monitor)
{
        const video_mode &mode = monitor.get_current_mode();

        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 / mode.bytes_per_row;
                if (y1 >= mode.y)
                        y1 = mode.y - 1;

                unsigned y2 = (a + mainBuffer.pageSize) / mode.bytes_per_row;
                if (y2 >= mode.y)
                        y2 = 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;
        
        // Initialize the handler for SIGSEGV
        if (!sigsegv_install_handler(screen_fault_handler))
                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
 */

static bool screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction)
{
//      D(bug("screen_fault_handler: ADDR=%p from IP=%p\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 (((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, video_depth 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(driver_window *drv)
{
        const video_mode &mode = drv->monitor.get_current_mode();

        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 (mode.depth < VDEPTH_8BIT) {

                        // Update the_host_buffer and copy of the_buffer
                        const int src_bytes_per_row = mode.bytes_per_row;
                        const int dst_bytes_per_row = drv->img->bytes_per_line;
                        const int pixels_per_byte = 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, 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 = mode.bytes_per_row;
                        const int dst_bytes_per_row = drv->img->bytes_per_line;
                        const int bytes_per_pixel = src_bytes_per_row / 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 * mode.x);
                                i1 += src_bytes_per_row;
                                i2 += dst_bytes_per_row;
                        }
                }

                if (drv->have_shm)
                        XShmPutImage(x_display, drv->w, drv->gc, drv->img, 0, y1, 0, y1, mode.x, height, 0);
                else
                        XPutImage(x_display, drv->w, drv->gc, drv->img, 0, y1, 0, y1, 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)
{
        const video_mode &mode = drv->monitor.get_current_mode();

        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 = mode.bytes_per_row;
                const int bytes_per_pixel = mode.bytes_per_row / mode.x;
                int i, j;
                
                // Check for first column from left and first column
                // from right that have changed
                int x1 = 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 = 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:	1.32
Committed:	2002-05-16T15:48:06Z (22 years, 1 month ago) by gbeauche
Content type:	text/plain
Branch:	MAIN
CVS Tags:	nigel-build-12, nigel-build-13
Changes since 1.31:	+0 -19 lines
Log Message:	- video_vosh.h (Screen_fault_handler): Move unrecoverable fault case to... - main_unix.cpp (sigsegv_dump_state): ... Here. - sigsegv.h (sigsegv_fault_handler_t): Rename from sigsegv_handler_t. - sigsegv.h (sigsegv_state_dumper_t): New.
#	User	Rev	Content
1	gbeauche	1.1	/*
2			* video_vosf.h - Video/graphics emulation, video on SEGV signals support
3			*
4	cebix	1.30	* Basilisk II (C) 1997-2002 Christian Bauer
5	gbeauche	1.1	*
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	cebix	1.19	#include <fcntl.h>
28			#include <sys/mman.h>
29			#include "sigsegv.h"
30			#include "vm_alloc.h"
31
32			// Variables for Video on SEGV support
33	gbeauche	1.20	static uint8 *the_host_buffer; // Host frame buffer in VOSF mode
34	cebix	1.19
35			struct ScreenPageInfo {
36			int top, bottom; // Mapping between this virtual page and Mac scanlines
37			};
38
39			struct ScreenInfo {
40			uintptr memStart; // Start address aligned to page boundary
41			uint32 memLength; // Length of the memory addressed by the screen pages
42
43	gbeauche	1.27	uintptr pageSize; // Size of a page
44	cebix	1.19	int pageBits; // Shift count to get the page number
45			uint32 pageCount; // Number of pages allocated to the screen
46
47			bool dirty; // Flag: set if the frame buffer was touched
48			char * dirtyPages; // Table of flags set if page was altered
49			ScreenPageInfo * pageInfo; // Table of mappings page -> Mac scanlines
50			};
51
52			static ScreenInfo mainBuffer;
53
54			#define PFLAG_SET_VALUE 0x00
55			#define PFLAG_CLEAR_VALUE 0x01
56			#define PFLAG_SET_VALUE_4 0x00000000
57			#define PFLAG_CLEAR_VALUE_4 0x01010101
58			#define PFLAG_SET(page) mainBuffer.dirtyPages[page] = PFLAG_SET_VALUE
59			#define PFLAG_CLEAR(page) mainBuffer.dirtyPages[page] = PFLAG_CLEAR_VALUE
60			#define PFLAG_ISSET(page) (mainBuffer.dirtyPages[page] == PFLAG_SET_VALUE)
61			#define PFLAG_ISCLEAR(page) (mainBuffer.dirtyPages[page] != PFLAG_SET_VALUE)
62
63			#ifdef UNALIGNED_PROFITABLE
64			# define PFLAG_ISSET_4(page) (((uint32 )(mainBuffer.dirtyPages + (page))) == PFLAG_SET_VALUE_4)
65			# define PFLAG_ISCLEAR_4(page) (((uint32 )(mainBuffer.dirtyPages + (page))) == PFLAG_CLEAR_VALUE_4)
66			#else
67			# define PFLAG_ISSET_4(page) \
68			PFLAG_ISSET(page ) && PFLAG_ISSET(page+1) \
69			&& PFLAG_ISSET(page+2) && PFLAG_ISSET(page+3)
70			# define PFLAG_ISCLEAR_4(page) \
71			PFLAG_ISCLEAR(page ) && PFLAG_ISCLEAR(page+1) \
72			&& PFLAG_ISCLEAR(page+2) && PFLAG_ISCLEAR(page+3)
73			#endif
74
75			// Set the selected page range [ first_page, last_page [ into the SET state
76			#define PFLAG_SET_RANGE(first_page, last_page) \
77			memset(mainBuffer.dirtyPages + (first_page), PFLAG_SET_VALUE, \
78			(last_page) - (first_page))
79
80			// Set the selected page range [ first_page, last_page [ into the CLEAR state
81			#define PFLAG_CLEAR_RANGE(first_page, last_page) \
82			memset(mainBuffer.dirtyPages + (first_page), PFLAG_CLEAR_VALUE, \
83			(last_page) - (first_page))
84
85			#define PFLAG_SET_ALL do { \
86			PFLAG_SET_RANGE(0, mainBuffer.pageCount); \
87			mainBuffer.dirty = true; \
88			} while (0)
89
90			#define PFLAG_CLEAR_ALL do { \
91			PFLAG_CLEAR_RANGE(0, mainBuffer.pageCount); \
92			mainBuffer.dirty = false; \
93			} while (0)
94
95			// Set the following macro definition to 1 if your system
96			// provides a really fast strchr() implementation
97			//#define HAVE_FAST_STRCHR 0
98
99			static inline int find_next_page_set(int page)
100			{
101			#if HAVE_FAST_STRCHR
102			char *match = strchr(mainBuffer.dirtyPages + page, PFLAG_SET_VALUE);
103			return match ? match - mainBuffer.dirtyPages : mainBuffer.pageCount;
104			#else
105			while (PFLAG_ISCLEAR_4(page))
106			page += 4;
107			while (PFLAG_ISCLEAR(page))
108			page++;
109			return page;
110			#endif
111			}
112
113			static inline int find_next_page_clear(int page)
114			{
115			#if HAVE_FAST_STRCHR
116			char *match = strchr(mainBuffer.dirtyPages + page, PFLAG_CLEAR_VALUE);
117			return match ? match - mainBuffer.dirtyPages : mainBuffer.pageCount;
118			#else
119			while (PFLAG_ISSET_4(page))
120			page += 4;
121			while (PFLAG_ISSET(page))
122			page++;
123			return page;
124			#endif
125			}
126
127			#ifdef HAVE_PTHREADS
128			static pthread_mutex_t vosf_lock = PTHREAD_MUTEX_INITIALIZER; // Mutex to protect frame buffer (dirtyPages in fact)
129			#define LOCK_VOSF pthread_mutex_lock(&vosf_lock);
130			#define UNLOCK_VOSF pthread_mutex_unlock(&vosf_lock);
131			#else
132			#define LOCK_VOSF
133			#define UNLOCK_VOSF
134			#endif
135
136			static int log_base_2(uint32 x)
137			{
138			uint32 mask = 0x80000000;
139			int l = 31;
140			while (l >= 0 && (x & mask) == 0) {
141			mask >>= 1;
142			l--;
143			}
144			return l;
145			}
146
147	gbeauche	1.20	// Extend size to page boundary
148			static uint32 page_extend(uint32 size)
149			{
150			const uint32 page_size = getpagesize();
151			const uint32 page_mask = page_size - 1;
152			return (size + page_mask) & ~page_mask;
153			}
154
155	cebix	1.19
156			/*
157	gbeauche	1.27	* Initialize the VOSF system (mainBuffer structure, SIGSEGV handler)
158	cebix	1.19	*/
159
160	gbeauche	1.27	static bool screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction);
161
162	cebix	1.31	static bool video_vosf_init(X11_monitor_desc &monitor)
163	cebix	1.19	{
164	cebix	1.31	const video_mode &mode = monitor.get_current_mode();
165
166	gbeauche	1.27	const uintptr page_size = getpagesize();
167			const uintptr page_mask = page_size - 1;
168
169			// Round up frame buffer base to page boundary
170			mainBuffer.memStart = (((uintptr) the_buffer) + page_mask) & ~page_mask;
171
172			// The frame buffer size shall already be aligned to page boundary (use page_extend)
173			mainBuffer.memLength = the_buffer_size;
174
175			mainBuffer.pageSize = page_size;
176			mainBuffer.pageBits = log_base_2(mainBuffer.pageSize);
177			mainBuffer.pageCount = (mainBuffer.memLength + page_mask)/mainBuffer.pageSize;
178
179			// The "2" more bytes requested are a safety net to insure the
180			// loops in the update routines will terminate.
181			// See "How can we deal with array overrun conditions ?" hereunder for further details.
182	gbeauche	1.29	mainBuffer.dirtyPages = (char *) malloc(mainBuffer.pageCount + 2);
183			if (mainBuffer.dirtyPages == NULL)
184	gbeauche	1.27	return false;
185	cebix	1.19
186	gbeauche	1.27	PFLAG_CLEAR_ALL;
187			PFLAG_CLEAR(mainBuffer.pageCount);
188			PFLAG_SET(mainBuffer.pageCount+1);
189
190			// Allocate and fill in pageInfo with start and end (inclusive) row in number of bytes
191	gbeauche	1.29	mainBuffer.pageInfo = (ScreenPageInfo ) malloc(mainBuffer.pageCount sizeof(ScreenPageInfo));
192			if (mainBuffer.pageInfo == NULL)
193	gbeauche	1.27	return false;
194
195			uint32 a = 0;
196	cebix	1.28	for (unsigned i = 0; i < mainBuffer.pageCount; i++) {
197	cebix	1.31	unsigned y1 = a / mode.bytes_per_row;
198			if (y1 >= mode.y)
199			y1 = mode.y - 1;
200
201			unsigned y2 = (a + mainBuffer.pageSize) / mode.bytes_per_row;
202			if (y2 >= mode.y)
203			y2 = mode.y - 1;
204	gbeauche	1.27
205			mainBuffer.pageInfo[i].top = y1;
206			mainBuffer.pageInfo[i].bottom = y2;
207
208			a += mainBuffer.pageSize;
209			if (a > mainBuffer.memLength)
210			a = mainBuffer.memLength;
211			}
212
213			// We can now write-protect the frame buffer
214			if (vm_protect((char *)mainBuffer.memStart, mainBuffer.memLength, VM_PAGE_READ) != 0)
215			return false;
216
217			// Initialize the handler for SIGSEGV
218			if (!sigsegv_install_handler(screen_fault_handler))
219			return false;
220
221			// The frame buffer is sane, i.e. there is no write to it yet
222			mainBuffer.dirty = false;
223			return true;
224			}
225	cebix	1.19
226
227	gbeauche	1.27	/*
228			* Deinitialize VOSF system
229			*/
230	cebix	1.19
231	gbeauche	1.27	static void video_vosf_exit(void)
232			{
233	gbeauche	1.29	if (mainBuffer.pageInfo) {
234			free(mainBuffer.pageInfo);
235			mainBuffer.pageInfo = NULL;
236	gbeauche	1.27	}
237	gbeauche	1.29	if (mainBuffer.dirtyPages) {
238			free(mainBuffer.dirtyPages);
239			mainBuffer.dirtyPages = NULL;
240	cebix	1.19	}
241			}
242
243
244	gbeauche	1.1	/*
245	gbeauche	1.20	* Screen fault handler
246	gbeauche	1.1	*/
247
248	gbeauche	1.16	static bool screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction)
249	gbeauche	1.1	{
250	gbeauche	1.27	// D(bug("screen_fault_handler: ADDR=%p from IP=%p\n", fault_address, fault_instruction));
251	gbeauche	1.16	const uintptr addr = (uintptr)fault_address;
252
253	gbeauche	1.11	/* Someone attempted to write to the frame buffer. Make it writeable
254	gbeauche	1.20	* now so that the data could actually be written to. It will be made
255	gbeauche	1.11	* read-only back in one of the screen update_*() functions.
256			*/
257	gbeauche	1.27	if (((uintptr)addr - mainBuffer.memStart) < mainBuffer.memLength) {
258			const int page = ((uintptr)addr - mainBuffer.memStart) >> mainBuffer.pageBits;
259	gbeauche	1.11	LOCK_VOSF;
260			PFLAG_SET(page);
261	gbeauche	1.27	vm_protect((char *)(addr & -mainBuffer.pageSize), mainBuffer.pageSize, VM_PAGE_READ \| VM_PAGE_WRITE);
262	gbeauche	1.13	mainBuffer.dirty = true;
263	gbeauche	1.11	UNLOCK_VOSF;
264	gbeauche	1.16	return true;
265	gbeauche	1.1	}
266
267	gbeauche	1.11	/* Otherwise, we don't know how to handle the fault, let it crash */
268	gbeauche	1.16	return false;
269	gbeauche	1.1	}
270
271	gbeauche	1.20
272	gbeauche	1.1	/*
273			* Update display for Windowed mode and VOSF
274			*/
275
276	gbeauche	1.13	// From video_blit.cpp
277			extern void (Screen_blit)(uint8 dest, const uint8 * source, uint32 length);
278	cebix	1.22	extern bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order, video_depth mac_depth);
279	cebix	1.23	extern uint32 ExpandMap[256];
280	gbeauche	1.13
281	gbeauche	1.12	/* How can we deal with array overrun conditions ?
282
283			The state of the framebuffer pages that have been touched are maintained
284			in the dirtyPages[] table. That table is (pageCount + 2) bytes long.
285
286			Terminology
287
288			"Last Page" denotes the pageCount-nth page, i.e. dirtyPages[pageCount - 1].
289			"CLEAR Page Guard" refers to the page following the Last Page but is always
290			in the CLEAR state. "SET Page Guard" refers to the page following the CLEAR
291			Page Guard but is always in the SET state.
292
293			Rough process
294
295	gbeauche	1.13	The update routines must determine which pages have to be blitted to the
296	gbeauche	1.12	screen. This job consists in finding the first_page that was touched.
297			i.e. find the next page that is SET. Then, finding how many pages were
298			touched starting from first_page. i.e. find the next page that is CLEAR.
299
300	gbeauche	1.13	There are two cases to check:
301	gbeauche	1.12
302			- Last Page is CLEAR: find_next_page_set() will reach the SET Page Guard
303			but it is beyond the valid pageCount value. Therefore, we exit from the
304			update routine.
305
306			- Last Page is SET: first_page equals (pageCount - 1) and
307			find_next_page_clear() will reach the CLEAR Page Guard. We blit the last
308			page to the screen. On the next iteration, page equals pageCount and
309			find_next_page_set() will reach the SET Page Guard. We still safely exit
310			from the update routine because the SET Page Guard position is greater
311			than pageCount.
312			*/
313
314	cebix	1.21	static inline void update_display_window_vosf(driver_window *drv)
315	gbeauche	1.1	{
316	cebix	1.31	const video_mode &mode = drv->monitor.get_current_mode();
317
318	gbeauche	1.1	int page = 0;
319			for (;;) {
320	cebix	1.28	const unsigned first_page = find_next_page_set(page);
321	gbeauche	1.11	if (first_page >= mainBuffer.pageCount)
322	gbeauche	1.1	break;
323	gbeauche	1.11
324			page = find_next_page_clear(first_page);
325			PFLAG_CLEAR_RANGE(first_page, page);
326	cebix	1.7
327	gbeauche	1.1	// Make the dirty pages read-only again
328			const int32 offset = first_page << mainBuffer.pageBits;
329			const uint32 length = (page - first_page) << mainBuffer.pageBits;
330	gbeauche	1.17	vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_READ);
331	gbeauche	1.1
332			// There is at least one line to update
333			const int y1 = mainBuffer.pageInfo[first_page].top;
334			const int y2 = mainBuffer.pageInfo[page - 1].bottom;
335			const int height = y2 - y1 + 1;
336
337	cebix	1.31	if (mode.depth < VDEPTH_8BIT) {
338	cebix	1.6
339			// Update the_host_buffer and copy of the_buffer
340	cebix	1.31	const int src_bytes_per_row = mode.bytes_per_row;
341	cebix	1.24	const int dst_bytes_per_row = drv->img->bytes_per_line;
342	cebix	1.31	const int pixels_per_byte = mode.x / src_bytes_per_row;
343	cebix	1.24	int i1 = y1 * src_bytes_per_row, i2 = y1 * dst_bytes_per_row, j;
344	cebix	1.6	for (j = y1; j <= y2; j++) {
345	cebix	1.31	Screen_blit(the_host_buffer + i2, the_buffer + i1, mode.x / pixels_per_byte);
346	cebix	1.24	i1 += src_bytes_per_row;
347			i2 += dst_bytes_per_row;
348	cebix	1.6	}
349
350			} else {
351
352			// Update the_host_buffer and copy of the_buffer
353	cebix	1.31	const int src_bytes_per_row = mode.bytes_per_row;
354	cebix	1.23	const int dst_bytes_per_row = drv->img->bytes_per_line;
355	cebix	1.31	const int bytes_per_pixel = src_bytes_per_row / mode.x;
356	cebix	1.23	int i1 = y1 * src_bytes_per_row, i2 = y1 * dst_bytes_per_row, j;
357	cebix	1.6	for (j = y1; j <= y2; j++) {
358	cebix	1.31	Screen_blit(the_host_buffer + i2, the_buffer + i1, bytes_per_pixel * mode.x);
359	cebix	1.23	i1 += src_bytes_per_row;
360			i2 += dst_bytes_per_row;
361	cebix	1.6	}
362	gbeauche	1.1	}
363	cebix	1.15
364	cebix	1.21	if (drv->have_shm)
365	cebix	1.31	XShmPutImage(x_display, drv->w, drv->gc, drv->img, 0, y1, 0, y1, mode.x, height, 0);
366	gbeauche	1.1	else
367	cebix	1.31	XPutImage(x_display, drv->w, drv->gc, drv->img, 0, y1, 0, y1, mode.x, height);
368	gbeauche	1.1	}
369	gbeauche	1.13	mainBuffer.dirty = false;
370	gbeauche	1.1	}
371
372
373			/*
374			* Update display for DGA mode and VOSF
375	gbeauche	1.20	* (only in Real or Direct Addressing mode)
376	gbeauche	1.1	*/
377
378			#if REAL_ADDRESSING \|\| DIRECT_ADDRESSING
379			static inline void update_display_dga_vosf(void)
380			{
381	cebix	1.31	const video_mode &mode = drv->monitor.get_current_mode();
382
383	gbeauche	1.1	int page = 0;
384			for (;;) {
385	cebix	1.28	const unsigned first_page = find_next_page_set(page);
386	gbeauche	1.11	if (first_page >= mainBuffer.pageCount)
387	gbeauche	1.1	break;
388	gbeauche	1.11
389			page = find_next_page_clear(first_page);
390			PFLAG_CLEAR_RANGE(first_page, page);
391
392	gbeauche	1.1	// Make the dirty pages read-only again
393			const int32 offset = first_page << mainBuffer.pageBits;
394			const uint32 length = (page - first_page) << mainBuffer.pageBits;
395	gbeauche	1.17	vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_READ);
396	gbeauche	1.1
397			// I am sure that y2 >= y1 and depth != 1
398			const int y1 = mainBuffer.pageInfo[first_page].top;
399			const int y2 = mainBuffer.pageInfo[page - 1].bottom;
400
401	cebix	1.31	const int bytes_per_row = mode.bytes_per_row;
402			const int bytes_per_pixel = mode.bytes_per_row / mode.x;
403	gbeauche	1.1	int i, j;
404
405			// Check for first column from left and first column
406			// from right that have changed
407	cebix	1.31	int x1 = mode.x * bytes_per_pixel - 1;
408	gbeauche	1.1	for (j = y1; j <= y2; j++) {
409			uint8 * const p1 = &the_buffer[j * bytes_per_row];
410			uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
411			for (i = 0; i < x1; i++) {
412			if (p1[i] != p2[i]) {
413			x1 = i;
414			break;
415			}
416			}
417			}
418			x1 /= bytes_per_pixel;
419
420			int x2 = x1 * bytes_per_pixel;
421			for (j = y2; j >= y1; j--) {
422			uint8 * const p1 = &the_buffer[j * bytes_per_row];
423			uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
424	cebix	1.31	for (i = mode.x * bytes_per_pixel - 1; i > x2; i--) {
425	gbeauche	1.1	if (p1[i] != p2[i]) {
426			x2 = i;
427			break;
428			}
429			}
430			}
431			x2 /= bytes_per_pixel;
432
433			// Update the_host_buffer and copy of the_buffer
434			// There should be at least one pixel to copy
435			const int width = x2 - x1 + 1;
436			i = y1 * bytes_per_row + x1 * bytes_per_pixel;
437			for (j = y1; j <= y2; j++) {
438	gbeauche	1.13	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
439	gbeauche	1.1	memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
440			i += bytes_per_row;
441			}
442			}
443	gbeauche	1.13	mainBuffer.dirty = false;
444	gbeauche	1.1	}
445			#endif
446
447			#endif /* ENABLE_VOSF */
448
449			#endif /* VIDEO_VOSF_H */