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
}

static int zero_fd = -1;

#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;
}


/*
 *  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;
                // Align the frame buffer on 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 == 0) || (mainBuffer.pageInfo == 0))
                        return false;
                
                mainBuffer.dirty = false;

                PFLAG_CLEAR_ALL;
                // Safety net to insure the loops in the update routines will terminate
                // See a discussion in <video_vosf.h> 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;
}


/*
 *  Page-aligned memory allocation
 */

// 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;
}

// Screen fault handler
static bool screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction)
{
        D(bug("screen_fault_handler: ADDR=0x%08X from IP=0x%08X\n", fault_address, fault_instruction));
        const uintptr addr = (uintptr)fault_address;
        
        /* Someone attempted to write to the frame buffer. Make it writeable
         * now so that the data could actually be written. It will be made
         * read-only back in one of the screen update_*() functions.
         */
        if ((addr >= mainBuffer.memStart) && (addr < mainBuffer.memEnd)) {
                const int page  = (addr - mainBuffer.memStart) >> mainBuffer.pageBits;
                caddr_t page_ad = (caddr_t)(addr & -mainBuffer.pageSize);
                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);

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

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

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

There are two cases to check:

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

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

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

                // Make the dirty pages read-only again
                const int32 offset  = first_page << mainBuffer.pageBits;
                const uint32 length = (page - first_page) << mainBuffer.pageBits;
                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 (have_shm)
                        XShmPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.mode.x, height, 0);
                else
                        XPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.mode.x, height);
        }

        mainBuffer.dirty = false;
}


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

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

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

                // Make the dirty pages read-only again
                const int32 offset  = first_page << mainBuffer.pageBits;
                const uint32 length = (page - first_page) << mainBuffer.pageBits;
                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:	1.19
Committed:	2001-06-28T21:20:00Z (23 years, 5 months ago) by cebix
Content type:	text/plain
Branch:	MAIN
Changes since 1.18:	+212 -1 lines
Log Message:	video_x.cpp supports resolution switching in windowed mode: the available resolutions are 512x384, 640x480, 800x600, 1024x768 and 1280x1024 (the prefs editor has to be updated to reflect this). The resolution selected in the prefs editor is used as the default, but it can be changed in the Monitors control panel. So far only tested with direct addressing.
#	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	static int zero_fd = -1;
135
136	#ifdef HAVE_PTHREADS
137	static pthread_mutex_t vosf_lock = PTHREAD_MUTEX_INITIALIZER; // Mutex to protect frame buffer (dirtyPages in fact)
138	#define LOCK_VOSF pthread_mutex_lock(&vosf_lock);
139	#define UNLOCK_VOSF pthread_mutex_unlock(&vosf_lock);
140	#else
141	#define LOCK_VOSF
142	#define UNLOCK_VOSF
143	#endif
144
145	static int log_base_2(uint32 x)
146	{
147	uint32 mask = 0x80000000;
148	int l = 31;
149	while (l >= 0 && (x & mask) == 0) {
150	mask >>= 1;
151	l--;
152	}
153	return l;
154	}
155
156
157	/*
158	* Initialize mainBuffer structure
159	*/
160
161	static bool video_init_buffer(void)
162	{
163	if (use_vosf) {
164	const uint32 page_size = getpagesize();
165	const uint32 page_mask = page_size - 1;
166
167	mainBuffer.memBase = (uintptr) the_buffer;
168	// Align the frame buffer on page boundary
169	mainBuffer.memStart = (uintptr)((((unsigned long) the_buffer) + page_mask) & ~page_mask);
170	mainBuffer.memLength = the_buffer_size;
171	mainBuffer.memEnd = mainBuffer.memStart + mainBuffer.memLength;
172
173	mainBuffer.pageSize = page_size;
174	mainBuffer.pageCount = (mainBuffer.memLength + page_mask)/mainBuffer.pageSize;
175	mainBuffer.pageBits = log_base_2(mainBuffer.pageSize);
176
177	if (mainBuffer.dirtyPages) {
178	free(mainBuffer.dirtyPages);
179	mainBuffer.dirtyPages = NULL;
180	}
181
182	mainBuffer.dirtyPages = (char *) malloc(mainBuffer.pageCount + 2);
183
184	if (mainBuffer.pageInfo) {
185	free(mainBuffer.pageInfo);
186	mainBuffer.pageInfo = NULL;
187	}
188
189	mainBuffer.pageInfo = (ScreenPageInfo ) malloc(mainBuffer.pageCount sizeof(ScreenPageInfo));
190
191	if ((mainBuffer.dirtyPages == 0) \|\| (mainBuffer.pageInfo == 0))
192	return false;
193
194	mainBuffer.dirty = false;
195
196	PFLAG_CLEAR_ALL;
197	// Safety net to insure the loops in the update routines will terminate
198	// See a discussion in <video_vosf.h> for further details
199	PFLAG_CLEAR(mainBuffer.pageCount);
200	PFLAG_SET(mainBuffer.pageCount+1);
201
202	uint32 a = 0;
203	for (int i = 0; i < mainBuffer.pageCount; i++) {
204	int y1 = a / VideoMonitor.mode.bytes_per_row;
205	if (y1 >= VideoMonitor.mode.y)
206	y1 = VideoMonitor.mode.y - 1;
207
208	int y2 = (a + mainBuffer.pageSize) / VideoMonitor.mode.bytes_per_row;
209	if (y2 >= VideoMonitor.mode.y)
210	y2 = VideoMonitor.mode.y - 1;
211
212	mainBuffer.pageInfo[i].top = y1;
213	mainBuffer.pageInfo[i].bottom = y2;
214
215	a += mainBuffer.pageSize;
216	if (a > mainBuffer.memLength)
217	a = mainBuffer.memLength;
218	}
219
220	// We can now write-protect the frame buffer
221	if (vm_protect((char *)mainBuffer.memStart, mainBuffer.memLength, VM_PAGE_READ) != 0)
222	return false;
223	}
224	return true;
225	}
226
227
228	/*
229	* Page-aligned memory allocation
230	*/
231
232	// Extend size to page boundary
233	static uint32 page_extend(uint32 size)
234	{
235	const uint32 page_size = getpagesize();
236	const uint32 page_mask = page_size - 1;
237	return (size + page_mask) & ~page_mask;
238	}
239
240	// Screen fault handler
241	static bool screen_fault_handler(sigsegv_address_t fault_address, sigsegv_address_t fault_instruction)
242	{
243	D(bug("screen_fault_handler: ADDR=0x%08X from IP=0x%08X\n", fault_address, fault_instruction));
244	const uintptr addr = (uintptr)fault_address;
245
246	/* Someone attempted to write to the frame buffer. Make it writeable
247	* now so that the data could actually be written. It will be made
248	* read-only back in one of the screen update_*() functions.
249	*/
250	if ((addr >= mainBuffer.memStart) && (addr < mainBuffer.memEnd)) {
251	const int page = (addr - mainBuffer.memStart) >> mainBuffer.pageBits;
252	caddr_t page_ad = (caddr_t)(addr & -mainBuffer.pageSize);
253	LOCK_VOSF;
254	PFLAG_SET(page);
255	vm_protect((char *)page_ad, mainBuffer.pageSize, VM_PAGE_READ \| VM_PAGE_WRITE);
256	mainBuffer.dirty = true;
257	UNLOCK_VOSF;
258	return true;
259	}
260
261	/* Otherwise, we don't know how to handle the fault, let it crash */
262	fprintf(stderr, "do_handle_screen_fault: unhandled address 0x%08X", addr);
263	if (fault_instruction != SIGSEGV_INVALID_PC)
264	fprintf(stderr, " [IP=0x%08X]", fault_instruction);
265	fprintf(stderr, "\n");
266	#if EMULATED_68K
267	uaecptr nextpc;
268	extern void m68k_dumpstate(uaecptr *nextpc);
269	m68k_dumpstate(&nextpc);
270	#endif
271	#ifdef ENABLE_MON
272	char *arg[4] = {"mon", "-m", "-r", NULL};
273	mon(3, arg);
274	QuitEmulator();
275	#endif
276	return false;
277	}
278
279	/*
280	* Update display for Windowed mode and VOSF
281	*/
282
283	// From video_blit.cpp
284	extern void (Screen_blit)(uint8 dest, const uint8 * source, uint32 length);
285	extern bool Screen_blitter_init(XVisualInfo * visual_info, bool native_byte_order);
286
287	/* How can we deal with array overrun conditions ?
288
289	The state of the framebuffer pages that have been touched are maintained
290	in the dirtyPages[] table. That table is (pageCount + 2) bytes long.
291
292	Terminology
293
294	"Last Page" denotes the pageCount-nth page, i.e. dirtyPages[pageCount - 1].
295	"CLEAR Page Guard" refers to the page following the Last Page but is always
296	in the CLEAR state. "SET Page Guard" refers to the page following the CLEAR
297	Page Guard but is always in the SET state.
298
299	Rough process
300
301	The update routines must determine which pages have to be blitted to the
302	screen. This job consists in finding the first_page that was touched.
303	i.e. find the next page that is SET. Then, finding how many pages were
304	touched starting from first_page. i.e. find the next page that is CLEAR.
305
306	There are two cases to check:
307
308	- Last Page is CLEAR: find_next_page_set() will reach the SET Page Guard
309	but it is beyond the valid pageCount value. Therefore, we exit from the
310	update routine.
311
312	- Last Page is SET: first_page equals (pageCount - 1) and
313	find_next_page_clear() will reach the CLEAR Page Guard. We blit the last
314	page to the screen. On the next iteration, page equals pageCount and
315	find_next_page_set() will reach the SET Page Guard. We still safely exit
316	from the update routine because the SET Page Guard position is greater
317	than pageCount.
318	*/
319
320	static inline void update_display_window_vosf(void)
321	{
322	int page = 0;
323	for (;;) {
324	const int first_page = find_next_page_set(page);
325	if (first_page >= mainBuffer.pageCount)
326	break;
327
328	page = find_next_page_clear(first_page);
329	PFLAG_CLEAR_RANGE(first_page, page);
330
331	// Make the dirty pages read-only again
332	const int32 offset = first_page << mainBuffer.pageBits;
333	const uint32 length = (page - first_page) << mainBuffer.pageBits;
334	vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_READ);
335
336	// There is at least one line to update
337	const int y1 = mainBuffer.pageInfo[first_page].top;
338	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
339	const int height = y2 - y1 + 1;
340
341	const int bytes_per_row = VideoMonitor.mode.bytes_per_row;
342	const int bytes_per_pixel = VideoMonitor.mode.bytes_per_row / VideoMonitor.mode.x;
343	int i = y1 * bytes_per_row, j;
344
345	if (VideoMonitor.mode.depth == VDEPTH_1BIT) {
346
347	// Update the_host_buffer and copy of the_buffer
348	for (j = y1; j <= y2; j++) {
349	Screen_blit(the_host_buffer + i, the_buffer + i, VideoMonitor.mode.x >> 3);
350	i += bytes_per_row;
351	}
352
353	} else {
354
355	// Update the_host_buffer and copy of the_buffer
356	for (j = y1; j <= y2; j++) {
357	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * VideoMonitor.mode.x);
358	i += bytes_per_row;
359	}
360	}
361
362	if (have_shm)
363	XShmPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.mode.x, height, 0);
364	else
365	XPutImage(x_display, the_win, the_gc, img, 0, y1, 0, y1, VideoMonitor.mode.x, height);
366	}
367
368	mainBuffer.dirty = false;
369	}
370
371
372	/*
373	* Update display for DGA mode and VOSF
374	* (only in Direct Addressing mode)
375	*/
376
377	#if REAL_ADDRESSING \|\| DIRECT_ADDRESSING
378	static inline void update_display_dga_vosf(void)
379	{
380	int page = 0;
381	for (;;) {
382	const int first_page = find_next_page_set(page);
383	if (first_page >= mainBuffer.pageCount)
384	break;
385
386	page = find_next_page_clear(first_page);
387	PFLAG_CLEAR_RANGE(first_page, page);
388
389	// Make the dirty pages read-only again
390	const int32 offset = first_page << mainBuffer.pageBits;
391	const uint32 length = (page - first_page) << mainBuffer.pageBits;
392	vm_protect((char *)mainBuffer.memStart + offset, length, VM_PAGE_READ);
393
394	// I am sure that y2 >= y1 and depth != 1
395	const int y1 = mainBuffer.pageInfo[first_page].top;
396	const int y2 = mainBuffer.pageInfo[page - 1].bottom;
397
398	const int bytes_per_row = VideoMonitor.mode.bytes_per_row;
399	const int bytes_per_pixel = VideoMonitor.mode.bytes_per_row / VideoMonitor.mode.x;
400	int i, j;
401
402	// Check for first column from left and first column
403	// from right that have changed
404	int x1 = VideoMonitor.mode.x * bytes_per_pixel - 1;
405	for (j = y1; j <= y2; j++) {
406	uint8 * const p1 = &the_buffer[j * bytes_per_row];
407	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
408	for (i = 0; i < x1; i++) {
409	if (p1[i] != p2[i]) {
410	x1 = i;
411	break;
412	}
413	}
414	}
415	x1 /= bytes_per_pixel;
416
417	int x2 = x1 * bytes_per_pixel;
418	for (j = y2; j >= y1; j--) {
419	uint8 * const p1 = &the_buffer[j * bytes_per_row];
420	uint8 * const p2 = &the_buffer_copy[j * bytes_per_row];
421	for (i = VideoMonitor.mode.x * bytes_per_pixel - 1; i > x2; i--) {
422	if (p1[i] != p2[i]) {
423	x2 = i;
424	break;
425	}
426	}
427	}
428	x2 /= bytes_per_pixel;
429
430	// Update the_host_buffer and copy of the_buffer
431	// There should be at least one pixel to copy
432	const int width = x2 - x1 + 1;
433	i = y1 * bytes_per_row + x1 * bytes_per_pixel;
434	for (j = y1; j <= y2; j++) {
435	Screen_blit(the_host_buffer + i, the_buffer + i, bytes_per_pixel * width);
436	memcpy(the_buffer_copy + i, the_buffer + i, bytes_per_pixel * width);
437	i += bytes_per_row;
438	}
439	}
440	mainBuffer.dirty = false;
441	}
442	#endif
443
444	#endif /* ENABLE_VOSF */
445
446	#endif /* VIDEO_VOSF_H */