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modex.c
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/* tab:4
*
* modex.c - VGA mode X graphics routines
*
* "Copyright(c) 2004-2011 by Steven S. Lumetta."
*
* Permission to use, copy, modify, and distribute this software and its
* documentation for any purpose, without fee, and without written agreement is
* hereby granted, provided that the above copyright notice and the following
* two paragraphs appear in all copies of this software.
*
* IN NO EVENT SHALL THE AUTHOR OR THE UNIVERSITY OF ILLINOIS BE LIABLE TO
* ANY PARTY FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
* DAMAGES ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION,
* EVEN IF THE AUTHOR AND/OR THE UNIVERSITY OF ILLINOIS HAS BEEN ADVISED
* OF THE POSSIBILITY OF SUCH DAMAGE.
*
* THE AUTHOR AND THE UNIVERSITY OF ILLINOIS SPECIFICALLY DISCLAIM ANY
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE
* PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND NEITHER THE AUTHOR NOR
* THE UNIVERSITY OF ILLINOIS HAS ANY OBLIGATION TO PROVIDE MAINTENANCE,
* SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS."
*
* Author: Steve Lumetta
* Version: 5
* Creation Date: Fri Sep 10 09:59:17 2004
* Filename: modex.c
* History:
* SL 1 Fri Sep 10 09:59:17 2004
* First written.
* SL 2 Sat Sep 12 16:41:45 2009
* Integrated original release back into main code base.
* SL 3 Sat Sep 12 17:58:20 2009
* Added display re-enable to VGA blank routine and comments
* on other VirtualPC->QEMU migration changes.
* SL 4 Sat Sep 10 20:43:47 2011
* Modified for MP2 F11 adventure game.
* SL 5 Sat Sep 14 16:13:20 2011
* Split fill_palette by mode and cleaned up code for release.
*/
#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <sys/io.h>
#include <sys/mman.h>
#include <unistd.h>
#include "types.h"
#include "photo.h"
#include "photo_headers.h"
#include "modex.h"
#include "text.h"
/*
* Calculate the image build buffer parameters. SCROLL_SIZE is the space
* needed for one plane of an image. SCREEN_SIZE is the space needed for
* all four planes. The extra +1 supports logical view x coordinates that
* are not multiples of four. In these cases, some plane addresses are
* shifted by 1 byte forward. The planes are stored in the build buffer
* in reverse order to allow those planes that shift forward to do so
* without running into planes that aren't shifted. For example, when
* the leftmost x pixel in the logical view is 3 mod 4, planes 2, 1, and 0
* are shifted forward, while plane 3 is not, so there is one unused byte
* between the image of plane 3 and that of plane 2. BUILD_BUF_SIZE is
* the size of the space allocated for building images. We add 20000 bytes
* to reduce the number of memory copies required during scrolling.
* Strictly speaking(try it), no extra space is necessary, but the minimum
* means an extra 64kB memory copy with every scroll pixel. Finally,
* BUILD_BASE_INIT places initial(or transferred) logical view in the
* middle of the available buffer area.
*/
#define SCROLL_SIZE (SCROLL_X_WIDTH * SCROLL_Y_DIM)
#define SCREEN_SIZE (SCROLL_SIZE * 4 + 1)
#define BUILD_BUF_SIZE (SCREEN_SIZE + 20000)
#define BUILD_BASE_INIT ((BUILD_BUF_SIZE - SCREEN_SIZE) / 2)
/* Mode X and general VGA parameters */
#define VID_MEM_SIZE 131072
#define MODE_X_MEM_SIZE 65536
#define NUM_SEQUENCER_REGS 5
#define NUM_CRTC_REGS 25
#define NUM_GRAPHICS_REGS 9
#define NUM_ATTR_REGS 22
/* Status Bar parameters */
#define STATUS_BAR_SIZE 1440 //Status Bar size in 4 plane buffer
#define MSG_MAX 20 //Message Max Length
#define STAT_MIDDLE 20 //Status Bar Middle Index
#define STAT_MAX 40 //Status Bar Max String Length
#define STATUS_COLOR 0x14 //Status Bar Color
/* VGA register settings for mode X */
static unsigned short mode_X_seq[NUM_SEQUENCER_REGS] = {
0x0100, 0x2101, 0x0F02, 0x0003, 0x0604
};
static unsigned short mode_X_CRTC[NUM_CRTC_REGS] = {
0x5F00, 0x4F01, 0x5002, 0x8203, 0x5404, 0x8005, 0xBF06, 0x1F07,
0x0008, 0x0109, 0x000A, 0x000B, 0x000C, 0x000D, 0x000E, 0x000F,
0x9C10, 0x8E11, 0x8F12, 0x2813, 0x0014, 0x9615, 0xB916, 0xE317,
0x6C18
};
static unsigned char mode_X_attr[NUM_ATTR_REGS * 2] = {
0x00, 0x00, 0x01, 0x01, 0x02, 0x02, 0x03, 0x03,
0x04, 0x04, 0x05, 0x05, 0x06, 0x06, 0x07, 0x07,
0x08, 0x08, 0x09, 0x09, 0x0A, 0x0A, 0x0B, 0x0B,
0x0C, 0x0C, 0x0D, 0x0D, 0x0E, 0x0E, 0x0F, 0x0F,
0x10, 0x61, 0x11, 0x00, 0x12, 0x0F, 0x13, 0x00,
0x14, 0x00, 0x15, 0x00
};
static unsigned short mode_X_graphics[NUM_GRAPHICS_REGS] = {
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x4005, 0x0506, 0x0F07,
0xFF08
};
/* VGA register settings for text mode 3(color text) */
static unsigned short text_seq[NUM_SEQUENCER_REGS] = {
0x0100, 0x2001, 0x0302, 0x0003, 0x0204
};
static unsigned short text_CRTC[NUM_CRTC_REGS] = {
0x5F00, 0x4F01, 0x5002, 0x8203, 0x5504, 0x8105, 0xBF06, 0x1F07,
0x0008, 0x4F09, 0x0D0A, 0x0E0B, 0x000C, 0x000D, 0x000E, 0x000F,
0x9C10, 0x8E11, 0x8F12, 0x2813, 0x1F14, 0x9615, 0xB916, 0xA317,
0xFF18
};
static unsigned char text_attr[NUM_ATTR_REGS * 2] = {
0x00, 0x00, 0x01, 0x01, 0x02, 0x02, 0x03, 0x03,
0x04, 0x04, 0x05, 0x05, 0x06, 0x06, 0x07, 0x07,
0x08, 0x08, 0x09, 0x09, 0x0A, 0x0A, 0x0B, 0x0B,
0x0C, 0x0C, 0x0D, 0x0D, 0x0E, 0x0E, 0x0F, 0x0F,
0x10, 0x0C, 0x11, 0x00, 0x12, 0x0F, 0x13, 0x08,
0x14, 0x00, 0x15, 0x00
};
static unsigned short text_graphics[NUM_GRAPHICS_REGS] = {
0x0000, 0x0001, 0x0002, 0x0003, 0x0004, 0x1005, 0x0E06, 0x0007,
0xFF08
};
/* local functions--see function headers for details */
static int open_memory_and_ports();
static void VGA_blank(int blank_bit);
static void set_seq_regs_and_reset(unsigned short table[NUM_SEQUENCER_REGS], unsigned char val);
static void set_CRTC_registers(unsigned short table[NUM_CRTC_REGS]);
static void set_attr_registers(unsigned char table[NUM_ATTR_REGS * 2]);
static void set_graphics_registers(unsigned short table[NUM_GRAPHICS_REGS]);
static void fill_palette_mode_x();
static void fill_palette_text();
static void write_font_data();
static void set_text_mode_3(int clear_scr);
static void copy_image(unsigned char* img, unsigned short scr_addr);
static void copy_status(unsigned char* img, unsigned short scr_addr);
/*
* Images are built in this buffer, then copied to the video memory.
* Copying to video memory with REP MOVSB is vastly faster than anything
* else with emulation, probably because it is a single instruction
* and translates to a native loop. It's also a pretty good technique
* in normal machines(albeit not as elegant as some others for reducing
* the number of video memory writes; unfortunately, these techniques
* are slower in emulation...).
*
* The size allows the four plane images to move within an area of
* about twice the size necessary(to reduce the need to deal with
* the boundary conditions by moving the data within the buffer).
*
* Plane 3 is first, followed by 2, 1, and 0. The reverse ordering
* is used because the logical address of 0 increases first; if plane
* 0 were first, we would need a buffer byte to keep it from colliding
* with plane 1 when plane 0 was offset by 1 from plane 1, i.e., when
* displaying a one-pixel left shift.
*
* The memory fence(included when NDEBUG is not defined) allocates
* the build buffer with extra space on each side. The extra space
* is filled with magic numbers(something unlikely to be written in
* error), and the fence areas are checked for those magic values at
* the end of the program to detect array access bugs(writes past
* the ends of the build buffer).
*/
#ifndef NDEBUG
#define MEM_FENCE_WIDTH 256
#else
#define MEM_FENCE_WIDTH 0
#endif
#define MEM_FENCE_MAGIC 0xF3
static unsigned char build[BUILD_BUF_SIZE + 2 * MEM_FENCE_WIDTH];
static int img3_off; /* offset of upper left pixel */
static unsigned char* img3; /* pointer to upper left pixel */
static int show_x, show_y; /* logical view coordinates */
/* displayed video memory variables */
static unsigned char* mem_image; /* pointer to start of video memory */
static unsigned short target_img; /* offset of displayed screen image */
/*
* functions provided by the caller to set_mode_X() and used to obtain
* graphic images of lines(pixels) to be mapped into the build buffer
* planes for display in mode X
*/
static void(*horiz_line_fn)(int, int, unsigned char[SCROLL_X_DIM]);
static void(*vert_line_fn)(int, int, unsigned char[SCROLL_Y_DIM]);
/*
* macro used to target a specific video plane or planes when writing
* to video memory in mode X; bits 8-11 in the mask_hi_bits enable writes
* to planes 0-3, respectively
*/
#define SET_WRITE_MASK(mask_hi_bits) \
do { \
asm volatile(" \n\
movw $0x03C4, %%dx /* set write mask */ \n\
movb $0x02, %b0 \n\
outw %w0, (%%dx) \n\
" \
: \
: "a"((mask_hi_bits)) \
: "edx", "memory" \
); \
} while (0)
/* macro used to write a byte to a port */
#define OUTB(port, val) \
do { \
asm volatile(" \n\
outb %b1, (%w0) \n\
" \
: /* no outputs */ \
: "d"((port)), "a"((val)) \
: "memory", "cc" \
); \
} while (0)
/* macro used to write two bytes to two consecutive ports */
#define OUTW(port, val) \
do { \
asm volatile(" \n\
outw %w1, (%w0) \n\
" \
: /* no outputs */ \
: "d"((port)), "a"((val)) \
: "memory", "cc" \
); \
} while (0)
/*
* macro used to write an array of two-byte values to two consecutive ports
*/
#define REP_OUTSW(port, source, count) \
do { \
asm volatile(" \n\
1: movw 0(%1), %%ax \n\
outw %%ax, (%w2) \n\
addl $2, %1 \n\
decl %0 \n\
jne 1b \n\
" \
: /* no outputs */ \
: "c"((count)), "S"((source)), "d"((port)) \
: "eax", "memory", "cc" \
); \
} while (0)
/*
* macro used to write an array of one-byte values to two consecutive ports
*/
#define REP_OUTSB(port, source, count) \
do { \
asm volatile(" \n\
1: movb 0(%1), %%al \n\
outb %%al, (%w2) \n\
incl %1 \n\
decl %0 \n\
jne 1b \n\
" \
: /* no outputs */ \
: "c"((count)), "S"((source)), "d"((port)) \
: "eax", "memory", "cc" \
); \
} while (0)
/*
* set_mode_X
* DESCRIPTION: Puts the VGA into mode X.
* INPUTS: horiz_fill_fn -- this function is used as a callback(by
* draw_horiz_line) to obtain a graphical
* image of a particular logical line for
* drawing to the build buffer
* vert_fill_fn -- this function is used as a callback(by
* draw_vert_line) to obtain a graphical
* image of a particular logical line for
* drawing to the build buffer
* OUTPUTS: none
* RETURN VALUE: 0 on success, -1 on failure
* SIDE EFFECTS: initializes the logical view window; maps video memory
* and obtains permission for VGA ports; clears video memory
*/
int set_mode_X(void(*horiz_fill_fn)(int, int, unsigned char[SCROLL_X_DIM]),
void(*vert_fill_fn)(int, int, unsigned char[SCROLL_Y_DIM])) {
int i; /* loop index for filling memory fence with magic numbers */
/*
* Record callback functions for obtaining horizontal and vertical
* line images.
*/
if (horiz_fill_fn == NULL || vert_fill_fn == NULL)
return -1;
horiz_line_fn = horiz_fill_fn;
vert_line_fn = vert_fill_fn;
/* Initialize the logical view window to position(0,0). */
show_x = show_y = 0;
img3_off = BUILD_BASE_INIT;
img3 = build + img3_off + MEM_FENCE_WIDTH;
/* Set up the memory fence on the build buffer. */
for (i = 0; i < MEM_FENCE_WIDTH; i++) {
build[i] = MEM_FENCE_MAGIC;
build[BUILD_BUF_SIZE + MEM_FENCE_WIDTH + i] = MEM_FENCE_MAGIC;
}
/* One display page goes at the start of video memory. */
target_img = 0x05A0;
/* Map video memory and obtain permission for VGA port access. */
if (open_memory_and_ports() == -1)
return -1;
/*
* The code below was produced by recording a call to set mode 0013h
* with display memory clearing and a windowed frame buffer, then
* modifying the code to set mode X instead. The code was then
* generalized into functions...
*
* modifications from mode 13h to mode X include...
* Sequencer Memory Mode Register: 0x0E to 0x06(0x3C4/0x04)
* Underline Location Register : 0x40 to 0x00(0x3D4/0x14)
* CRTC Mode Control Register : 0xA3 to 0xE3(0x3D4/0x17)
*/
VGA_blank(1); /* blank the screen */
set_seq_regs_and_reset(mode_X_seq, 0x63); /* sequencer registers */
set_CRTC_registers(mode_X_CRTC); /* CRT control registers */
set_attr_registers(mode_X_attr); /* attribute registers */
set_graphics_registers(mode_X_graphics); /* graphics registers */
fill_palette_mode_x(); /* palette colors */
clear_screens(); /* zero video memory */
VGA_blank(0); /* unblank the screen */
/* Return success. */
return 0;
}
/*
* clear_mode_X
* DESCRIPTION: Puts the VGA into text mode 3(color text).
* INPUTS: none
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: restores font data to video memory; clears screens;
* unmaps video memory; checks memory fence integrity
*/
void clear_mode_X() {
int i; /* loop index for checking memory fence */
/* Put VGA into text mode, restore font data, and clear screens. */
set_text_mode_3(1);
/* Unmap video memory. */
(void)munmap(mem_image, VID_MEM_SIZE);
/* Check validity of build buffer memory fence. Report breakage. */
for (i = 0; i < MEM_FENCE_WIDTH; i++) {
if (build[i] != MEM_FENCE_MAGIC) {
puts("lower build fence was broken");
break;
}
}
for (i = 0; i < MEM_FENCE_WIDTH; i++) {
if (build[BUILD_BUF_SIZE + MEM_FENCE_WIDTH + i] != MEM_FENCE_MAGIC) {
puts("upper build fence was broken");
break;
}
}
}
/*
* set_view_window
* DESCRIPTION: Set the logical view window, moving its location within
* the build buffer if necessary to keep all on-screen data
* in the build buffer. If the location within the build
* buffer moves, this function copies all data from the old
* window that are within the new screen to the appropriate
* new location, so only data not previously on the screen
* must be drawn before calling show_screen.
* INPUTS:(scr_x,scr_y) -- new upper left pixel of logical view window
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: may shift position of logical view window within build
* buffer
*/
void set_view_window(int scr_x, int scr_y) {
int old_x, old_y; /* old position of logical view window */
int start_x, start_y; /* starting position for copying from old to new */
int end_x, end_y; /* ending position for copying from old to new */
int start_off; /* offset of copy start relative to old build buffer start position */
int length; /* amount of data to be copied */
int i; /* copy loop index */
unsigned char* start_addr; /* starting memory address of copy */
unsigned char* target_addr; /* destination memory address for copy */
/* Record the old position. */
old_x = show_x;
old_y = show_y;
/* Keep track of the new view window. */
show_x = scr_x;
show_y = scr_y;
/*
* If the new view window fits within the boundaries of the build
* buffer, we need move nothing around.
*/
if (img3_off + (scr_x >> 2) + scr_y * SCROLL_X_WIDTH >= 0 &&
img3_off + 3 * SCROLL_SIZE + ((scr_x + SCROLL_X_DIM - 1) >> 2) +
(scr_y + SCROLL_Y_DIM - 1) * SCROLL_X_WIDTH < BUILD_BUF_SIZE)
return;
/*
* If the new screen does not overlap at all with the old screen, none
* of the old data need to be saved, and we can simply reposition the
* valid window of the build buffer in the middle of that buffer.
*/
if (scr_x <= old_x - SCROLL_X_DIM || scr_x >= old_x + SCROLL_X_DIM ||
scr_y <= old_y - SCROLL_Y_DIM || scr_y >= old_y + SCROLL_Y_DIM) {
img3_off = BUILD_BASE_INIT -(scr_x >> 2) - scr_y * SCROLL_X_WIDTH;
img3 = build + img3_off + MEM_FENCE_WIDTH;
return;
}
/*
* Any still-visible portion of the old screen should be retained.
* Rather than clipping exactly, we copy all contiguous data between
* a clipped starting point to a clipped ending point(which may
* include non-visible data).
*
* The starting point is the maximum(x,y) coordinates between the
* new and old screens. The ending point is the minimum(x,y)
* coordinates between the old and new screens(offset by the screen
* size).
*/
if (scr_x > old_x) {
start_x = scr_x;
end_x = old_x;
}
else {
start_x = old_x;
end_x = scr_x;
}
end_x += SCROLL_X_DIM - 1;
if (scr_y > old_y) {
start_y = scr_y;
end_y = old_y;
}
else {
start_y = old_y;
end_y = scr_y;
}
end_y += SCROLL_Y_DIM - 1;
/*
* We now calculate the starting and ending addresses for the copy
* as well as the new offsets for use with the build buffer. The
* length to be copied is basically the ending offset minus the starting
* offset plus one(plus the three screens in between planes 3 and 0).
*/
start_off = (start_x >> 2) + start_y * SCROLL_X_WIDTH;
start_addr = img3 + start_off;
length = (end_x >> 2) + end_y * SCROLL_X_WIDTH + 1 - start_off + 3 * SCROLL_SIZE;
img3_off = BUILD_BASE_INIT -(show_x >> 2) - show_y * SCROLL_X_WIDTH;
img3 = build + img3_off + MEM_FENCE_WIDTH;
target_addr = img3 + start_off;
/*
* Copy the relevant portion of the screen from the old location to the
* new one. The areas may overlap, so copy direction is important.
*(You should be able to explain why!)
*/
if (start_addr < target_addr) {
for (i = length; i-- > 0; ) {
target_addr[i] = start_addr[i];
}
}
else {
for (i = 0; i < length; i++) {
target_addr[i] = start_addr[i];
}
}
}
/*
* show_screen
* DESCRIPTION: Show the logical view window on the video display.
* INPUTS: none
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: copies from the build buffer to video memory;
* shifts the VGA display source to point to the new image
*/
void show_screen() {
unsigned char* addr; /* source address for copy */
int p_off; /* plane offset of first display plane */
int i; /* loop index over video planes */
/*
* Calculate offset of build buffer plane to be mapped into plane 0
* of display.
*/
p_off = (3 - (show_x & 3));
/* Switch to the other target screen in video memory. */
target_img ^= 0x4000;
/* Calculate the source address. */
addr = img3 + (show_x >> 2) + show_y * SCROLL_X_WIDTH;
/* Draw to each plane in the video memory. */
for (i = 0; i < 4; i++) {
SET_WRITE_MASK(1 << (i + 8));
copy_image(addr + ((p_off - i + 4) & 3) * SCROLL_SIZE + (p_off < i), target_img);
}
/*
* Change the VGA registers to point the top left of the screen
* to the video memory that we just filled.
*/
OUTW(0x03D4, (target_img & 0xFF00) | 0x0C);
OUTW(0x03D4, ((target_img & 0x00FF) << 8) | 0x0D);
}
/*
* show_statusbar
* DESCRIPTION: Show the logical view window on the video display.
* INPUTS: char* room_name, char* status_msg, char* typed
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: create status bar image and and buffer;
* copies from the build buffer to video memory;
* shifts the VGA display source to point to the new image
*/
void show_statusbar(const char* room_name, char* status_msg, const char* typed) {
unsigned char status_img[4*STATUS_BAR_SIZE]; /* create status bar image*/
unsigned char status_buf[4][STATUS_BAR_SIZE]; /* create status bar buffer*/
int i; /* loop index over status buffer*/
int j; /* loop index over video plane*/
int m; /* loop index for add space*/
int i_r, i_t ,i_m; /* loop index for room, typed and message*/
unsigned short target_stat = 0x0000; /* target buffer for status bar*/
char print_str[41] = {' '}; /* empty space base string*/
/* paint status bar*/
for(i = 0; i < STATUS_BAR_SIZE*4; i++){
status_img[i] = STATUS_COLOR;
}
/* full with space*/
for(m = 0; m < STAT_MAX; m++){
print_str[m] = ' ';
}
/* output string for no status_msg*/
if('\0' == status_msg[0]){
int len_room = strlen(room_name);
int len_type = strlen(typed);
for(i_r = 0; i_r < len_room; i_r++){
print_str[i_r] = room_name[i_r];
}
/* check typed length */
if(len_type < MSG_MAX){
print_str[39] = '_'; // print msg with "_" at the end index 39
int start_idx = 39 - len_type; //calculate start_idx for msg shorter than MSG_MAX
for(i_t = start_idx; i_t < start_idx+len_type; i_t ++){
print_str[i_t] = typed[i_t-start_idx];
}
}else if(len_type >= MSG_MAX){
for(i_t = STAT_MIDDLE; i_t < STAT_MAX; i_t++){ //print msg without "_"
print_str[i_t] = typed[i_t-STAT_MIDDLE];
}
}
/* output string for status_msg*/
}else{
int mid_offset = (STAT_MAX - strlen(status_msg))/2; //calculate front offset for status_msg stay at middle
for(i_m = 0; i_m < strlen(status_msg); i_m++){
print_str[i_m+mid_offset] = status_msg[i_m];
}
}
/* call the text_to_graph to create image for output string*/
text_to_graph(status_img, print_str);
/* call the graph_to_buffer to create build buffer for image*/
graph_to_buffer(status_img, status_buf);
/* copy status bar build buffer to video mem */
for (j = 0; j < 4; j++) {
SET_WRITE_MASK(1 << (j + 8));
copy_status(status_buf[j] , target_stat);
}
/*
* Change the VGA registers to point the top left of the screen
* to the video memory that we just filled.
*/
OUTW(0x03D4, (target_img & 0xFF00) | 0x0C);
OUTW(0x03D4, ((target_img & 0x00FF) << 8) | 0x0D);
}
/*
* graph_to_buffer
* DESCRIPTION: convert image to build buffer with 4 planes
* INPUTS: unsigned char* image, unsigned char buf[4][1440]
* OUTPUTS: none
* RETURN VALUE: none
*/
void graph_to_buffer(unsigned char* img, unsigned char buf[4][1440]){
int i; //Loop index for all pixel of status bar
int add_idx; //The index for each group of 4 plane pixels
for(i = 0; i < STATUS_BAR_SIZE*4; i++){
add_idx = i/4;
buf[0][add_idx] = img[add_idx*4];
buf[1][add_idx] = img[add_idx*4+1];
buf[2][add_idx] = img[add_idx*4+2];
buf[3][add_idx] = img[add_idx*4+3];
}
}
/*
* clear_screens
* DESCRIPTION: Fills the video memory with zeroes.
* INPUTS: none
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: fills all 256kB of VGA video memory with zeroes
*/
void clear_screens() {
/* Write to all four planes at once. */
SET_WRITE_MASK(0x0F00);
/* Set 64kB to zero(times four planes = 256kB). */
memset(mem_image, 0, MODE_X_MEM_SIZE);
}
/*
* The functions inside the preprocessor block below rely on functions
* in maze.c to generate graphical images of the maze. These functions
* are neither available nor necessary for the text restoration program
* based on this file, and are omitted to simplify linking that program.
*/
#ifndef TEXT_RESTORE_PROGRAM
/*
* draw_vert_line
* DESCRIPTION: Draw a vertical map line into the build buffer. The
* line should be offset from the left side of the logical
* view window screen by the given number of pixels.
* INPUTS: x -- the 0-based pixel column number of the line to be drawn
* within the logical view window (equivalent to the number
* of pixels from the leftmost pixel to the line to be
* drawn)
* OUTPUTS: none
* RETURN VALUE: Returns 0 on success. If x is outside of the valid
* SCROLL range, the function returns -1.
* SIDE EFFECTS: draws into the build buffer
*/
int draw_vert_line(int x) {
/* to be written... */
unsigned char buf[SCROLL_Y_DIM]; /* buffer for graphical image of line */
unsigned char* addr; /* address of first pixel in build buffer (without plane offset) */
int p_off; /* offset of plane of first pixel */
int i; /* loop index over pixels */
/* Check whether requested line falls in the logical view window. */
if (x < 0 || x >= SCROLL_X_DIM)
return -1;
/* Adjust y to the logical row value. */
x += show_x;
/* Get the image of the line. */
(*vert_line_fn)(x, show_y, buf);
/* Calculate starting address in build buffer. */
addr = img3 + (x >> 2) + show_y * SCROLL_X_WIDTH;
/* Calculate plane offset of first pixel. */
p_off = (3 - (x & 3));
/* Copy image data into appropriate planes in build buffer. */
for (i = 0; i < SCROLL_Y_DIM; i++) {
addr[p_off * SCROLL_SIZE] = buf[i];
addr += SCROLL_X_WIDTH;
}
return 0;
}
/*
* draw_horiz_line
* DESCRIPTION: Draw a horizontal map line into the build buffer. The
* line should be offset from the top of the logical view
* window screen by the given number of pixels.
* INPUTS: y -- the 0-based pixel row number of the line to be drawn
* within the logical view window (equivalent to the number
* of pixels from the top pixel to the line to be drawn)
* OUTPUTS: none
* RETURN VALUE: Returns 0 on success. If y is outside of the valid
* SCROLL range, the function returns -1.
* SIDE EFFECTS: draws into the build buffer
*/
int draw_horiz_line(int y) {
unsigned char buf[SCROLL_X_DIM]; /* buffer for graphical image of line */
unsigned char* addr; /* address of first pixel in build buffer (without plane offset) */
int p_off; /* offset of plane of first pixel */
int i; /* loop index over pixels */
/* Check whether requested line falls in the logical view window. */
if (y < 0 || y >= SCROLL_Y_DIM)
return -1;
/* Adjust y to the logical row value. */
y += show_y;
/* Get the image of the line. */
(*horiz_line_fn)(show_x, y, buf);
/* Calculate starting address in build buffer. */
addr = img3 + (show_x >> 2) + y * SCROLL_X_WIDTH;
/* Calculate plane offset of first pixel. */
p_off = (3 - (show_x & 3));
/* Copy image data into appropriate planes in build buffer. */
for (i = 0; i < SCROLL_X_DIM; i++) {
addr[p_off * SCROLL_SIZE] = buf[i];
if (--p_off < 0) {
p_off = 3;
addr++;
}
}
/* Return success. */
return 0;
}
#endif /* !defined(TEXT_RESTORE_PROGRAM) */
/*
* open_memory_and_ports
* DESCRIPTION: Map video memory into our address space; obtain permission
* to access VGA ports.
* INPUTS: none
* OUTPUTS: none
* RETURN VALUE: 0 on success, -1 on failure
* SIDE EFFECTS: prints an error message to stdout on failure
*/
static int open_memory_and_ports() {
int mem_fd; /* file descriptor for physical memory image */
/* Obtain permission to access ports 0x03C0 through 0x03DA. */
if (ioperm(0x03C0, 0x03DA - 0x03C0 + 1, 1) == -1) {
perror("set port permissions");
return -1;
}
/* Open file to access physical memory. */
if ((mem_fd = open("/dev/mem", O_RDWR)) == -1) {
perror("open /dev/mem");
return -1;
}
/* Map video memory(0xA0000 - 0xBFFFF) into our address space. */
if ((mem_image = mmap(0, VID_MEM_SIZE, PROT_READ | PROT_WRITE,
MAP_SHARED, mem_fd, 0xA0000)) == MAP_FAILED) {
perror("mmap video memory");
return -1;
}
/* Close /dev/mem file descriptor and return success. */
(void)close(mem_fd);
return 0;
}
/*
* VGA_blank
* DESCRIPTION: Blank or unblank the VGA display.
* INPUTS: blank_bit -- set to 1 to blank, 0 to unblank
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: none
*/
static void VGA_blank(int blank_bit) {
/*
* Move blanking bit into position for VGA sequencer register
*(index 1).
*/
blank_bit = ((blank_bit & 1) << 5);
asm volatile(" \n\
movb $0x01, %%al /* Set sequencer index to 1 */ \n\
movw $0x03C4, %%dx \n\
outb %%al, (%%dx) \n\
incw %%dx \n\
inb (%%dx), %%al /* Read old value */ \n\
andb $0xDF, %%al /* Calculate new value */ \n\
orl %0,%%eax \n\
outb %%al, (%%dx) /* Write new value */ \n\
movw $0x03DA, %%dx /* Enable display(0x20->P[0x3C0]) */ \n\
inb (%%dx), %%al /* Set attr reg state to index */ \n\
movw $0x03C0, %%dx /* Write index 0x20 to enable */ \n\
movb $0x20, %%al \n\
outb %%al, (%%dx) \n\
"
:
: "g"(blank_bit)
: "eax", "edx", "memory"
);
}
/*
* set_seq_regs_and_reset
* DESCRIPTION: Set VGA sequencer registers and miscellaneous output
* register; array of registers should force a reset of
* the VGA sequencer, which is restored to normal operation
* after a brief delay.
* INPUTS: table -- table of sequencer register values to use
* val -- value to which miscellaneous output register should be set
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: none
*/
static void set_seq_regs_and_reset(unsigned short table[NUM_SEQUENCER_REGS], unsigned char val) {
/*
* Dump table of values to sequencer registers. Includes forced reset
* as well as video blanking.
*/
REP_OUTSW(0x03C4, table, NUM_SEQUENCER_REGS);
/* Delay a bit... */
{ volatile int ii; for (ii = 0; ii < 10000; ii++); }
/* Set VGA miscellaneous output register. */
OUTB(0x03C2, val);
/* Turn sequencer on(array values above should always force reset). */
OUTW(0x03C4, 0x0300);
}
/*
* set_CRTC_registers
* DESCRIPTION: Set VGA cathode ray tube controller(CRTC) registers.
* INPUTS: table -- table of CRTC register values to use
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: none
*/
static void set_CRTC_registers(unsigned short table[NUM_CRTC_REGS]) {
/* clear protection bit to enable write access to first few registers */
OUTW(0x03D4, 0x0011);
REP_OUTSW(0x03D4, table, NUM_CRTC_REGS);
}
/*
* set_attr_registers
* DESCRIPTION: Set VGA attribute registers. Attribute registers use
* a single port and are thus written as a sequence of bytes
* rather than a sequence of words.
* INPUTS: table -- table of attribute register values to use
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: none
*/
static void set_attr_registers(unsigned char table[NUM_ATTR_REGS * 2]) {
/* Reset attribute register to write index next rather than data. */
asm volatile(" \n\
inb (%%dx), %%al \n\
"
:
: "d"(0x03DA)
: "eax", "memory"
);
REP_OUTSB(0x03C0, table, NUM_ATTR_REGS * 2);
}
/*
* set_graphics_registers
* DESCRIPTION: Set VGA graphics registers.
* INPUTS: table -- table of graphics register values to use
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: none
*/
static void set_graphics_registers(unsigned short table[NUM_GRAPHICS_REGS]) {
REP_OUTSW(0x03CE, table, NUM_GRAPHICS_REGS);
}
/*
* fill_palette_mode_x
* DESCRIPTION: Fill VGA palette with necessary colors for the adventure
* game. Only the first 64(of 256) colors are written.
* INPUTS: none
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: changes the first 64 palette colors
*/
static void fill_palette_mode_x() {
/* 6-bit RGB(red, green, blue) values for first 64 colors */
/* these are coded for 2 bits red, 2 bits green, 2 bits blue */
static unsigned char palette_RGB[64][3] = {
{0x00, 0x00, 0x00}, {0x00, 0x00, 0x15},
{0x00, 0x00, 0x2A}, {0x00, 0x00, 0x3F},
{0x00, 0x15, 0x00}, {0x00, 0x15, 0x15},
{0x00, 0x15, 0x2A}, {0x00, 0x15, 0x3F},
{0x00, 0x2A, 0x00}, {0x00, 0x2A, 0x15},
{0x00, 0x2A, 0x2A}, {0x00, 0x2A, 0x3F},
{0x00, 0x3F, 0x00}, {0x00, 0x3F, 0x15},
{0x00, 0x3F, 0x2A}, {0x00, 0x3F, 0x3F},
{0x15, 0x00, 0x00}, {0x15, 0x00, 0x15},
{0x15, 0x00, 0x2A}, {0x15, 0x00, 0x3F},
{0x15, 0x15, 0x00}, {0x15, 0x15, 0x15},
{0x15, 0x15, 0x2A}, {0x15, 0x15, 0x3F},
{0x15, 0x2A, 0x00}, {0x15, 0x2A, 0x15},
{0x15, 0x2A, 0x2A}, {0x15, 0x2A, 0x3F},
{0x15, 0x3F, 0x00}, {0x15, 0x3F, 0x15},
{0x15, 0x3F, 0x2A}, {0x15, 0x3F, 0x3F},
{0x2A, 0x00, 0x00}, {0x2A, 0x00, 0x15},
{0x2A, 0x00, 0x2A}, {0x2A, 0x00, 0x3F},
{0x2A, 0x15, 0x00}, {0x2A, 0x15, 0x15},
{0x2A, 0x15, 0x2A}, {0x2A, 0x15, 0x3F},
{0x2A, 0x2A, 0x00}, {0x2A, 0x2A, 0x15},
{0x2A, 0x2A, 0x2A}, {0x2A, 0x2A, 0x3F},
{0x2A, 0x3F, 0x00}, {0x2A, 0x3F, 0x15},
{0x2A, 0x3F, 0x2A}, {0x2A, 0x3F, 0x3F},
{0x3F, 0x00, 0x00}, {0x3F, 0x00, 0x15},
{0x3F, 0x00, 0x2A}, {0x3F, 0x00, 0x3F},
{0x3F, 0x15, 0x00}, {0x3F, 0x15, 0x15},
{0x3F, 0x15, 0x2A}, {0x3F, 0x15, 0x3F},
{0x3F, 0x2A, 0x00}, {0x3F, 0x2A, 0x15},
{0x3F, 0x2A, 0x2A}, {0x3F, 0x2A, 0x3F},
{0x3F, 0x3F, 0x00}, {0x3F, 0x3F, 0x15},
{0x3F, 0x3F, 0x2A}, {0x3F, 0x3F, 0x3F}
};
/* Start writing at color 0. */
OUTB(0x03C8, 0x00);
/* Write all 64 colors from array. */
REP_OUTSB(0x03C9, palette_RGB, 64 * 3);
}
/*
* fill_palette_octree
* DESCRIPTION: Fill VGA palette with necessary colors for the adventure
* game. Rest of 256 colors(192) are written.
* INPUTS: none
* OUTPUTS: none
* RETURN VALUE: none
* SIDE EFFECTS: changes the first 64 palette colors
*/
void fill_palette_octree(unsigned char * p) {
/* Start writing at color 64. */
OUTB(0x03C8, 0x40);
/* Write all 192 colors from array. */
REP_OUTSB(0x03C9, p, 192 * 3);
}