src/video/ipod/SDL_ipodvideo.c
author Darren Alton <dalton@stevens.edu>
Tue, 10 Jun 2008 06:45:39 +0000
branchgsoc2008_nds
changeset 2669 e27bdcc80744
parent 1895 c121d94672cb
child 2698 e1da92da346c
permissions -rw-r--r--
First commit. Added header configs for DS as well as a Makefile. Initial work on framebuffer video driver, currently not functioning as desired.

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This library 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

#include <sys/types.h>
#include <sys/ioctl.h>

#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <termios.h>
#include <ctype.h>

#include <linux/vt.h>
#include <linux/kd.h>
#include <linux/keyboard.h>
#include <linux/fb.h>

#include "SDL_video.h"
#include "SDL_mouse.h"
#include "../SDL_sysvideo.h"
#include "../SDL_pixels_c.h"
#include "../../events/SDL_events_c.h"
#include "SDL_sysevents.h"
#include "SDL_ipodvideo.h"

#define _THIS SDL_VideoDevice *this

static int iPod_VideoInit(_THIS, SDL_PixelFormat * vformat);
static SDL_Rect **iPod_ListModes(_THIS, SDL_PixelFormat * format,
                                 Uint32 flags);
static SDL_Surface *iPod_SetVideoMode(_THIS, SDL_Surface * current,
                                      int width, int height, int bpp,
                                      Uint32 flags);
static int iPod_SetColors(_THIS, int firstcolor, int ncolors,
                          SDL_Color * colors);
static void iPod_UpdateRects(_THIS, int nrects, SDL_Rect * rects);
static void iPod_VideoQuit(_THIS);
static void iPod_PumpEvents(_THIS);

static long iPod_GetGeneration();

static int initd = 0;
static int kbfd = -1;
static int fbfd = -1;
static int oldvt = -1;
static int curvt = -1;
static int old_kbmode = -1;
static long generation = 0;
static struct termios old_termios, cur_termios;

FILE *dbgout;

#define LCD_DATA          0x10
#define LCD_CMD           0x08
#define IPOD_OLD_LCD_BASE 0xc0001000
#define IPOD_OLD_LCD_RTC  0xcf001110
#define IPOD_NEW_LCD_BASE 0x70003000
#define IPOD_NEW_LCD_RTC  0x60005010

static unsigned long lcd_base, lcd_rtc, lcd_width, lcd_height;

static long
iPod_GetGeneration()
{
    int i;
    char cpuinfo[256];
    char *ptr;
    FILE *file;

    if ((file = fopen("/proc/cpuinfo", "r")) != NULL) {
        while (fgets(cpuinfo, sizeof(cpuinfo), file) != NULL)
            if (SDL_strncmp(cpuinfo, "Revision", 8) == 0)
                break;
        fclose(file);
    }
    for (i = 0; !isspace(cpuinfo[i]); i++);
    for (; isspace(cpuinfo[i]); i++);
    ptr = cpuinfo + i + 2;

    return SDL_strtol(ptr, NULL, 10);
}

static int
iPod_Available()
{
    return 1;
}

static void
iPod_DeleteDevice(SDL_VideoDevice * device)
{
    free(device->hidden);
    free(device);
}

void
iPod_InitOSKeymap(_THIS)
{
}

static SDL_VideoDevice *
iPod_CreateDevice(int devindex)
{
    SDL_VideoDevice *this;

    this = (SDL_VideoDevice *) SDL_malloc(sizeof(SDL_VideoDevice));
    if (this) {
        memset(this, 0, sizeof *this);
        this->hidden = (struct SDL_PrivateVideoData *)
            SDL_malloc(sizeof(struct SDL_PrivateVideoData));
    }
    if (!this || !this->hidden) {
        SDL_OutOfMemory();
        if (this)
            SDL_free(this);
        return 0;
    }
    memset(this->hidden, 0, sizeof(struct SDL_PrivateVideoData));

    generation = iPod_GetGeneration();

    this->VideoInit = iPod_VideoInit;
    this->ListModes = iPod_ListModes;
    this->SetVideoMode = iPod_SetVideoMode;
    this->SetColors = iPod_SetColors;
    this->UpdateRects = iPod_UpdateRects;
    this->VideoQuit = iPod_VideoQuit;
    this->AllocHWSurface = 0;
    this->CheckHWBlit = 0;
    this->FillHWRect = 0;
    this->SetHWColorKey = 0;
    this->SetHWAlpha = 0;
    this->LockHWSurface = 0;
    this->UnlockHWSurface = 0;
    this->FlipHWSurface = 0;
    this->FreeHWSurface = 0;
    this->SetCaption = 0;
    this->SetIcon = 0;
    this->IconifyWindow = 0;
    this->GrabInput = 0;
    this->GetWMInfo = 0;
    this->InitOSKeymap = iPod_InitOSKeymap;
    this->PumpEvents = iPod_PumpEvents;
    this->free = iPod_DeleteDevice;

    return this;
}

VideoBootStrap iPod_bootstrap = {
    "ipod", "iPod Framebuffer Driver",
    iPod_Available, iPod_CreateDevice
};

//--//

static int
iPod_VideoInit(_THIS, SDL_PixelFormat * vformat)
{
    if (!initd) {
        /*** Code adapted/copied from SDL fbcon driver. ***/

        static const char *const tty0[] = { "/dev/tty0", "/dev/vc/0", 0 };
        static const char *const vcs[] = { "/dev/vc/%d", "/dev/tty%d", 0 };
        int i, tty0_fd;

        dbgout =
            fdopen(open("/etc/sdlpod.log", O_WRONLY | O_SYNC | O_APPEND),
                   "a");
        if (dbgout) {
            setbuf(dbgout, 0);
            fprintf(dbgout, "--> Started SDL <--\n");
        }
        // Try to query for a free VT
        tty0_fd = -1;
        for (i = 0; tty0[i] && (tty0_fd < 0); ++i) {
            tty0_fd = open(tty0[i], O_WRONLY, 0);
        }
        if (tty0_fd < 0) {
            tty0_fd = dup(0);   /* Maybe stdin is a VT? */
        }
        ioctl(tty0_fd, VT_OPENQRY, &curvt);
        close(tty0_fd);

        tty0_fd = open("/dev/tty", O_RDWR, 0);
        if (tty0_fd >= 0) {
            ioctl(tty0_fd, TIOCNOTTY, 0);
            close(tty0_fd);
        }

        if ((geteuid() == 0) && (curvt > 0)) {
            for (i = 0; vcs[i] && (kbfd < 0); ++i) {
                char vtpath[12];

                SDL_snprintf(vtpath, SDL_arraysize(vtpath), vcs[i], curvt);
                kbfd = open(vtpath, O_RDWR);
            }
        }
        if (kbfd < 0) {
            if (dbgout)
                fprintf(dbgout, "Couldn't open any VC\n");
            return -1;
        }
        if (dbgout)
            fprintf(stderr, "Current VT: %d\n", curvt);

        if (kbfd >= 0) {
            /* Switch to the correct virtual terminal */
            if (curvt > 0) {
                struct vt_stat vtstate;

                if (ioctl(kbfd, VT_GETSTATE, &vtstate) == 0) {
                    oldvt = vtstate.v_active;
                }
                if (ioctl(kbfd, VT_ACTIVATE, curvt) == 0) {
                    if (dbgout)
                        fprintf(dbgout, "Waiting for switch to this VT... ");
                    ioctl(kbfd, VT_WAITACTIVE, curvt);
                    if (dbgout)
                        fprintf(dbgout, "done!\n");
                }
            }
            // Set terminal input mode
            if (tcgetattr(kbfd, &old_termios) < 0) {
                if (dbgout)
                    fprintf(dbgout, "Can't get termios\n");
                return -1;
            }
            cur_termios = old_termios;
            //      cur_termios.c_iflag &= ~(ICRNL | INPCK | ISTRIP | IXON);
            //      cur_termios.c_iflag |= (BRKINT);
            //      cur_termios.c_lflag &= ~(ICANON | ECHO | ISIG | IEXTEN);
            //      cur_termios.c_oflag &= ~(OPOST);
            //      cur_termios.c_oflag |= (ONOCR | ONLRET);
            cur_termios.c_lflag &= ~(ICANON | ECHO | ISIG);
            cur_termios.c_iflag &=
                ~(ISTRIP | IGNCR | ICRNL | INLCR | IXOFF | IXON);
            cur_termios.c_cc[VMIN] = 0;
            cur_termios.c_cc[VTIME] = 0;

            if (tcsetattr(kbfd, TCSAFLUSH, &cur_termios) < 0) {
                if (dbgout)
                    fprintf(dbgout, "Can't set termios\n");
                return -1;
            }
            if (ioctl(kbfd, KDSKBMODE, K_MEDIUMRAW) < 0) {
                if (dbgout)
                    fprintf(dbgout, "Can't set medium-raw mode\n");
                return -1;
            }
            if (ioctl(kbfd, KDSETMODE, KD_GRAPHICS) < 0) {
                if (dbgout)
                    fprintf(dbgout, "Can't set graphics\n");
                return -1;
            }
        }
        // Open the framebuffer
        if ((fbfd = open("/dev/fb0", O_RDWR)) < 0) {
            if (dbgout)
                fprintf(dbgout, "Can't open framebuffer\n");
            return -1;
        } else {
            struct fb_var_screeninfo vinfo;

            if (dbgout)
                fprintf(dbgout, "Generation: %ld\n", generation);

            if (generation >= 40000) {
                lcd_base = IPOD_NEW_LCD_BASE;
            } else {
                lcd_base = IPOD_OLD_LCD_BASE;
            }

            ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo);
            close(fbfd);

            if (lcd_base == IPOD_OLD_LCD_BASE)
                lcd_rtc = IPOD_OLD_LCD_RTC;
            else if (lcd_base == IPOD_NEW_LCD_BASE)
                lcd_rtc = IPOD_NEW_LCD_RTC;
            else {
                SDL_SetError("Unknown iPod version");
                return -1;
            }

            lcd_width = vinfo.xres;
            lcd_height = vinfo.yres;

            if (dbgout)
                fprintf(dbgout, "LCD is %dx%d\n", lcd_width, lcd_height);
        }

        fcntl(kbfd, F_SETFL, O_RDWR | O_NONBLOCK);

        /* Determine the current screen size */
        this->info.current_w = lcd_width;
        this->info.current_h = lcd_height;

        if ((generation >= 60000) && (generation < 70000)) {
            vformat->BitsPerPixel = 16;
            vformat->Rmask = 0xF800;
            vformat->Gmask = 0x07E0;
            vformat->Bmask = 0x001F;
        } else {
            vformat->BitsPerPixel = 8;
            vformat->Rmask = vformat->Gmask = vformat->Bmask = 0;
        }

        initd = 1;
        if (dbgout)
            fprintf(dbgout, "Initialized.\n\n");
    }
    return 0;
}

static SDL_Rect **
iPod_ListModes(_THIS, SDL_PixelFormat * format, Uint32 flags)
{
    int width, height, fd;
    static SDL_Rect r;
    static SDL_Rect *rs[2] = { &r, 0 };

    if ((fd = open("/dev/fb0", O_RDWR)) < 0) {
        return 0;
    } else {
        struct fb_var_screeninfo vinfo;

        ioctl(fbfd, FBIOGET_VSCREENINFO, &vinfo);
        close(fbfd);

        width = vinfo.xres;
        height = vinfo.yres;
    }
    r.x = r.y = 0;
    r.w = width;
    r.h = height;
    return rs;
}


static SDL_Surface *
iPod_SetVideoMode(_THIS, SDL_Surface * current, int width, int height,
                  int bpp, Uint32 flags)
{
    Uint32 Rmask, Gmask, Bmask;
    if (bpp > 8) {
        Rmask = 0xF800;
        Gmask = 0x07E0;
        Bmask = 0x001F;
    } else {
        Rmask = Gmask = Bmask = 0;
    }

    if (this->hidden->buffer)
        SDL_free(this->hidden->buffer);
    this->hidden->buffer = SDL_malloc(width * height * (bpp / 8));
    if (!this->hidden->buffer) {
        SDL_SetError("Couldn't allocate buffer for requested mode");
        return 0;
    }

    memset(this->hidden->buffer, 0, width * height * (bpp / 8));

    if (!SDL_ReallocFormat(current, bpp, Rmask, Gmask, Bmask, 0)) {
        SDL_SetError("Couldn't allocate new pixel format");
        SDL_free(this->hidden->buffer);
        this->hidden->buffer = 0;
        return 0;
    }

    if (bpp <= 8) {
        int i, j;
        for (i = 0; i < 256; i += 4) {
            for (j = 0; j < 4; j++) {
                current->format->palette->colors[i + j].r = 85 * j;
                current->format->palette->colors[i + j].g = 85 * j;
                current->format->palette->colors[i + j].b = 85 * j;
            }
        }
    }

    current->flags = flags & SDL_FULLSCREEN;
    this->hidden->w = current->w = width;
    this->hidden->h = current->h = height;
    current->pitch = current->w * (bpp / 8);
    current->pixels = this->hidden->buffer;

    return current;
}

static int
iPod_SetColors(_THIS, int firstcolor, int ncolors, SDL_Color * colors)
{
    if (SDL_VideoSurface && SDL_VideoSurface->format
        && SDL_VideoSurface->format->palette) {
        int i, j;
        for (i = 0; i < 256; i += 4) {
            for (j = 0; j < 4; j++) {
                SDL_VideoSurface->format->palette->colors[i + j].r = 85 * j;
                SDL_VideoSurface->format->palette->colors[i + j].g = 85 * j;
                SDL_VideoSurface->format->palette->colors[i + j].b = 85 * j;
            }
        }
    }
    return 0;
}

static void
iPod_VideoQuit(_THIS)
{
    ioctl(kbfd, KDSETMODE, KD_TEXT);
    tcsetattr(kbfd, TCSAFLUSH, &old_termios);
    old_kbmode = -1;

    if (oldvt > 0)
        ioctl(kbfd, VT_ACTIVATE, oldvt);

    if (kbfd > 0)
        close(kbfd);

    if (dbgout) {
        fprintf(dbgout, "<-- Ended SDL -->\n");
        fclose(dbgout);
    }

    kbfd = -1;
}

static char iPod_SC_keymap[] = {
    0,                          /* 0 - no key */
    '[' - 0x40,                 /* ESC (Ctrl+[) */
    '1', '2', '3', '4', '5', '6', '7', '8', '9',
    '-', '=',
    '\b', '\t',                 /* Backspace, Tab (Ctrl+H,Ctrl+I) */
    'q', 'w', 'e', 'r', 't', 'y', 'u', 'i', 'o', 'p', '[', ']',
    '\n', 0,                    /* Enter, Left CTRL */
    'a', 's', 'd', 'f', 'g', 'h', 'j', 'k', 'l', ';', '\'', '`',
    0, '\\',                    /* left shift, backslash */
    'z', 'x', 'c', 'v', 'b', 'n', 'm', ',', '.', '/',
    0, '*', 0, ' ', 0,          /* right shift, KP mul, left alt, space, capslock */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0,       /* F1-10 */
    0, 0,                       /* numlock, scrollock */
    '7', '8', '9', '-', '4', '5', '6', '+', '1', '2', '3', '0', '.',    /* numeric keypad */
    0, 0,                       /* padding */
    0, 0, 0,                    /* "less" (?), F11, F12 */
    0, 0, 0, 0, 0, 0, 0,        /* padding */
    '\n', 0, '/', 0, 0,         /* KP enter, Rctrl, Ctrl, KP div, PrtSc, RAlt */
    0, 0, 0, 0, 0, 0, 0, 0, 0,  /* Break, Home, Up, PgUp, Left, Right, End, Down, PgDn */
    0, 0,                       /* Ins, Del */
    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,      /* padding */
    0, 0,                       /* RWin, LWin */
    0                           /* no key */
};


static void
iPod_keyboard()
{
    unsigned char keybuf[128];
    int i, nread;
    SDL_keysym keysym;
    SDL_Event ev;

    keysym.mod = 0;
    keysym.scancode = 0xff;
    memset(&ev, 0, sizeof(SDL_Event));

    nread = read(kbfd, keybuf, 128);
    for (i = 0; i < nread; i++) {
        char ascii = iPod_SC_keymap[keybuf[i] & 0x7f];

        if (dbgout)
            fprintf(dbgout, "Key! %02x is %c %s", keybuf[i], ascii,
                    (keybuf[i] & 0x80) ? "up" : "down");

        keysym.sym = keysym.unicode = ascii;
        ev.type = (keybuf[i] & 0x80) ? SDL_KEYUP : SDL_KEYDOWN;
        ev.key.state = 0;
        ev.key.keysym = keysym;
        SDL_PushEvent(&ev);
    }
}

static void
iPod_PumpEvents(_THIS)
{
    fd_set fdset;
    int max_fd = 0;
    static struct timeval zero;
    int posted;

    do {
        posted = 0;

        FD_ZERO(&fdset);
        if (kbfd >= 0) {
            FD_SET(kbfd, &fdset);
            max_fd = kbfd;
        }
        if (dbgout)
            fprintf(dbgout, "Selecting");
        if (select(max_fd + 1, &fdset, 0, 0, &zero) > 0) {
            if (dbgout)
                fprintf(dbgout, " -> match!\n");
            iPod_keyboard();
            posted++;
        }
        if (dbgout)
            fprintf(dbgout, "\n");
    } while (posted);
}

// enough space for 160x128x2
static char ipod_scr[160 * (128 / 4)];

#define outl(datum,addr) (*(volatile unsigned long *)(addr) = (datum))
#define inl(addr) (*(volatile unsigned long *)(addr))

/*** The following LCD code is taken from Linux kernel uclinux-2.4.24-uc0-ipod2,
     file arch/armnommu/mach-ipod/fb.c. A few modifications have been made. ***/

/* get current usec counter */
static int
M_timer_get_current(void)
{
    return inl(lcd_rtc);
}

/* check if number of useconds has past */
static int
M_timer_check(int clock_start, int usecs)
{
    unsigned long clock;
    clock = inl(lcd_rtc);

    if ((clock - clock_start) >= usecs) {
        return 1;
    } else {
        return 0;
    }
}

/* wait for LCD with timeout */
static void
M_lcd_wait_write(void)
{
    if ((inl(lcd_base) & 0x8000) != 0) {
        int start = M_timer_get_current();

        do {
            if ((inl(lcd_base) & (unsigned int) 0x8000) == 0)
                break;
        } while (M_timer_check(start, 1000) == 0);
    }
}


/* send LCD data */
static void
M_lcd_send_data(int data_lo, int data_hi)
{
    M_lcd_wait_write();

    outl(data_lo, lcd_base + LCD_DATA);

    M_lcd_wait_write();

    outl(data_hi, lcd_base + LCD_DATA);

}

/* send LCD command */
static void
M_lcd_prepare_cmd(int cmd)
{
    M_lcd_wait_write();

    outl(0x0, lcd_base + LCD_CMD);

    M_lcd_wait_write();

    outl(cmd, lcd_base + LCD_CMD);

}

/* send LCD command and data */
static void
M_lcd_cmd_and_data(int cmd, int data_lo, int data_hi)
{
    M_lcd_prepare_cmd(cmd);

    M_lcd_send_data(data_lo, data_hi);
}

// Copied from uW
static void
M_update_display(int sx, int sy, int mx, int my)
{
    int y;
    unsigned short cursor_pos;

    sx >>= 3;
    mx >>= 3;

    cursor_pos = sx + (sy << 5);

    for (y = sy; y <= my; y++) {
        unsigned char *img_data;
        int x;

        /* move the cursor */
        M_lcd_cmd_and_data(0x11, cursor_pos >> 8, cursor_pos & 0xff);

        /* setup for printing */
        M_lcd_prepare_cmd(0x12);

        img_data = ipod_scr + (sx << 1) + (y * (lcd_width / 4));

        /* loops up to 160 times */
        for (x = sx; x <= mx; x++) {
            /* display eight pixels */
            M_lcd_send_data(*(img_data + 1), *img_data);

            img_data += 2;
        }

        /* update cursor pos counter */
        cursor_pos += 0x20;
    }
}

/* get current usec counter */
static int
C_timer_get_current(void)
{
    return inl(0x60005010);
}

/* check if number of useconds has past */
static int
C_timer_check(int clock_start, int usecs)
{
    unsigned long clock;
    clock = inl(0x60005010);

    if ((clock - clock_start) >= usecs) {
        return 1;
    } else {
        return 0;
    }
}

/* wait for LCD with timeout */
static void
C_lcd_wait_write(void)
{
    if ((inl(0x70008A0C) & 0x80000000) != 0) {
        int start = C_timer_get_current();

        do {
            if ((inl(0x70008A0C) & 0x80000000) == 0)
                break;
        } while (C_timer_check(start, 1000) == 0);
    }
}
static void
C_lcd_cmd_data(int cmd, int data)
{
    C_lcd_wait_write();
    outl(cmd | 0x80000000, 0x70008A0C);

    C_lcd_wait_write();
    outl(data | 0x80000000, 0x70008A0C);
}

static void
C_update_display(int sx, int sy, int mx, int my)
{
    int height = (my - sy) + 1;
    int width = (mx - sx) + 1;

    char *addr = SDL_VideoSurface->pixels;

    if (width & 1)
        width++;

    /* start X and Y */
    C_lcd_cmd_data(0x12, (sy & 0xff));
    C_lcd_cmd_data(0x13, (((SDL_VideoSurface->w - 1) - sx) & 0xff));

    /* max X and Y */
    C_lcd_cmd_data(0x15, (((sy + height) - 1) & 0xff));
    C_lcd_cmd_data(0x16,
                   (((((SDL_VideoSurface->w - 1) - sx) - width) + 1) & 0xff));

    addr += sx + sy * SDL_VideoSurface->pitch;

    while (height > 0) {
        int h, x, y, pixels_to_write;

        pixels_to_write = (width * height) * 2;

        /* calculate how much we can do in one go */
        h = height;
        if (pixels_to_write > 64000) {
            h = (64000 / 2) / width;
            pixels_to_write = (width * h) * 2;
        }

        outl(0x10000080, 0x70008A20);
        outl((pixels_to_write - 1) | 0xC0010000, 0x70008A24);
        outl(0x34000000, 0x70008A20);

        /* for each row */
        for (x = 0; x < h; x++) {
            /* for each column */
            for (y = 0; y < width; y += 2) {
                unsigned two_pixels;

                two_pixels = addr[0] | (addr[1] << 16);
                addr += 2;

                while ((inl(0x70008A20) & 0x1000000) == 0);

                /* output 2 pixels */
                outl(two_pixels, 0x70008B00);
            }

            addr += SDL_VideoSurface->w - width;
        }

        while ((inl(0x70008A20) & 0x4000000) == 0);

        outl(0x0, 0x70008A24);

        height = height - h;
    }
}

// Should work with photo. However, I don't have one, so I'm not sure.
static void
iPod_UpdateRects(_THIS, int nrects, SDL_Rect * rects)
{
    if (SDL_VideoSurface->format->BitsPerPixel == 16) {
        C_update_display(0, 0, lcd_width, lcd_height);
    } else {
        int i, y, x;
        for (i = 0; i < nrects; i++) {
            SDL_Rect *r = rects + i;
            if (!r) {
                continue;
            }

            for (y = r->y; (y < r->y + r->h) && y < lcd_height; y++) {
                for (x = r->x; (x < r->x + r->w) && x < lcd_width; x++) {
                    ipod_scr[y * (lcd_width / 4) + x / 4] &=
                        ~(3 << (2 * (x % 4)));
                    ipod_scr[y * (lcd_width / 4) + x / 4] |=
                        (((Uint8 *) (SDL_VideoSurface->pixels))[y *
                                                                SDL_VideoSurface->
                                                                pitch
                                                                +
                                                                x] &
                         3) << (2 * (x % 4));
                }
            }
        }

        M_update_display(0, 0, lcd_width, lcd_height);
    }
}

/* vi: set ts=4 sw=4 expandtab: */