sys/src/games/gb/gb.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include <draw.h>
   4 #include <thread.h>
   5 #include <mouse.h>
   6 #include <cursor.h>
   7 #include <keyboard.h>
   8 #include "dat.h"
   9 #include "fns.h"
  10
  11 uchar *cart, *ram;
  12 int mbc, rombanks, rambanks, clock, ppuclock, divclock, timerclock, syncclock, syncfreq, sleeps, checkclock, msgclock, timerfreq, timer, keys, savefd, savereq, loadreq, scale, paused;
  13 Rectangle picr;
  14 Image *bg, *tmp;
  15 Mousectl *mc;
  16 QLock pauselock;
  17
  18 void
  19 message(char *fmt, ...)
  20 {
  21         va_list va;
  22         char buf[512];
  23
  24         va_start(va, fmt);
  25         vsnprint(buf, sizeof buf, fmt, va);
  26         string(screen, Pt(10, 10), display->black, ZP, display->defaultfont, buf);
  27         msgclock = CPUFREQ;
  28         va_end(va);
  29 }
  30
  31 void
  32 loadrom(char *file)
  33 {
  34         int fd, i;
  35         vlong len;
  36         u8int ck;
  37         char buf[512];
  38         char title[17];
  39         Point p;
  40         char *s;
  41         extern int battery, ramen;
  42
  43         fd = open(file, OREAD);
  44         if(fd < 0)
  45                 sysfatal("open: %r");
  46         len = seek(fd, 0, 2);
  47         if(len < 0)
  48                 sysfatal("seek: %r");
  49         if(len == 0 || len > 16*1048576)
  50                 sysfatal("are you sure this is a ROM?");
  51         cart = malloc(len);
  52         if(cart == nil)
  53                 sysfatal("malloc: %r");
  54         seek(fd, 0, 0);
  55         if(readn(fd, cart, len) < len)
  56                 sysfatal("read: %r");
  57         close(fd);
  58
  59         ck = 0;
  60         for(i = 0x134; i <= 0x14C; i++)
  61                 ck -= cart[i] + 1;
  62         if(ck != cart[0x14D])
  63                 sysfatal("checksum mismatch: %.2x != %.2x", ck, cart[0x14D]);
  64         memcpy(mem, cart, 32768);
  65         memset(title, 0, sizeof(title));
  66         memcpy(title, cart+0x134, 16);
  67         battery = 0;
  68         switch(cart[0x147]){
  69         case 0x09:
  70                 battery = 1;
  71         case 0x08:
  72                 ramen = 1;
  73         case 0x00:
  74                 mbc = 0;
  75                 break;
  76         case 0x03:
  77                 battery = 1;
  78         case 0x01: case 0x02:
  79                 mbc = 1;
  80                 break;
  81         case 0x06:
  82                 battery = 1;
  83         case 0x05:
  84                 mbc = 2;
  85                 break;
  86         case 0x0F: case 0x10: case 0x13:
  87                 battery = 1;
  88         case 0x11: case 0x12:
  89                 mbc = 3;
  90                 break;
  91         case 0x1B: case 0x1E:
  92                 battery = 1;
  93         case 0x19: case 0x1A: case 0x1C: case 0x1D:
  94                 mbc = 5;
  95                 break;
  96         default:
  97                 sysfatal("%s: unknown cartridge type %.2x", file, cart[0x147]);
  98         }
  99
 100         switch(cart[0x148]){
 101         case 0: case 1: case 2:
 102         case 3: case 4: case 5:
 103         case 6: case 7:
 104                 rombanks = 2 << (uint)cart[0x148];
 105                 break;
 106         case 52:
 107                 rombanks = 72;
 108                 break;
 109         case 53:
 110                 rombanks = 80;
 111                 break;
 112         case 54:
 113                 rombanks = 96;
 114                 break;
 115         default:
 116                 sysfatal("header field 0x148 (%.2x) invalid", cart[0x148]);
 117         }
 118         switch(cart[0x149]){
 119         case 0:
 120                 if(mbc != 2){
 121                         rambanks = 0;
 122                         break;
 123                 }
 124                 /*fallthrough*/
 125         case 1: case 2:
 126                 rambanks = 1;
 127                 break;
 128         case 3:
 129                 rambanks = 4;
 130                 break;
 131         default:
 132                 sysfatal("header field 0x149 (%.2x) invalid", cart[0x149]);
 133         }
 134         if(rambanks > 0){
 135                 ram = mallocz(rambanks * 8192, 1);
 136                 if(ram == nil)
 137                         sysfatal("malloc: %r");
 138         }
 139         if(len < rombanks * 0x4000)
 140                 sysfatal("cartridge image is too small, %.4x < %.4x", (int)len, rombanks * 0x4000);
 141         initdraw(nil, nil, title);
 142         originwindow(screen, Pt(0, 0), screen->r.min);
 143         p = divpt(addpt(screen->r.min, screen->r.max), 2);
 144         picr = (Rectangle){subpt(p, Pt(scale * 80, scale * 72)), addpt(p, Pt(scale * 80, scale * 72))};
 145         bg = allocimage(display, Rect(0, 0, 1, 1), screen->chan, 1, 0xCCCCCCFF);
 146         if(screen->chan != XRGB32 || screen->chan != XBGR32)
 147                 tmp = allocimage(display, Rect(0, 0, scale * 160, scale * 144), XRGB32, 0, 0);
 148         draw(screen, screen->r, bg, nil, ZP);
 149
 150         if(ram && battery){
 151                 strncpy(buf, file, sizeof buf - 4);
 152                 s = buf + strlen(buf) - 3;
 153                 if(s < buf || strcmp(s, ".gb") != 0)
 154                         s += 3;
 155                 strcpy(s, ".gbs");
 156                 savefd = create(buf, ORDWR|OEXCL, 0666);
 157                 if(savefd < 0)
 158                         savefd = open(buf, ORDWR);
 159                 if(savefd < 0)
 160                         message("open: %r");
 161                 else
 162                         readn(savefd, ram, rambanks * 8192);
 163                 atexit(flushram);
 164         }
 165 }
 166
 167 void
 168 keyproc(void *)
 169 {
 170         int fd;
 171         char buf[256], *s;
 172         Rune r;
 173
 174         fd = open("/dev/kbd", OREAD);
 175         if(fd < 0)
 176                 sysfatal("open: %r");
 177         for(;;){
 178                 if(read(fd, buf, 256) <= 0)
 179                         sysfatal("read /dev/kbd: %r");
 180                 if(buf[0] == 'c'){
 181                         if(utfrune(buf, Kdel))
 182                                 threadexitsall(nil);
 183                         if(utfrune(buf, KF|5))
 184                                 savereq = 1;
 185                         if(utfrune(buf, KF|6))
 186                                 loadreq = 1;
 187                 }
 188                 if(buf[0] != 'k' && buf[0] != 'K')
 189                         continue;
 190                 s = buf + 1;
 191                 keys = 0;
 192                 while(*s != 0){
 193                         s += chartorune(&r, s);
 194                         switch(r){
 195                         case Kesc:
 196                                 if(paused)
 197                                         qunlock(&pauselock);
 198                                 else
 199                                         qlock(&pauselock);
 200                                 paused = !paused;
 201                                 break;
 202                         case Kdel:
 203                                 threadexitsall(nil);
 204                         case Kdown:
 205                                 keys |= 1<<3;
 206                                 break;
 207                         case Kup:
 208                                 keys |= 1<<2;
 209                                 break;
 210                         case Kleft:
 211                                 keys |= 1<<1;
 212                                 break;
 213                         case Kright:
 214                                 keys |= 1<<0;
 215                                 break;
 216                         case 'x':
 217                                 keys |= 1<<4;
 218                                 break;
 219                         case 'z':
 220                                 keys |= 1<<5;
 221                                 break;
 222                         case Kshift:
 223                                 keys |= 1<<6;
 224                                 break;
 225                         case 10:
 226                                 keys |= 1<<7;
 227                                 break;
 228                         }
 229                 }
 230         }
 231 }
 232
 233 void
 234 threadmain(int argc, char** argv)
 235 {
 236         int t;
 237         vlong old, new, diff;
 238         Mouse m;
 239         Point p;
 240
 241         scale = 1;
 242         ARGBEGIN{
 243         case 'a':
 244                 initaudio();
 245                 break;
 246         case '2':
 247                 scale = 2;
 248                 break;
 249         case '3':
 250                 scale = 3;
 251                 break;
 252         default:
 253                 sysfatal("unknown flag -%c", ARGC());
 254         }ARGEND;
 255         if(argc == 0)
 256                 sysfatal("argument missing");
 257         pc = 0x100;
 258         sp = 0xFFFE;
 259         R[rA] = 0x01;
 260         R[rC] = 0x13;
 261         R[rE] = 0xD8;
 262         R[rL] = 0x4D;
 263         R[rH] = 0x01;
 264         Fl = 0xB0;
 265         loadrom(argv[0]);
 266         mc = initmouse(nil, screen);
 267         if(mc == nil)
 268                 sysfatal("init mouse: %r");
 269         proccreate(keyproc, nil, 8192);
 270         syncfreq = CPUFREQ / 50;
 271         old = nsec();
 272         for(;;){
 273                 if(savereq){
 274                         savestate("gb.save");
 275                         savereq = 0;
 276                 }
 277                 if(loadreq){
 278                         loadstate("gb.save");
 279                         loadreq = 0;
 280                 }
 281                 if(paused){
 282                         qlock(&pauselock);
 283                         qunlock(&pauselock);
 284                 }
 285                 t = step();
 286                 clock += t;
 287                 ppuclock += t;
 288                 divclock += t;
 289                 timerclock += t;
 290                 syncclock += t;
 291                 checkclock += t;
 292                 if(ppuclock >= 456){
 293                         ppustep();
 294                         ppuclock -= 456;
 295                         while(nbrecv(mc->c, &m) > 0)
 296                                 ;
 297                         if(nbrecvul(mc->resizec) > 0){
 298                                 if(getwindow(display, Refnone) < 0)
 299                                         sysfatal("resize failed: %r");
 300                                 p = divpt(addpt(screen->r.min, screen->r.max), 2);
 301                                 picr = (Rectangle){subpt(p, Pt(scale * 80, scale * 72)), addpt(p, Pt(scale * 80, scale * 72))};
 302                                 bg = allocimage(display, Rect(0, 0, 1, 1), screen->chan, 1, 0xCCCCCCFF);
 303                         }
 304                 }
 305                 if(divclock >= 256){
 306                         mem[DIV]++;
 307                         divclock = 0;
 308                 }
 309                 if(timer && timerclock >= timerfreq){
 310                         mem[TIMA]++;
 311                         if(mem[TIMA] == 0){
 312                                 mem[TIMA] = mem[TMA];
 313                                 interrupt(INTTIMER);
 314                         }
 315                         timerclock = 0;
 316                 }
 317                 if(syncclock >= syncfreq){
 318                         sleep(10);
 319                         sleeps++;
 320                         syncclock = 0;
 321                 }
 322                 if(checkclock >= CPUFREQ){
 323                         new = nsec();
 324                         diff = new - old - sleeps * 10 * MILLION;
 325                         diff = BILLION - diff;
 326                         if(diff <= 0)
 327                                 syncfreq = CPUFREQ;
 328                         else
 329                                 syncfreq = ((vlong)CPUFREQ) * 10 * MILLION / diff;
 330                         old = new;
 331                         checkclock = 0;
 332                         sleeps = 0;
 333                 }
 334                 if(msgclock > 0){
 335                         msgclock -= t;
 336                         if(msgclock <= 0){
 337                                 draw(screen, screen->r, bg, nil, ZP);
 338                                 msgclock = 0;
 339                         }
 340                 }
 341         }
 342 }