src/glut/dos/PC_HW/pc_keyb.c

   1 /*
   2  * PC/HW routine collection v1.3 for DOS/DJGPP
   3  *
   4  *  Copyright (C) 2002 - Daniel Borca
   5  *  Email : dborca@yahoo.com
   6  *  Web   : http://www.geocities.com/dborca
   7  */
   8
   9
  10 #include <pc.h>
  11 #include <sys/exceptn.h>
  12 #include <sys/farptr.h>
  13
  14 #include "pc_hw.h"
  15
  16
  17 #define KEYB_IRQ 1
  18
  19 #define KEY_BUFFER_SIZE 64
  20
  21 #define KB_MODIFIERS (KB_SHIFT_FLAG | KB_CTRL_FLAG | KB_ALT_FLAG | KB_LWIN_FLAG | KB_RWIN_FLAG | KB_MENU_FLAG)
  22 #define KB_LED_FLAGS (KB_SCROLOCK_FLAG | KB_NUMLOCK_FLAG | KB_CAPSLOCK_FLAG)
  23
  24 static int keyboard_installed;
  25
  26 static volatile struct {
  27    volatile int start, end;
  28    volatile int key[KEY_BUFFER_SIZE];
  29 } key_buffer;
  30
  31 static volatile int key_enhanced, key_pause_loop, key_shifts;
  32 static int leds_ok = TRUE;
  33 static int in_a_terrupt = FALSE;
  34 static volatile char pc_key[KEY_MAX];
  35
  36
  37 /* convert Allegro format scancodes into key_shifts flag bits */
  38 static unsigned short modifier_table[KEY_MAX - KEY_MODIFIERS] = {
  39    KB_SHIFT_FLAG,    KB_SHIFT_FLAG,    KB_CTRL_FLAG,
  40    KB_CTRL_FLAG,     KB_ALT_FLAG,      KB_ALT_FLAG,
  41    KB_LWIN_FLAG,     KB_RWIN_FLAG,     KB_MENU_FLAG,
  42    KB_SCROLOCK_FLAG, KB_NUMLOCK_FLAG,  KB_CAPSLOCK_FLAG
  43 };
  44
  45
  46 /* lookup table for converting hardware scancodes into Allegro format */
  47 static unsigned char hw_to_mycode[128] = {
  48    /* 0x00 */  0,              KEY_ESC,        KEY_1,          KEY_2,
  49    /* 0x04 */  KEY_3,          KEY_4,          KEY_5,          KEY_6,
  50    /* 0x08 */  KEY_7,          KEY_8,          KEY_9,          KEY_0,
  51    /* 0x0C */  KEY_MINUS,      KEY_EQUALS,     KEY_BACKSPACE,  KEY_TAB,
  52    /* 0x10 */  KEY_Q,          KEY_W,          KEY_E,          KEY_R,
  53    /* 0x14 */  KEY_T,          KEY_Y,          KEY_U,          KEY_I,
  54    /* 0x18 */  KEY_O,          KEY_P,          KEY_OPENBRACE,  KEY_CLOSEBRACE,
  55    /* 0x1C */  KEY_ENTER,      KEY_LCONTROL,   KEY_A,          KEY_S,
  56    /* 0x20 */  KEY_D,          KEY_F,          KEY_G,          KEY_H,
  57    /* 0x24 */  KEY_J,          KEY_K,          KEY_L,          KEY_COLON,
  58    /* 0x28 */  KEY_QUOTE,      KEY_TILDE,      KEY_LSHIFT,     KEY_BACKSLASH,
  59    /* 0x2C */  KEY_Z,          KEY_X,          KEY_C,          KEY_V,
  60    /* 0x30 */  KEY_B,          KEY_N,          KEY_M,          KEY_COMMA,
  61    /* 0x34 */  KEY_STOP,       KEY_SLASH,      KEY_RSHIFT,     KEY_ASTERISK,
  62    /* 0x38 */  KEY_ALT,        KEY_SPACE,      KEY_CAPSLOCK,   KEY_F1,
  63    /* 0x3C */  KEY_F2,         KEY_F3,         KEY_F4,         KEY_F5,
  64    /* 0x40 */  KEY_F6,         KEY_F7,         KEY_F8,         KEY_F9,
  65    /* 0x44 */  KEY_F10,        KEY_NUMLOCK,    KEY_SCRLOCK,    KEY_7_PAD,
  66    /* 0x48 */  KEY_8_PAD,      KEY_9_PAD,      KEY_MINUS_PAD,  KEY_4_PAD,
  67    /* 0x4C */  KEY_5_PAD,      KEY_6_PAD,      KEY_PLUS_PAD,   KEY_1_PAD,
  68    /* 0x50 */  KEY_2_PAD,      KEY_3_PAD,      KEY_0_PAD,      KEY_DEL_PAD,
  69    /* 0x54 */  KEY_PRTSCR,     0,              KEY_BACKSLASH2, KEY_F11,
  70    /* 0x58 */  KEY_F12,        0,              0,              KEY_LWIN,
  71    /* 0x5C */  KEY_RWIN,       KEY_MENU,       0,              0,
  72    /* 0x60 */  0,              0,              0,              0,
  73    /* 0x64 */  0,              0,              0,              0,
  74    /* 0x68 */  0,              0,              0,              0,
  75    /* 0x6C */  0,              0,              0,              0,
  76    /* 0x70 */  KEY_KANA,       0,              0,              KEY_ABNT_C1,
  77    /* 0x74 */  0,              0,              0,              0,
  78    /* 0x78 */  0,              KEY_CONVERT,    0,              KEY_NOCONVERT,
  79    /* 0x7C */  0,              KEY_YEN,       0,              0
  80 };
  81
  82
  83 /* lookup table for converting extended hardware codes into Allegro format */
  84 static unsigned char hw_to_mycode_ex[128] = {
  85    /* 0x00 */  0,              KEY_ESC,        KEY_1,          KEY_2,
  86    /* 0x04 */  KEY_3,          KEY_4,          KEY_5,          KEY_6,
  87    /* 0x08 */  KEY_7,          KEY_8,          KEY_9,          KEY_0,
  88    /* 0x0C */  KEY_MINUS,      KEY_EQUALS,     KEY_BACKSPACE,  KEY_TAB,
  89    /* 0x10 */  KEY_CIRCUMFLEX, KEY_AT,         KEY_COLON2,     KEY_R,
  90    /* 0x14 */  KEY_KANJI,      KEY_Y,          KEY_U,          KEY_I,
  91    /* 0x18 */  KEY_O,          KEY_P,          KEY_OPENBRACE,  KEY_CLOSEBRACE,
  92    /* 0x1C */  KEY_ENTER_PAD,  KEY_RCONTROL,   KEY_A,          KEY_S,
  93    /* 0x20 */  KEY_D,          KEY_F,          KEY_G,          KEY_H,
  94    /* 0x24 */  KEY_J,          KEY_K,          KEY_L,          KEY_COLON,
  95    /* 0x28 */  KEY_QUOTE,      KEY_TILDE,      0,              KEY_BACKSLASH,
  96    /* 0x2C */  KEY_Z,          KEY_X,          KEY_C,          KEY_V,
  97    /* 0x30 */  KEY_B,          KEY_N,          KEY_M,          KEY_COMMA,
  98    /* 0x34 */  KEY_STOP,       KEY_SLASH_PAD,  0,              KEY_PRTSCR,
  99    /* 0x38 */  KEY_ALTGR,      KEY_SPACE,      KEY_CAPSLOCK,   KEY_F1,
 100    /* 0x3C */  KEY_F2,         KEY_F3,         KEY_F4,         KEY_F5,
 101    /* 0x40 */  KEY_F6,         KEY_F7,         KEY_F8,         KEY_F9,
 102    /* 0x44 */  KEY_F10,        KEY_NUMLOCK,    KEY_PAUSE,      KEY_HOME,
 103    /* 0x48 */  KEY_UP,         KEY_PGUP,       KEY_MINUS_PAD,  KEY_LEFT,
 104    /* 0x4C */  KEY_5_PAD,      KEY_RIGHT,      KEY_PLUS_PAD,   KEY_END,
 105    /* 0x50 */  KEY_DOWN,       KEY_PGDN,       KEY_INSERT,     KEY_DEL,
 106    /* 0x54 */  KEY_PRTSCR,     0,              KEY_BACKSLASH2, KEY_F11,
 107    /* 0x58 */  KEY_F12,        0,              0,              KEY_LWIN,
 108    /* 0x5C */  KEY_RWIN,       KEY_MENU,       0,              0,
 109    /* 0x60 */  0,              0,              0,              0,
 110    /* 0x64 */  0,              0,              0,              0,
 111    /* 0x68 */  0,              0,              0,              0,
 112    /* 0x6C */  0,              0,              0,              0,
 113    /* 0x70 */  0,              0,              0,              0,
 114    /* 0x74 */  0,              0,              0,              0,
 115    /* 0x78 */  0,              0,              0,              0,
 116    /* 0x7C */  0,              0,              0,              0
 117 };
 118
 119
 120 /* default mapping table for the US keyboard layout */
 121 static unsigned short standard_key_ascii_table[KEY_MAX] = {
 122    /* start */       0,
 123    /* alphabet */    'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
 124    /* numbers */     '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
 125    /* numpad */      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
 126    /* func keys */   0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 127    /* misc chars */  27, '`', '-', '=', 8, 9, '[', ']', 13, ';', '\'', '\\', '\\', ',', '.', '/', ' ',
 128    /* controls */    0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 129    /* numpad */      '/', '*', '-', '+', '.', 13,
 130    /* modifiers */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 131 };
 132
 133
 134 /* capslock mapping table for the US keyboard layout */
 135 static unsigned short standard_key_capslock_table[KEY_MAX] = {
 136    /* start */       0,
 137    /* alphabet */    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
 138    /* numbers */     '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
 139    /* numpad */      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
 140    /* func keys */   0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 141    /* misc chars */  27, '`', '-', '=', 8, 9, '[', ']', 13, ';', '\'', '\\', '\\', ',', '.', '/', ' ',
 142    /* controls */    0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 143    /* numpad */      '/', '*', '-', '+', '.', 13,
 144    /* modifiers */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 145 };
 146
 147
 148 /* shifted mapping table for the US keyboard layout */
 149 static unsigned short standard_key_shift_table[KEY_MAX] = {
 150    /* start */       0,
 151    /* alphabet */    'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
 152    /* numbers */     ')', '!', '@', '#', '$', '%', '^', '&', '*', '(',
 153    /* numpad */      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
 154    /* func keys */   0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 155    /* misc chars */  27, '~', '_', '+', 8, 9, '{', '}', 13, ':', '"', '|', '|', '<', '>', '?', ' ',
 156    /* controls */    0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 157    /* numpad */      '/', '*', '-', '+', '.', 13,
 158    /* modifiers */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 159 };
 160
 161
 162 /* ctrl+key mapping table for the US keyboard layout */
 163 static unsigned short standard_key_control_table[KEY_MAX] = {
 164    /* start */       0,
 165    /* alphabet */    1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,
 166    /* numbers */     2, 2, 2, 2, 2, 2, 2, 2, 2, 2,
 167    /* numpad */      '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
 168    /* func keys */   0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 169    /* misc chars */  27, 2, 2, 2, 127, 127, 2, 2, 10, 2, 2, 2, 2, 2, 2, 2, 2,
 170    /* controls */    0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF, 0xFFFF,
 171    /* numpad */      2, 2, 2, 2, 2, 10,
 172    /* modifiers */   0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
 173 };
 174
 175
 176 /* convert numeric pad scancodes into arrow codes */
 177 static unsigned char numlock_table[10] = {
 178    KEY_INSERT, KEY_END,    KEY_DOWN,   KEY_PGDN,   KEY_LEFT,
 179    KEY_5_PAD,  KEY_RIGHT,  KEY_HOME,   KEY_UP,     KEY_PGUP
 180 };
 181
 182
 183 /* kb_wait_for_write_ready:
 184  *  Wait for the keyboard controller to set the ready-for-write bit.
 185  */
 186 static __inline int
 187 kb_wait_for_write_ready (void)
 188 {
 189    int timeout = 4096;
 190
 191    while ((timeout > 0) && (inportb(0x64) & 2)) timeout--;
 192
 193    return (timeout > 0);
 194 }
 195
 196
 197 /* kb_wait_for_read_ready:
 198  *  Wait for the keyboard controller to set the ready-for-read bit.
 199  */
 200 static __inline int
 201 kb_wait_for_read_ready (void)
 202 {
 203    int timeout = 16384;
 204
 205    while ((timeout > 0) && (!(inportb(0x64) & 1))) timeout--;
 206
 207    return (timeout > 0);
 208 }
 209
 210
 211 /* kb_send_data:
 212  *  Sends a byte to the keyboard controller. Returns 1 if all OK.
 213  */
 214 static __inline int
 215 kb_send_data (unsigned char data)
 216 {
 217    int resends = 4;
 218    int timeout, temp;
 219
 220    do {
 221       if (!kb_wait_for_write_ready())
 222          return 0;
 223
 224       outportb(0x60, data);
 225       timeout = 4096;
 226
 227       while (--timeout > 0) {
 228          if (!kb_wait_for_read_ready())
 229             return 0;
 230
 231          temp = inportb(0x60);
 232
 233          if (temp == 0xFA)
 234             return 1;
 235
 236          if (temp == 0xFE)
 237             break;
 238       }
 239    } while ((resends-- > 0) && (timeout > 0));
 240
 241    return 0;
 242 }
 243
 244
 245 static void
 246 update_leds (int leds)
 247 {
 248    if (leds_ok) {
 249       if (!in_a_terrupt)
 250          DISABLE();
 251
 252       if (!kb_send_data(0xED)) {
 253          kb_send_data(0xF4);
 254          leds_ok = FALSE;
 255       } else if (!kb_send_data((leds >> 8) & 7)) {
 256          kb_send_data(0xF4);
 257          leds_ok = FALSE;
 258       }
 259
 260       if (!in_a_terrupt)
 261          ENABLE();
 262    }
 263 } ENDOFUNC(update_leds)
 264
 265
 266 static void
 267 inject_key (int scancode)
 268 {
 269    unsigned short *table;
 270
 271    if ((scancode >= KEY_0_PAD) && (scancode <= KEY_9_PAD)) {
 272       if (((key_shifts & KB_NUMLOCK_FLAG) != 0) == ((key_shifts & KB_SHIFT_FLAG) != 0)) {
 273          scancode = numlock_table[scancode - KEY_0_PAD];
 274       }
 275       table = standard_key_ascii_table;
 276    } else if (key_shifts & KB_CTRL_FLAG) {
 277       table = standard_key_control_table;
 278    } else if (key_shifts & KB_SHIFT_FLAG) {
 279       if (key_shifts & KB_CAPSLOCK_FLAG) {
 280          if (standard_key_ascii_table[scancode] == standard_key_capslock_table[scancode]) {
 281             table = standard_key_shift_table;
 282          } else {
 283             table = standard_key_ascii_table;
 284          }
 285       } else {
 286          table = standard_key_shift_table;
 287       }
 288    } else if (key_shifts & KB_CAPSLOCK_FLAG) {
 289       table = standard_key_capslock_table;
 290    } else {
 291       table = standard_key_ascii_table;
 292    }
 293
 294    key_buffer.key[key_buffer.end++] = (scancode << 16) | table[scancode];
 295
 296    if (key_buffer.end >= KEY_BUFFER_SIZE)
 297       key_buffer.end = 0;
 298    if (key_buffer.end == key_buffer.start) {
 299       key_buffer.start++;
 300       if (key_buffer.start >= KEY_BUFFER_SIZE)
 301          key_buffer.start = 0;
 302    }
 303 } ENDOFUNC(inject_key)
 304
 305
 306 static void
 307 handle_code (int scancode, int keycode)
 308 {
 309    in_a_terrupt++;
 310
 311    if (keycode == 0) {            /* pause */
 312       inject_key(scancode);
 313       pc_key[KEY_PAUSE] ^= TRUE;
 314    } else if (scancode) {
 315       int flag;
 316
 317       if (scancode >= KEY_MODIFIERS) {
 318          flag = modifier_table[scancode - KEY_MODIFIERS];
 319       } else {
 320          flag = 0;
 321       }
 322       if ((char)keycode < 0) {    /* release */
 323          pc_key[scancode] = FALSE;
 324          if (flag & KB_MODIFIERS) {
 325             key_shifts &= ~flag;
 326          }
 327       } else {                    /* keypress */
 328          pc_key[scancode] = TRUE;
 329          if (flag & KB_MODIFIERS) {
 330             key_shifts |= flag;
 331          }
 332          if (flag & KB_LED_FLAGS) {
 333             key_shifts ^= flag;
 334             update_leds(key_shifts);
 335          }
 336          if (scancode < KEY_MODIFIERS) {
 337             inject_key(scancode);
 338          }
 339       }
 340    }
 341
 342    in_a_terrupt--;
 343 } ENDOFUNC(handle_code)
 344
 345
 346 static int
 347 keyboard ()
 348 {
 349    unsigned char temp, scancode;
 350
 351    temp = inportb(0x60);
 352
 353    if (temp <= 0xe1) {
 354       if (key_pause_loop) {
 355          if (!--key_pause_loop) handle_code(KEY_PAUSE, 0);
 356       } else
 357          switch (temp) {
 358             case 0xe0:
 359                key_enhanced = TRUE;
 360                break;
 361             case 0xe1:
 362                key_pause_loop = 5;
 363                break;
 364             default:
 365                if (key_enhanced) {
 366                   key_enhanced = FALSE;
 367                   scancode = hw_to_mycode_ex[temp & 0x7f];
 368                } else {
 369                   scancode = hw_to_mycode[temp & 0x7f];
 370                }
 371                handle_code(scancode, temp);
 372          }
 373    }
 374
 375    if (((temp==0x4F)||(temp==0x53))&&(key_shifts&KB_CTRL_FLAG)&&(key_shifts&KB_ALT_FLAG)) {
 376       /* Hack alert:
 377        * only SIGINT (but not Ctrl-Break)
 378        * calls the destructors and will safely clean up
 379        */
 380        __asm("\n\
 381                 movb    $0x79, %%al             \n\
 382                 call    ___djgpp_hw_exception   \n\
 383        ":::"%eax", "%ebx", "%ecx", "%edx", "%esi", "%edi", "memory");
 384    }
 385
 386    __asm("\n\
 387                 inb     $0x61, %%al     \n\
 388                 movb    %%al, %%ah      \n\
 389                 orb     $0x80, %%al     \n\
 390                 outb    %%al, $0x61     \n\
 391                 xchgb   %%al, %%ah      \n\
 392                 outb    %%al, $0x61     \n\
 393                 movb    $0x20, %%al     \n\
 394                 outb    %%al, $0x20     \n\
 395    ":::"%eax");
 396    return 0;
 397 } ENDOFUNC(keyboard)
 398
 399
 400 int
 401 pc_keypressed (void)
 402 {
 403    return (key_buffer.start!=key_buffer.end);
 404 }
 405
 406
 407 int
 408 pc_readkey (void)
 409 {
 410    if (keyboard_installed) {
 411       int key;
 412
 413       while (key_buffer.start == key_buffer.end) {
 414          __dpmi_yield();
 415       }
 416
 417       DISABLE();
 418       key = key_buffer.key[key_buffer.start++];
 419       if (key_buffer.start >= KEY_BUFFER_SIZE)
 420          key_buffer.start = 0;
 421       ENABLE();
 422
 423       return key;
 424    } else {
 425       return 0;
 426    }
 427 }
 428
 429
 430 int
 431 pc_keydown (int code)
 432 {
 433    return pc_key[code];
 434 }
 435
 436
 437 int
 438 pc_keyshifts (void)
 439 {
 440    return key_shifts;
 441 }
 442
 443
 444 void
 445 pc_remove_keyb (void)
 446 {
 447    if (keyboard_installed) {
 448       int s1, s2, s3;
 449
 450       keyboard_installed = FALSE;
 451       pc_clexit(pc_remove_keyb);
 452
 453       DISABLE();
 454       _farsetsel(__djgpp_dos_sel);
 455       _farnspokew(0x41c, _farnspeekw(0x41a));
 456
 457       s1 = _farnspeekb(0x417) & 0x80;
 458       s2 = _farnspeekb(0x418) & 0xFC;
 459       s3 = _farnspeekb(0x496) & 0xF3;
 460
 461       if (pc_key[KEY_RSHIFT])   { s1 |= 1; }
 462       if (pc_key[KEY_LSHIFT])   { s1 |= 2; }
 463       if (pc_key[KEY_LCONTROL]) { s2 |= 1; s1 |= 4; }
 464       if (pc_key[KEY_ALT])      { s1 |= 8; s2 |= 2; }
 465       if (pc_key[KEY_RCONTROL]) { s1 |= 4; s3 |= 4; }
 466       if (pc_key[KEY_ALTGR])    { s1 |= 8; s3 |= 8; }
 467
 468       if (key_shifts & KB_SCROLOCK_FLAG) s1 |= 16;
 469       if (key_shifts & KB_NUMLOCK_FLAG)  s1 |= 32;
 470       if (key_shifts & KB_CAPSLOCK_FLAG) s1 |= 64;
 471
 472       _farnspokeb(0x417, s1);
 473       _farnspokeb(0x418, s2);
 474       _farnspokeb(0x496, s3);
 475       update_leds(key_shifts);
 476
 477       ENABLE();
 478       pc_remove_irq(KEYB_IRQ);
 479    }
 480 }
 481
 482
 483 int
 484 pc_install_keyb (void)
 485 {
 486    if (keyboard_installed || pc_install_irq(KEYB_IRQ, keyboard)) {
 487       return -1;
 488    } else {
 489       int s1, s2, s3;
 490
 491       LOCKDATA(key_buffer);
 492       LOCKDATA(key_enhanced);
 493       LOCKDATA(key_pause_loop);
 494       LOCKDATA(key_shifts);
 495       LOCKDATA(leds_ok);
 496       LOCKDATA(in_a_terrupt);
 497       LOCKDATA(pc_key);
 498       LOCKDATA(modifier_table);
 499       LOCKDATA(hw_to_mycode);
 500       LOCKDATA(hw_to_mycode_ex);
 501       LOCKDATA(standard_key_ascii_table);
 502       LOCKDATA(standard_key_capslock_table);
 503       LOCKDATA(standard_key_shift_table);
 504       LOCKDATA(standard_key_control_table);
 505       LOCKDATA(numlock_table);
 506       LOCKFUNC(update_leds);
 507       LOCKFUNC(inject_key);
 508       LOCKFUNC(handle_code);
 509       LOCKFUNC(keyboard);
 510
 511       DISABLE();
 512       _farsetsel(__djgpp_dos_sel);
 513       _farnspokew(0x41c, _farnspeekw(0x41a));
 514
 515       key_shifts = 0;
 516       s1 = _farnspeekb(0x417);
 517       s2 = _farnspeekb(0x418);
 518       s3 = _farnspeekb(0x496);
 519
 520       if (s1 & 1) { key_shifts |= KB_SHIFT_FLAG; pc_key[KEY_RSHIFT]   = TRUE; }
 521       if (s1 & 2) { key_shifts |= KB_SHIFT_FLAG; pc_key[KEY_LSHIFT]   = TRUE; }
 522       if (s2 & 1) { key_shifts |= KB_CTRL_FLAG;  pc_key[KEY_LCONTROL] = TRUE; }
 523       if (s2 & 2) { key_shifts |= KB_ALT_FLAG;   pc_key[KEY_ALT]      = TRUE; }
 524       if (s3 & 4) { key_shifts |= KB_CTRL_FLAG;  pc_key[KEY_RCONTROL] = TRUE; }
 525       if (s3 & 8) { key_shifts |= KB_ALT_FLAG;   pc_key[KEY_ALTGR]    = TRUE; }
 526
 527       if (s1 & 16) key_shifts |= KB_SCROLOCK_FLAG;
 528       if (s1 & 32) key_shifts |= KB_NUMLOCK_FLAG;
 529       if (s1 & 64) key_shifts |= KB_CAPSLOCK_FLAG;
 530       update_leds(key_shifts);
 531
 532       key_enhanced = key_pause_loop = 0;
 533       key_buffer.start = key_buffer.end = 0;
 534       ENABLE();
 535
 536       pc_atexit(pc_remove_keyb);
 537       keyboard_installed = TRUE;
 538       return 0;
 539    }
 540 }