kernel/krl_incs/text.inc

   1 ;----------------------------------------------------------;
   2 ; BOS kernel                Christoffer Bubach, 2003-2005. ;
   3 ;----------------------------------------------------------;
   4 ;                                                          ;
   5 ;    Textmode screen functions.                            ;
   6 ;                                                          ;
   7 ;----------------------------------------------------------;
   8
   9 ;-----------------;
  10 ;   variables     ;
  11 ;-----------------;
  12      screen_rows     db   25                          ; all comments assume
  13      screen_cols     db   80                          ; that this is 25 & 80
  14      cursor_pos      dw   0
  15
  16
  17 ;--------------------------------------;
  18 ;  change cursor attribs               ;
  19 ;            in: bx = cursor attribs   ;
  20 ;--------------------------------------;
  21 changecursor:
  22           push    ax
  23           push    dx
  24
  25           mov     dx, 0x3D4
  26           mov     al, 0x0A
  27           mov     ah, bh
  28           out     dx, ax
  29           inc     ax
  30           mov     ah, bl
  31           out     dx, ax
  32
  33           pop     dx
  34           pop     ax
  35           ret
  36
  37
  38 ;----------------------;
  39 ;  clear the screen    ;
  40 ;----------------------;
  41 cls:
  42           push    bx
  43           push    cx
  44
  45           movzx   cx, [screen_rows]
  46      .loop:
  47           call    _scroll_up
  48           loop    .loop
  49
  50           mov     bx, 0
  51           call    setcursor
  52
  53           pop     cx
  54           pop     bx
  55           ret
  56
  57
  58 ;-----------------------------------;
  59 ;  get the cursor pos               ;
  60 ;            out: bh = x   bl = y   ;
  61 ;-----------------------------------;
  62 getcursorxy:
  63           push    ax
  64
  65           call    getcursor
  66           mov     ax, bx
  67           mov     bl, [screen_cols]
  68           div     bl
  69           mov     bl, al
  70           mov     bh, ah
  71
  72           pop     ax
  73           ret
  74
  75
  76 ;-------------------------------;
  77 ;  get the cursor pos           ;
  78 ;            out: bx = offset   ;
  79 ;-------------------------------;
  80 getcursor:
  81           push    ax
  82           push    dx
  83
  84           mov     dx, 0x3D4
  85           mov     al, 0x0E
  86           out     dx, al
  87           inc     dx
  88           in      al, dx
  89           mov     bh, al
  90           mov     al, 0x0F
  91           dec     dx
  92           out     dx, al
  93           inc     dx
  94           in      al, dx
  95           mov     bl, al
  96
  97           pop     dx
  98           pop     ax
  99           ret
 100
 101
 102 ;------------------------------;
 103 ;  set the cursor to:          ;
 104 ;            bh = x   bl = y   ;
 105 ;------------------------------;
 106 setcursorxy:
 107           push    ax
 108           push    bx
 109
 110           xor     ax, ax
 111           mov     al, [screen_cols]
 112           mul     bl                                  ; bl * al = ax
 113           movzx   bx, bh
 114           add     bx, ax
 115           call    setcursor
 116
 117           pop     bx
 118           pop     ax
 119           ret
 120
 121
 122 ;--------------------------;
 123 ;  set the cursor to:      ;
 124 ;            bx = offset   ;
 125 ;--------------------------;
 126 setcursor:
 127           push    ax
 128           push    bx
 129           push    dx
 130
 131           mov     al, 0x0E
 132           mov     ah, bh
 133           mov     dx, 0x3D4
 134           out     dx, ax
 135           inc     ax
 136           mov     ah, bl
 137           out     dx, ax
 138
 139           pop     dx
 140           pop     bx
 141           pop     ax
 142           ret
 143
 144
 145 ;-----------------------;
 146 ;  cursor position +1   ;
 147 ;-----------------------;
 148 inccursor:
 149           push    ax
 150           push    bx
 151
 152           mov     al, [screen_cols]
 153           mov     bl, [screen_rows]
 154           mul     bl
 155           dec     ax
 156
 157           call    getcursor
 158           cmp     bx, ax                              ; 0x7CF = (80*25)-1
 159           jne     .cont
 160           call    scroll_up
 161           jmp     .end
 162
 163      .cont:
 164           inc     bx
 165           call    setcursor
 166
 167      .end:
 168           pop     bx
 169           pop     ax
 170           ret
 171
 172
 173 ;-----------------------;
 174 ;  cursor position -1   ;
 175 ;-----------------------;
 176 deccursor:
 177           push    bx
 178
 179           call    getcursor
 180           cmp     bx, 0
 181           je      .end
 182
 183           dec     bx
 184           call    setcursor
 185
 186      .end:
 187           pop     bx
 188           ret
 189
 190
 191
 192 ;---------------------------------------;
 193 ;  backspace - delete last typed char   ;
 194 ;---------------------------------------;
 195 backspace:
 196           push    bx
 197
 198           call    getcursor
 199           cmp     bx, 0
 200           je      .end
 201
 202           call    deccursor
 203
 204           mov     bh, 0x07
 205           mov     bl, 0
 206           call    print_char
 207
 208           call    deccursor
 209
 210      .end:
 211           pop     bx
 212           ret
 213
 214
 215
 216 ;-----------------------------------------;
 217 ;  print char                             ;
 218 ;            in: bl = char, bh = attrib   ;
 219 ;-----------------------------------------;
 220 print_char:
 221           push    eax
 222           push    bx
 223
 224           cmp     bl, 13
 225           jne     .cont
 226           call    new_line
 227           jmp     .done
 228
 229      .cont:
 230           cmp     bl, 10                              ; ignore
 231           je      .done
 232
 233           push    bx
 234           call    getcursor
 235           movzx   eax, bx
 236           pop     bx
 237
 238           mov     [es:(eax*2 + 0xB8000)], bx
 239
 240           call    inccursor
 241      .done:
 242           pop     bx
 243           pop     eax
 244           ret
 245
 246
 247
 248 ;------------------------------------------;
 249 ;  print 32-bit hex value                  ;
 250 ;            in: ebx = value, cl = color   ;
 251 ;------------------------------------------;
 252 print_hex32:
 253           push    eax
 254           push    ebx
 255           push    ecx
 256           push    edx
 257
 258           mov     eax, ebx                            ; quick & dirty fix so
 259           mov     bh, cl                              ; input reg != eax
 260           mov     ecx, 8
 261
 262      .print_it:
 263           rol     eax, 4
 264           movzx   edx, al
 265           and     edx, 0x0F
 266           or      edx, 0x30
 267           cmp     edx, 0x39
 268           jna     .cont
 269           add     edx, 7
 270      .cont:
 271           mov     bl, dl
 272           call    print_char
 273           loop    .print_it
 274
 275           pop     edx
 276           pop     ecx
 277           pop     ebx
 278           pop     eax
 279           ret
 280
 281
 282
 283 ;-------------------------------------------------;
 284 ;  display a asciiz message on the screen         ;
 285 ;            in: esi = message, bl = color        ;
 286 ;-------------------------------------------------;
 287 print:
 288           push    eax
 289           push    bx
 290
 291           mov     ah, bl
 292           call    getcursor
 293           mov     [cursor_pos], bx
 294
 295      .displaychar:
 296           lodsb
 297           or      al, al
 298           jz      .done
 299
 300           cmp     al, 13
 301           jne     .cont
 302           mov     bx, [cursor_pos]
 303           call    setcursor
 304           call    new_line
 305           call    getcursor
 306           mov     [cursor_pos], bx
 307           jmp     .displaychar
 308
 309      .cont:
 310           cmp     al, 10                              ; ignore
 311           je      .displaychar
 312           movzx   ebx, [cursor_pos]
 313           mov     [es:(ebx*2 + 0xB8000)], ax
 314           inc     [cursor_pos]
 315           jmp     .displaychar
 316
 317      .done:
 318           mov     bx, [cursor_pos]
 319           call    setcursor                           ; update cursor on screen
 320
 321           pop     bx
 322           pop     eax
 323           ret
 324
 325
 326
 327 ;-----------------------------;
 328 ;  make a new line (CR, LF)   ;
 329 ;-----------------------------;
 330 new_line:
 331           push    bx
 332
 333           call    getcursorxy
 334           mov     bh, [screen_rows]
 335           dec     bh
 336           cmp     bl, bh                              ; 24
 337           jb      .newline
 338
 339           call    scroll_up
 340           jmp     .done
 341
 342      .newline:
 343           call    getcursorxy
 344           mov     bh, 0
 345           inc     bl
 346           call    setcursorxy
 347
 348      .done:
 349           pop     bx
 350           ret
 351
 352
 353
 354 ;----------------;
 355 ;  scrolling..   ;
 356 ;----------------;
 357 scroll_up:
 358           call    _scroll_up
 359
 360      .mv_curs:
 361           push    ax
 362           push    bx
 363
 364           xor     ax, ax
 365           mov     al, [screen_rows]                   ; mov bx, 80*24
 366           mov     bl, [screen_cols]
 367           dec     al
 368           mul     bl
 369           mov     bx, ax
 370           call    setcursor
 371
 372           pop     bx
 373           pop     ax
 374           ret
 375
 376      _scroll_up:
 377           push    eax
 378           push    ecx
 379           push    edi
 380           push    esi
 381
 382           mov     edi, 0xB8000
 383           movzx   esi, [screen_cols]
 384           shl     esi, 1                              ; 80*2 = 160
 385           mov     cl, [screen_rows]
 386           dec     cl
 387           mov     eax, esi
 388           mul     cl
 389           shr     ax, 2                               ; ax  = (160*24)/4
 390           movzx   ecx, ax                             ; ecx =   - || -
 391           add     esi, 0xB8000                        ; esi = 0xB8000+160
 392
 393           rep     movsd
 394
 395           mov     cl, [screen_cols]
 396           shl     cl, 1                               ; 80*2 = 160
 397           mov     al, [screen_rows]
 398           dec     al                                  ; al = 24
 399           mul     cl
 400           movzx   edi, ax
 401           add     edi, 0xB8000                        ; edi = 0xB8000+160*24
 402           movzx   ecx, [screen_cols]
 403           shr     ecx, 1                              ; 80/2
 404           mov     eax, 0x07000700                     ; fill with zeros
 405           rep     stosd
 406
 407           pop     esi
 408           pop     edi
 409           pop     ecx
 410           pop     eax
 411           ret