VirtualBox

source: vbox/trunk/src/VBox/Devices/Graphics/BIOS/vgarom.asm

Last change on this file was 93828, checked in by vboxsync, 2 years ago

VGABIOS: Set DS correctly before calling into C POST code.

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1;; ============================================================================================
2;;
3;; Copyright (C) 2001,2002 the LGPL VGABios developers Team
4;;
5;; This library is free software; you can redistribute it and/or
6;; modify it under the terms of the GNU Lesser General Public
7;; License as published by the Free Software Foundation; either
8;; version 2 of the License, or (at your option) any later version.
9;;
10;; This library is distributed in the hope that it will be useful,
11;; but WITHOUT ANY WARRANTY; without even the implied warranty of
12;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13;; Lesser General Public License for more details.
14;;
15;; You should have received a copy of the GNU Lesser General Public
16;; License along with this library; if not, write to the Free Software
17;; Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18;;
19;; ============================================================================================
20;;
21;; This VGA Bios is specific to the plex86/bochs Emulated VGA card.
22;; You can NOT drive any physical vga card with it.
23;;
24;; ============================================================================================
25;;
26
27
28; Oracle LGPL Disclaimer: For the avoidance of doubt, except that if any license choice
29; other than GPL or LGPL is available it will apply instead, Oracle elects to use only
30; the Lesser General Public License version 2.1 (LGPLv2) at this time for any software where
31; a choice of LGPL license versions is made available with the language indicating
32; that LGPLv2 or any later version may be used, or where a choice of which version
33; of the LGPL is applied is otherwise unspecified.
34
35include vgadefs.inc
36include commondefs.inc
37
38public vgabios_int10_handler
39
40VGAROM segment public 'CODE'
41
42; Implemented in C
43extrn _int10_func:near
44extrn _vgabios_init_func:near
45
46ifdef VBE
47; Implemented in separate assembly module
48extrn vbe_biosfn_return_current_mode:near
49extrn vbe_biosfn_display_window_control:near
50extrn vbe_biosfn_set_get_display_start:near
51extrn vbe_biosfn_set_get_dac_palette_format:near
52extrn vbe_biosfn_set_get_palette_data:near
53extrn vbe_biosfn_return_protected_mode_interface:near
54endif
55
56ifdef VGA_DEBUG
57extrn _int10_debugmsg:near
58extrn _printf:near
59extrn _unimplemented:near
60extrn _unknown:near
61endif
62
63vgabios_start:
64
65db 055h, 0AAh ; ROM signature, required for expansion ROMs
66db 40h ; ROM module length in units of 512 bytes */
67
68
69vgabios_entry_point:
70
71 jmp vgabios_init
72
73 org 1Eh
74
75 db 'IBM',0
76
77vgabios_init:
78;; We have to set ds to access the right data segment
79 push cs
80 pop ds
81 cld
82 jmp _vgabios_init_func
83
84;;
85;; int10 handled here
86;;
87
88SET_DEFAULT_CPU_286
89
90vgabios_int10_handler:
91 pushf
92ifdef VGA_DEBUG
93 push es
94 push ds
95 DO_pusha
96 push cs
97 pop ds
98 cld
99 call _int10_debugmsg
100 DO_popa
101 pop ds
102 pop es
103endif
104 cmp ah, 0Fh
105 jne int10_test_1A
106 call biosfn_get_video_mode
107 jmp int10_end
108int10_test_1A:
109 cmp ah, 1Ah
110 jne int10_test_0B
111 call biosfn_group_1A
112 jmp int10_end
113int10_test_0B:
114 cmp ah, 0Bh
115 jne int10_test_1103
116 call biosfn_group_0B
117 jmp int10_end
118int10_test_1103:
119 cmp ax, 1103h
120 jne int10_test_12
121 call biosfn_set_text_block_specifier
122 jmp int10_end
123int10_test_12:
124 cmp ah, 12h
125 jne int10_test_101B
126 cmp bl, 10h
127 jne int10_test_BL30
128 call biosfn_get_ega_info
129 jmp int10_end
130int10_test_BL30:
131 cmp bl, 30h
132 jne int10_test_BL31
133 call biosfn_select_vert_res
134 jmp int10_end
135int10_test_BL31:
136 cmp bl, 31h
137 jne int10_test_BL32
138 call biosfn_enable_default_palette_loading
139 jmp int10_end
140int10_test_BL32:
141 cmp bl, 32h
142 jne int10_test_BL33
143 call biosfn_enable_video_addressing
144 jmp int10_end
145int10_test_BL33:
146 cmp bl, 33h
147 jne int10_test_BL34
148 call biosfn_enable_grayscale_summing
149 jmp int10_end
150int10_test_BL34:
151 cmp bl, 34h
152 jne int10_normal
153 call biosfn_enable_cursor_emulation
154 jmp int10_end
155int10_test_101B:
156 cmp ax, 101Bh
157 je int10_normal
158 cmp ah, 10h
159ifndef VBE
160 jne int10_normal
161else
162 jne int10_test_4F
163endif
164 call biosfn_group_10
165 jmp int10_end
166ifdef VBE
167int10_test_4F:
168 cmp ah, 4Fh
169 jne int10_normal
170 cmp al, 3
171 jne int10_test_vbe_05
172 call vbe_biosfn_return_current_mode
173 jmp int10_end
174int10_test_vbe_05:
175 cmp al, 5
176 jne int10_test_vbe_07
177 call vbe_biosfn_display_window_control
178 jmp int10_end
179int10_test_vbe_07:
180 cmp al, 7
181 jne int10_test_vbe_08
182 call vbe_biosfn_set_get_display_start
183 jmp int10_end
184int10_test_vbe_08:
185 cmp al, 8
186 jne int10_test_vbe_09
187 call vbe_biosfn_set_get_dac_palette_format
188 jmp int10_end
189int10_test_vbe_09:
190 cmp al, 9
191 jne int10_test_vbe_0A
192 call vbe_biosfn_set_get_palette_data
193 jmp int10_end
194int10_test_vbe_0A:
195 cmp al, 0Ah
196 jne int10_normal
197 call vbe_biosfn_return_protected_mode_interface
198 jmp int10_end
199endif
200
201int10_normal:
202 push es
203 push ds
204 DO_pusha
205
206;; We have to set ds to access the right data segment
207 push cs
208 pop ds
209 cld
210 call _int10_func
211
212 DO_popa
213 pop ds
214 pop es
215int10_end:
216 popf
217 iret
218
219;;--------------------------------------------------------------------------------------------
220
221biosfn_group_0B:
222 cmp bh, 0
223 je biosfn_set_border_color
224 cmp bh, 1
225 je biosfn_set_palette
226ifdef VGA_DEBUG
227 call _unknown
228endif
229 ret
230biosfn_set_border_color:
231 push ax
232 push bx
233 push cx
234 push dx
235 push ds
236 mov dx, BIOSMEM_SEG
237 mov ds, dx
238 mov dx, VGAREG_ACTL_RESET
239 in al, dx
240 cmp byte ptr ds:[BIOSMEM_CURRENT_MODE], 3
241 jbe set_border_done
242 mov dx, VGAREG_ACTL_ADDRESS
243 mov al, 00h
244 out dx, al
245 mov al, bl
246 and al, 0Fh
247 test al, 08h
248 jz set_low_border
249 add al, 08h
250set_low_border:
251 out dx, al
252 mov cl, 1
253 and bl, 10h
254set_intensity_loop:
255 mov dx, VGAREG_ACTL_ADDRESS
256 mov al, cl
257 out dx, al
258 mov dx, VGAREG_ACTL_READ_DATA
259 in al, dx
260 and al, 0EFh
261 or al, bl
262 mov dx, VGAREG_ACTL_ADDRESS
263 out dx, al
264 inc cl
265 cmp cl, 4
266 jne set_intensity_loop
267set_border_done:
268 mov al, 20h
269 out dx, al
270ifdef VBOX
271 mov dx, VGAREG_ACTL_RESET
272 in al, dx
273endif ; VBOX
274 pop ds
275 pop dx
276 pop cx
277 pop bx
278 pop ax
279 ret
280biosfn_set_palette:
281 push ax
282 push bx
283 push cx
284 push dx
285 mov dx, VGAREG_ACTL_RESET
286 in al, dx
287 mov cl, 01
288 and bl, 01
289set_cga_palette_loop:
290 mov dx, VGAREG_ACTL_ADDRESS
291 mov al, cl
292 out dx, al
293 mov dx, VGAREG_ACTL_READ_DATA
294 in al, dx
295 and al, 0FEh
296 or al, bl
297 mov dx, VGAREG_ACTL_ADDRESS
298 out dx, al
299 inc cl
300 cmp cl, 4
301 jne set_cga_palette_loop
302 mov al, 20h
303 out dx, al
304ifdef VBOX
305 mov dx, VGAREG_ACTL_RESET
306 in al, dx
307endif ; VBOX
308 pop dx
309 pop cx
310 pop bx
311 pop ax
312 ret
313
314;;--------------------------------------------------------------------------------------------
315
316biosfn_get_video_mode:
317 push ds
318 mov ax, BIOSMEM_SEG
319 mov ds, ax
320 push bx
321 mov bx, BIOSMEM_CURRENT_PAGE
322 mov al, [bx]
323 pop bx
324 mov bh, al
325 push bx
326 mov bx, BIOSMEM_VIDEO_CTL
327 mov ah, [bx]
328 and ah, 80h
329 mov bx, BIOSMEM_CURRENT_MODE
330 mov al, [bx]
331 or al, ah
332 mov bx, BIOSMEM_NB_COLS
333 mov ah, [bx]
334 pop bx
335 pop ds
336 ret
337
338;--------------------------------------------------------------------------------------------
339
340biosfn_group_10:
341 cmp al, 0
342 jne int10_test_1001
343 jmp biosfn_set_single_palette_reg
344int10_test_1001:
345 cmp al, 1
346 jne int10_test_1002
347 jmp biosfn_set_overscan_border_color
348int10_test_1002:
349 cmp al, 2
350 jne int10_test_1003
351 jmp biosfn_set_all_palette_reg
352int10_test_1003:
353 cmp al, 3
354 jne int10_test_1007
355 jmp biosfn_toggle_intensity
356int10_test_1007:
357 cmp al, 7
358 jne int10_test_1008
359 jmp biosfn_get_single_palette_reg
360int10_test_1008:
361 cmp al, 8
362 jne int10_test_1009
363 jmp biosfn_read_overscan_border_color
364int10_test_1009:
365 cmp al, 9
366 jne int10_test_1010
367 jmp biosfn_get_all_palette_reg
368int10_test_1010:
369 cmp al, 10h
370 jne int10_test_1012
371 jmp biosfn_set_single_dac_reg
372int10_test_1012:
373 cmp al, 12h
374 jne int10_test_1013
375 jmp biosfn_set_all_dac_reg
376int10_test_1013:
377 cmp al, 13h
378 jne int10_test_1015
379 jmp biosfn_select_video_dac_color_page
380int10_test_1015:
381 cmp al, 15h
382 jne int10_test_1017
383 jmp biosfn_read_single_dac_reg
384int10_test_1017:
385 cmp al, 17h
386 jne int10_test_1018
387 jmp biosfn_read_all_dac_reg
388int10_test_1018:
389 cmp al, 18h
390 jne int10_test_1019
391 jmp biosfn_set_pel_mask
392int10_test_1019:
393 cmp al, 19h
394 jne int10_test_101A
395 jmp biosfn_read_pel_mask
396int10_test_101A:
397 cmp al, 1Ah
398 jne int10_group_10_unknown
399 jmp biosfn_read_video_dac_state
400int10_group_10_unknown:
401ifdef VGA_DEBUG
402 call _unknown
403endif
404 ret
405
406biosfn_set_single_palette_reg:
407 cmp bl, 14h
408 ja no_actl_reg1
409 push ax
410 push dx
411 mov dx, VGAREG_ACTL_RESET
412 in al, dx
413 mov dx, VGAREG_ACTL_ADDRESS
414 mov al, bl
415 out dx, al
416 mov al, bh
417 out dx, al
418 mov al, 20h
419 out dx, al
420ifdef VBOX
421 mov dx, VGAREG_ACTL_RESET
422 in al, dx
423endif ; VBOX
424 pop dx
425 pop ax
426no_actl_reg1:
427 ret
428
429;--------------------------------------------------------------------------------------------
430
431biosfn_set_overscan_border_color:
432 push bx
433 mov bl, 11h
434 call biosfn_set_single_palette_reg
435 pop bx
436 ret
437
438;--------------------------------------------------------------------------------------------
439
440biosfn_set_all_palette_reg:
441 push ax
442 push bx
443 push cx
444 push dx
445 mov bx, dx
446 mov dx, VGAREG_ACTL_RESET
447 in al, dx
448 mov cl, 0
449 mov dx, VGAREG_ACTL_ADDRESS
450set_palette_loop:
451 mov al, cl
452 out dx, al
453 mov al, es:[bx]
454 out dx, al
455 inc bx
456 inc cl
457 cmp cl, 10h
458 jne set_palette_loop
459 mov al, 11h
460 out dx, al
461 mov al, es:[bx]
462 out dx, al
463 mov al, 20h
464 out dx, al
465ifdef VBOX
466 mov dx, VGAREG_ACTL_RESET
467 in al, dx
468endif ; VBOX
469 pop dx
470 pop cx
471 pop bx
472 pop ax
473 ret
474
475;;--------------------------------------------------------------------------------------------
476
477biosfn_toggle_intensity:
478 push ax
479 push bx
480 push dx
481 mov dx, VGAREG_ACTL_RESET
482 in al, dx
483 mov dx, VGAREG_ACTL_ADDRESS
484 mov al, 10h
485 out dx, al
486 mov dx, VGAREG_ACTL_READ_DATA
487 in al, dx
488 and al, 0F7h
489 and bl, 01
490if VBOX_BIOS_CPU gt 8086
491 shl bl, 3
492else
493 shl bl, 1
494 shl bl, 1
495 shl bl, 1
496endif
497 or al, bl
498 mov dx, VGAREG_ACTL_ADDRESS
499 out dx, al
500 mov al, 20h
501 out dx, al
502ifdef VBOX
503 mov dx, VGAREG_ACTL_RESET
504 in al, dx
505endif ; VBOX
506 pop dx
507 pop bx
508 pop ax
509 ret
510
511;;--------------------------------------------------------------------------------------------
512
513biosfn_get_single_palette_reg:
514 cmp bl, 14h
515 ja no_actl_reg2
516 push ax
517 push dx
518 mov dx, VGAREG_ACTL_RESET
519 in al, dx
520 mov dx, VGAREG_ACTL_ADDRESS
521 mov al, bl
522 out dx, al
523 mov dx, VGAREG_ACTL_READ_DATA
524 in al, dx
525 mov bh, al
526 mov dx, VGAREG_ACTL_RESET
527 in al, dx
528 mov dx, VGAREG_ACTL_ADDRESS
529 mov al, 20h
530 out dx, al
531ifdef VBOX
532 mov dx, VGAREG_ACTL_RESET
533 in al, dx
534endif ; VBOX
535 pop dx
536 pop ax
537no_actl_reg2:
538 ret
539
540;;--------------------------------------------------------------------------------------------
541
542biosfn_read_overscan_border_color:
543 push ax
544 push bx
545 mov bl, 11h
546 call biosfn_get_single_palette_reg
547 mov al, bh
548 pop bx
549 mov bh, al
550 pop ax
551 ret
552
553;;--------------------------------------------------------------------------------------------
554
555biosfn_get_all_palette_reg:
556 push ax
557 push bx
558 push cx
559 push dx
560 mov bx, dx
561 mov cl, 0
562get_palette_loop:
563 mov dx, VGAREG_ACTL_RESET
564 in al, dx
565 mov dx, VGAREG_ACTL_ADDRESS
566 mov al, cl
567 out dx, al
568 mov dx, VGAREG_ACTL_READ_DATA
569 in al, dx
570 mov es:[bx], al
571 inc bx
572 inc cl
573 cmp cl, 10h
574 jne get_palette_loop
575 mov dx, VGAREG_ACTL_RESET
576 in al, dx
577 mov dx, VGAREG_ACTL_ADDRESS
578 mov al, 11h
579 out dx, al
580 mov dx, VGAREG_ACTL_READ_DATA
581 in al, dx
582 mov es:[bx], al
583 mov dx, VGAREG_ACTL_RESET
584 in al, dx
585 mov dx, VGAREG_ACTL_ADDRESS
586 mov al, 20h
587 out dx, al
588ifdef VBOX
589 mov dx, VGAREG_ACTL_RESET
590 in al, dx
591endif ; VBOX
592 pop dx
593 pop cx
594 pop bx
595 pop ax
596 ret
597
598;;--------------------------------------------------------------------------------------------
599
600biosfn_set_single_dac_reg:
601 push ax
602 push dx
603 mov dx, VGAREG_DAC_WRITE_ADDRESS
604 mov al, bl
605 out dx, al
606 mov dx, VGAREG_DAC_DATA
607 pop ax
608 push ax
609 mov al, ah
610 out dx, al
611 mov al, ch
612 out dx, al
613 mov al, cl
614 out dx, al
615 pop dx
616 pop ax
617 ret
618
619;;--------------------------------------------------------------------------------------------
620
621biosfn_set_all_dac_reg:
622 push ax
623 push bx
624 push cx
625 push dx
626 mov dx, VGAREG_DAC_WRITE_ADDRESS
627 mov al, bl
628 out dx, al
629 pop dx
630 push dx
631 mov bx, dx
632 mov dx, VGAREG_DAC_DATA
633set_dac_loop:
634 mov al, es:[bx]
635 out dx, al
636 inc bx
637 mov al, es:[bx]
638 out dx, al
639 inc bx
640 mov al, es:[bx]
641 out dx, al
642 inc bx
643 dec cx
644 jnz set_dac_loop
645 pop dx
646 pop cx
647 pop bx
648 pop ax
649 ret
650
651;;--------------------------------------------------------------------------------------------
652
653biosfn_select_video_dac_color_page:
654 push ax
655 push bx
656 push dx
657 mov dx, VGAREG_ACTL_RESET
658 in al, dx
659 mov dx, VGAREG_ACTL_ADDRESS
660 mov al, 10h
661 out dx, al
662 mov dx, VGAREG_ACTL_READ_DATA
663 in al, dx
664 and bl, 01
665 jnz set_dac_page
666 and al, 07Fh
667if VBOX_BIOS_CPU gt 8086
668 shl bh, 7
669else
670 shl bh, 1
671 shl bh, 1
672 shl bh, 1
673 shl bh, 1
674 shl bh, 1
675 shl bh, 1
676 shl bh, 1
677endif
678 or al, bh
679 mov dx, VGAREG_ACTL_ADDRESS
680 out dx, al
681 jmp set_actl_normal
682set_dac_page:
683 push ax
684 mov dx, VGAREG_ACTL_RESET
685 in al, dx
686 mov dx, VGAREG_ACTL_ADDRESS
687 mov al, 14h
688 out dx, al
689 pop ax
690 and al, 80h
691 jnz set_dac_16_page
692if VBOX_BIOS_CPU gt 8086
693 shl bh, 2
694else
695 shl bh, 1
696 shl bh, 1
697endif
698set_dac_16_page:
699 and bh, 0Fh
700 mov al, bh
701 out dx, al
702set_actl_normal:
703 mov al, 20h
704 out dx, al
705ifdef VBOX
706 mov dx, VGAREG_ACTL_RESET
707 in al, dx
708endif ; VBOX
709 pop dx
710 pop bx
711 pop ax
712 ret
713
714;;--------------------------------------------------------------------------------------------
715
716biosfn_read_single_dac_reg:
717 push ax
718 push dx
719 mov dx, VGAREG_DAC_READ_ADDRESS
720 mov al, bl
721 out dx, al
722 pop ax
723 mov ah, al
724 mov dx, VGAREG_DAC_DATA
725 in al, dx
726 xchg al, ah
727 push ax
728 in al, dx
729 mov ch, al
730 in al, dx
731 mov cl, al
732 pop dx
733 pop ax
734 ret
735
736;;--------------------------------------------------------------------------------------------
737
738biosfn_read_all_dac_reg:
739 push ax
740 push bx
741 push cx
742 push dx
743 mov dx, VGAREG_DAC_READ_ADDRESS
744 mov al, bl
745 out dx, al
746 pop dx
747 push dx
748 mov bx, dx
749 mov dx, VGAREG_DAC_DATA
750read_dac_loop:
751 in al, dx
752 mov es:[bx], al
753 inc bx
754 in al, dx
755 mov es:[bx], al
756 inc bx
757 in al, dx
758 mov es:[bx], al
759 inc bx
760 dec cx
761 jnz read_dac_loop
762 pop dx
763 pop cx
764 pop bx
765 pop ax
766 ret
767
768;;--------------------------------------------------------------------------------------------
769
770biosfn_set_pel_mask:
771 push ax
772 push dx
773 mov dx, VGAREG_PEL_MASK
774 mov al, bl
775 out dx, al
776 pop dx
777 pop ax
778 ret
779
780;;--------------------------------------------------------------------------------------------
781
782biosfn_read_pel_mask:
783 push ax
784 push dx
785 mov dx, VGAREG_PEL_MASK
786 in al, dx
787 mov bl, al
788 pop dx
789 pop ax
790 ret
791
792;;--------------------------------------------------------------------------------------------
793
794biosfn_read_video_dac_state:
795 push ax
796 push dx
797 mov dx, VGAREG_ACTL_RESET
798 in al, dx
799 mov dx, VGAREG_ACTL_ADDRESS
800 mov al, 10h
801 out dx, al
802 mov dx, VGAREG_ACTL_READ_DATA
803 in al, dx
804 mov bl, al
805if VBOX_BIOS_CPU gt 8086
806 shr bl, 7
807else
808 shr bl, 1
809 shr bl, 1
810 shr bl, 1
811 shr bl, 1
812 shr bl, 1
813 shr bl, 1
814 shr bl, 1
815endif
816 mov dx, VGAREG_ACTL_RESET
817 in al, dx
818 mov dx, VGAREG_ACTL_ADDRESS
819 mov al, 14h
820 out dx, al
821 mov dx, VGAREG_ACTL_READ_DATA
822 in al, dx
823 mov bh, al
824 and bh, 0Fh
825 test bl, 01
826 jnz get_dac_16_page
827if VBOX_BIOS_CPU gt 8086
828 shr bh, 2
829else
830 shr bh, 1
831 shr bh, 1
832endif
833get_dac_16_page:
834 mov dx, VGAREG_ACTL_RESET
835 in al, dx
836 mov dx, VGAREG_ACTL_ADDRESS
837 mov al, 20h
838 out dx, al
839ifdef VBOX
840 mov dx, VGAREG_ACTL_RESET
841 in al, dx
842endif ; VBOX
843 pop dx
844 pop ax
845 ret
846
847;;--------------------------------------------------------------------------------------------
848
849biosfn_set_text_block_specifier:
850 push ax
851 push dx
852 mov dx, VGAREG_SEQU_ADDRESS
853 mov ah, bl
854 mov al, 03
855 out dx, ax
856 pop dx
857 pop ax
858 ret
859
860;;--------------------------------------------------------------------------------------------
861
862biosfn_get_ega_info:
863 push ds
864 push ax
865 mov ax, BIOSMEM_SEG
866 mov ds, ax
867 xor ch, ch
868 mov bx, BIOSMEM_SWITCHES
869 mov cl, [bx]
870 and cl, 0Fh
871 mov bx, BIOSMEM_CRTC_ADDRESS
872 mov ax, [bx]
873 mov bx, 0003h
874 cmp ax, VGAREG_MDA_CRTC_ADDRESS
875 jne mode_ega_color
876 mov bh, 01
877mode_ega_color:
878 pop ax
879 pop ds
880 ret
881
882;;--------------------------------------------------------------------------------------------
883
884biosfn_select_vert_res:
885
886; res : 00 200 lines, 01 350 lines, 02 400 lines
887
888 push ds
889 push bx
890 push dx
891 mov dl, al
892 mov ax, BIOSMEM_SEG
893 mov ds, ax
894 mov bx, BIOSMEM_MODESET_CTL
895 mov al, [bx]
896 mov bx, BIOSMEM_SWITCHES
897 mov ah, [bx]
898 cmp dl, 1
899 je vert_res_350
900 jb vert_res_200
901 cmp dl, 2
902 je vert_res_400
903ifdef VGA_DEBUG
904 mov al, dl
905 xor ah, ah
906 push ax
907 mov bx, msg_vert_res
908 push bx
909 call _printf
910 add sp, 4
911endif
912 jmp set_retcode
913vert_res_400:
914
915 ; reset modeset ctl bit 7 and set bit 4
916 ; set switches bit 3-0 to 09
917
918 and al, 07Fh
919 or al, 010h
920 and ah, 0F0h
921 or ah, 009h
922 jnz set_vert_res
923vert_res_350:
924
925 ; reset modeset ctl bit 7 and bit 4
926 ; set switches bit 3-0 to 09
927
928 and al, 06Fh
929 and ah, 0F0h
930 or ah, 009h
931 jnz set_vert_res
932vert_res_200:
933
934 ; set modeset ctl bit 7 and reset bit 4
935 ; set switches bit 3-0 to 08
936
937 and al, 0EFh
938 or al, 080h
939 and ah, 0F0h
940 or ah, 008h
941set_vert_res:
942 mov bx, BIOSMEM_MODESET_CTL
943 mov [bx], al
944 mov bx, BIOSMEM_SWITCHES
945 mov [bx], ah
946set_retcode:
947 mov ax, 1212h
948 pop dx
949 pop bx
950 pop ds
951 ret
952
953ifdef VGA_DEBUG
954msg_vert_res:
955db "Select vert res (%02x) was discarded", 13, 10, 0
956endif
957
958
959biosfn_enable_default_palette_loading:
960 push ds
961 push bx
962 push dx
963 mov dl, al
964 and dl, 01
965if VBOX_BIOS_CPU gt 8086
966 shl dl, 3
967else
968 shl dl, 1
969 shl dl, 1
970 shl dl, 1
971endif
972 mov ax, BIOSMEM_SEG
973 mov ds, ax
974 mov bx, BIOSMEM_MODESET_CTL
975 mov al, [bx]
976 and al, 0F7h
977 or al, dl
978 mov [bx], al
979 mov ax, 1212h
980 pop dx
981 pop bx
982 pop ds
983 ret
984
985
986biosfn_enable_video_addressing:
987 push bx
988 push dx
989 mov bl, al
990 and bl, 01
991 xor bl, 01
992 shl bl, 1
993 mov dx, VGAREG_READ_MISC_OUTPUT
994 in al, dx
995 and al, 0FDh
996 or al, bl
997 mov dx, VGAREG_WRITE_MISC_OUTPUT
998 out dx, al
999 mov ax, 1212h
1000 pop dx
1001 pop bx
1002 ret
1003
1004
1005biosfn_enable_grayscale_summing:
1006 push ds
1007 push bx
1008 push dx
1009 mov dl, al
1010 and dl, 01h
1011 xor dl, 01h
1012 shl dl, 1
1013 mov ax, BIOSMEM_SEG
1014 mov ds, ax
1015 mov bx, BIOSMEM_MODESET_CTL
1016 mov al, [bx]
1017 and al, 0FDh
1018 or al, dl
1019 mov [bx], al
1020 mov ax, 1212h
1021 pop dx
1022 pop bx
1023 pop ds
1024 ret
1025
1026
1027biosfn_enable_cursor_emulation:
1028 push ds
1029 push bx
1030 push dx
1031 mov dl, al
1032 and dl, 01
1033 xor dl, 01
1034 mov ax, BIOSMEM_SEG
1035 mov ds, ax
1036 mov bx, BIOSMEM_MODESET_CTL
1037 mov al, [bx]
1038 and al, 0FEh
1039 or al, dl
1040 mov [bx], al
1041 mov ax, 1212h
1042 pop dx
1043 pop bx
1044 pop ds
1045 ret
1046
1047;;--------------------------------------------------------------------------------------------
1048
1049biosfn_group_1A:
1050 cmp al, 0
1051 je biosfn_read_display_code
1052 cmp al, 1
1053 je biosfn_set_display_code
1054ifdef VGA_DEBUG
1055 call _unknown
1056endif
1057 ret
1058biosfn_read_display_code:
1059 push ds
1060 push ax
1061 mov ax, BIOSMEM_SEG
1062 mov ds, ax
1063 mov bx, BIOSMEM_DCC_INDEX
1064 mov al, [bx]
1065 mov bl, al
1066 xor bh, bh
1067 pop ax
1068 mov al, ah
1069 pop ds
1070 ret
1071biosfn_set_display_code:
1072 push ds
1073 push ax
1074 push bx
1075 mov ax, BIOSMEM_SEG
1076 mov ds, ax
1077 mov ax, bx
1078 mov bx, BIOSMEM_DCC_INDEX
1079 mov [bx], al
1080ifdef VGA_DEBUG
1081 mov al, ah
1082 xor ah, ah
1083 push ax
1084 mov bx, msg_alt_dcc
1085 push bx
1086 call _printf
1087 add sp, 4
1088endif
1089 pop bx
1090 pop ax
1091 mov al, ah
1092 pop ds
1093 ret
1094
1095ifdef VGA_DEBUG
1096msg_alt_dcc:
1097db "Alternate Display code (%02x) was discarded", 13, 10, 0
1098endif
1099
1100VGAROM ends
1101
1102 end
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