VirtualBox

source: vbox/trunk/src/VBox/Devices/Graphics/BIOS/vberom.asm@ 93956

Last change on this file since 93956 was 83002, checked in by vboxsync, 5 years ago

VGABIOS: Further reduced mode set stack usage, centralized cld invocation, reduced explicit C000 segment usage.
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File size: 19.6 KB
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1;; ============================================================================================
2;;
3;; Copyright (C) 2002 Jeroen Janssen
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 VBE is part of the VGA Bios specific to the plex86/bochs Emulated VGA card.
22;; You can NOT drive any physical vga card with it.
23;;
24;; ============================================================================================
25;;
26;; This VBE Bios is based on information taken from :
27;; - VESA BIOS EXTENSION (VBE) Core Functions Standard Version 3.0 located at www.vesa.org
28;;
29;; ============================================================================================
30
31
32; Oracle LGPL Disclaimer: For the avoidance of doubt, except that if any license choice
33; other than GPL or LGPL is available it will apply instead, Oracle elects to use only
34; the Lesser General Public License version 2.1 (LGPLv2) at this time for any software where
35; a choice of LGPL license versions is made available with the language indicating
36; that LGPLv2 or any later version may be used, or where a choice of which version
37; of the LGPL is applied is otherwise unspecified.
38
39include vgadefs.inc
40include commondefs.inc
41
42public _vga_compat_setup
43public dispi_set_enable_
44public dispi_set_bank_
45public _dispi_set_bank_farcall
46public _dispi_get_max_bpp
47public _vbe_has_vbe_display
48
49public vbe_biosfn_return_current_mode
50public vbe_biosfn_display_window_control
51public vbe_biosfn_set_get_display_start
52public vbe_biosfn_set_get_dac_palette_format
53public vbe_biosfn_set_get_palette_data
54public vbe_biosfn_return_protected_mode_interface
55
56VGAROM segment public 'CODE'
57
58SET_DEFAULT_CPU
59
60VBE_BYTEWISE_IO EQU 1
61
62;; Bytewise in/out
63ifdef VBE_BYTEWISE_IO
64
65public do_out_dx_ax
66public do_in_ax_dx
67
68do_out_dx_ax:
69 xchg ah, al
70 out dx, al
71 xchg ah, al
72 out dx, al
73 ret
74
75do_in_ax_dx:
76 in al, dx
77 xchg ah, al
78 in al, dx
79 ret
80
81 out_dx_ax EQU call do_out_dx_ax
82 in_ax_dx EQU call do_in_ax_dx
83else
84 out_dx_ax EQU out dx, ax
85 in_ax_dx EQU in ax, dx
86endif
87
88;; Vertical retrace waiting
89wait_vsync:
90 push ax
91 push dx
92 mov dx, 03DAh ; @todo use a symbolic constant!
93wv_loop:
94 in al, dx
95 test al, 8
96 jz wv_loop
97 pop dx
98 pop ax
99 ret
100
101wait_not_vsync:
102 push ax
103 push dx
104 mov dx, 03DAh ; @todo use a symbolic constant!
105wnv_loop:
106 in al, dx
107 test al, 8
108 jnz wnv_loop
109 pop dx
110 pop ax
111 ret
112
113
114; AL = bits per pixel / AH = bytes per pixel
115dispi_get_bpp:
116 push dx
117 mov dx, VBE_DISPI_IOPORT_INDEX
118 mov ax, VBE_DISPI_INDEX_BPP
119 out_dx_ax
120 mov dx, VBE_DISPI_IOPORT_DATA
121 in_ax_dx
122 cmp al, 4
123 jbe get_bpp_noinc
124 mov ah, al
125if VBOX_BIOS_CPU gt 8086
126 shr ah, 3
127else
128 shr ah, 1
129 shr ah, 1
130 shr ah, 1
131endif
132 test al, 07
133 jz get_bpp_noinc
134 inc ah
135get_bpp_noinc:
136 pop dx
137 ret
138
139; get display capabilities
140
141_dispi_get_max_bpp:
142 push dx
143 push bx
144 call dispi_get_enable
145 mov bx, ax
146 or ax, VBE_DISPI_GETCAPS
147 call dispi_set_enable_
148 mov dx, VBE_DISPI_IOPORT_INDEX
149 mov ax, VBE_DISPI_INDEX_BPP
150 out_dx_ax
151 mov dx, VBE_DISPI_IOPORT_DATA
152 in_ax_dx
153 push ax
154 mov ax, bx
155 call dispi_set_enable_
156 pop ax
157 pop bx
158 pop dx
159 ret
160
161dispi_set_enable_:
162 push dx
163 push ax
164 mov dx, VBE_DISPI_IOPORT_INDEX
165 mov ax, VBE_DISPI_INDEX_ENABLE
166 out_dx_ax
167 pop ax
168 mov dx, VBE_DISPI_IOPORT_DATA
169 out_dx_ax
170 pop dx
171 ret
172
173dispi_get_enable:
174 push dx
175 mov dx, VBE_DISPI_IOPORT_INDEX
176 mov ax, VBE_DISPI_INDEX_ENABLE
177 out_dx_ax
178 mov dx, VBE_DISPI_IOPORT_DATA
179 in_ax_dx
180 pop dx
181 ret
182
183dispi_set_bank_:
184 push dx
185 push ax
186 mov dx, VBE_DISPI_IOPORT_INDEX
187 mov ax, VBE_DISPI_INDEX_BANK
188 out_dx_ax
189 pop ax
190 mov dx, VBE_DISPI_IOPORT_DATA
191 out_dx_ax
192 pop dx
193 ret
194
195dispi_get_bank:
196 push dx
197 mov dx, VBE_DISPI_IOPORT_INDEX
198 mov ax, VBE_DISPI_INDEX_BANK
199 out_dx_ax
200 mov dx, VBE_DISPI_IOPORT_DATA
201 in_ax_dx
202 pop dx
203 ret
204
205_dispi_set_bank_farcall:
206 cmp bx, 0100h
207 je dispi_set_bank_farcall_get
208 or bx,bx
209 jnz dispi_set_bank_farcall_error
210 mov ax, dx
211 push dx
212 push ax
213 mov ax, VBE_DISPI_INDEX_BANK
214 mov dx, VBE_DISPI_IOPORT_INDEX
215 out_dx_ax
216 pop ax
217 mov dx, VBE_DISPI_IOPORT_DATA
218 out_dx_ax
219 in_ax_dx
220 pop dx
221 cmp dx,ax
222 jne dispi_set_bank_farcall_error
223 mov ax, 004Fh
224 retf
225dispi_set_bank_farcall_get:
226 mov ax, VBE_DISPI_INDEX_BANK
227 mov dx, VBE_DISPI_IOPORT_INDEX
228 out_dx_ax
229 mov dx, VBE_DISPI_IOPORT_DATA
230 in_ax_dx
231 mov dx,ax
232 retf
233dispi_set_bank_farcall_error:
234 mov ax, 014Fh
235 retf
236
237dispi_set_x_offset:
238 push dx
239 push ax
240 mov dx, VBE_DISPI_IOPORT_INDEX
241 mov ax, VBE_DISPI_INDEX_X_OFFSET
242 out_dx_ax
243 pop ax
244 mov dx, VBE_DISPI_IOPORT_DATA
245 out_dx_ax
246 pop dx
247 ret
248
249dispi_get_x_offset:
250 push dx
251 mov dx, VBE_DISPI_IOPORT_INDEX
252 mov ax, VBE_DISPI_INDEX_X_OFFSET
253 out_dx_ax
254 mov dx, VBE_DISPI_IOPORT_DATA
255 in_ax_dx
256 pop dx
257 ret
258
259dispi_set_y_offset:
260 push dx
261 push ax
262 mov dx, VBE_DISPI_IOPORT_INDEX
263 mov ax, VBE_DISPI_INDEX_Y_OFFSET
264 out_dx_ax
265 pop ax
266 mov dx, VBE_DISPI_IOPORT_DATA
267 out_dx_ax
268 pop dx
269 ret
270
271dispi_get_y_offset:
272 push dx
273 mov dx, VBE_DISPI_IOPORT_INDEX
274 mov ax, VBE_DISPI_INDEX_Y_OFFSET
275 out_dx_ax
276 mov dx, VBE_DISPI_IOPORT_DATA
277 in_ax_dx
278 pop dx
279 ret
280
281vga_set_virt_width:
282 push ax
283 push bx
284 push dx
285 mov bx, ax
286 call dispi_get_bpp
287 cmp al, 4
288 ja set_width_svga
289 shr bx, 1
290set_width_svga:
291if VBOX_BIOS_CPU gt 8086
292 shr bx, 3
293else
294 shr bx, 1
295 shr bx, 1
296 shr bx, 1
297endif
298 mov dx, VGAREG_VGA_CRTC_ADDRESS
299 mov ah, bl
300 mov al, 13h
301 out dx, ax
302 pop dx
303 pop bx
304 pop ax
305 ret
306
307_vga_compat_setup:
308 push ax
309 push dx
310
311 ; set CRT X resolution
312 mov dx, VBE_DISPI_IOPORT_INDEX
313 mov ax, VBE_DISPI_INDEX_XRES
314 out_dx_ax
315 mov dx, VBE_DISPI_IOPORT_DATA
316 in_ax_dx
317 push ax
318 mov dx, VGAREG_VGA_CRTC_ADDRESS
319 mov ax, 0011h
320 out dx, ax
321 pop ax
322 push ax
323if VBOX_BIOS_CPU gt 8086
324 shr ax, 3
325else
326 shr ax, 1
327 shr ax, 1
328 shr ax, 1
329endif
330 dec ax
331 mov ah, al
332 mov al, 01
333 out dx, ax
334 pop ax
335 call vga_set_virt_width
336
337 ; set CRT Y resolution
338 mov dx, VBE_DISPI_IOPORT_INDEX
339 mov ax, VBE_DISPI_INDEX_YRES
340 out_dx_ax
341 mov dx, VBE_DISPI_IOPORT_DATA
342 in_ax_dx
343 dec ax
344 push ax
345 mov dx, VGAREG_VGA_CRTC_ADDRESS
346 mov ah, al
347 mov al, 12h
348 out dx, ax
349 pop ax
350 mov al, 07
351 out dx, al
352 inc dx
353 in al, dx
354 and al, 0BDh
355 test ah, 01
356 jz bit8_clear
357 or al, 02
358bit8_clear:
359 test ah, 02
360 jz bit9_clear
361 or al, 40h
362bit9_clear:
363 out dx, al
364
365 ; other settings
366 mov dx, VGAREG_VGA_CRTC_ADDRESS
367 mov ax, 0009
368 out dx, al
369 mov dx, VGAREG_VGA_CRTC_DATA
370 in al, dx
371 and al, 60h ; clear double scan bit and cell height
372 out dx, al
373 mov dx, VGAREG_VGA_CRTC_ADDRESS
374 mov al, 17h
375 out dx, al
376 mov dx, VGAREG_VGA_CRTC_DATA
377 in al, dx
378 or al, 03
379 out dx, al
380 mov dx, VGAREG_ACTL_RESET
381 in al, dx
382 mov dx, VGAREG_ACTL_ADDRESS
383 mov al, 10h
384 out dx, al
385 mov dx, VGAREG_ACTL_READ_DATA
386 in al, dx
387 or al, 01
388 mov dx, VGAREG_ACTL_ADDRESS
389 out dx, al
390 mov al, 20h
391 out dx, al
392 mov dx, VGAREG_GRDC_ADDRESS
393 mov ax, 0506h
394 out dx, ax
395 mov dx, VGAREG_SEQU_ADDRESS
396 mov ax, 0F02h
397 out dx, ax
398
399 ; settings for >= 8bpp
400 mov dx, VBE_DISPI_IOPORT_INDEX
401 mov ax, VBE_DISPI_INDEX_BPP
402 out_dx_ax
403 mov dx, VBE_DISPI_IOPORT_DATA
404 in_ax_dx
405 cmp al, 08
406 jb vga_compat_end
407 mov dx, VGAREG_VGA_CRTC_ADDRESS
408 mov al, 14h
409 out dx, al
410 mov dx, VGAREG_VGA_CRTC_DATA
411 in al, dx
412 or al, 40h
413 out dx, al
414 mov dx, VGAREG_ACTL_RESET
415 in al, dx
416 mov dx, VGAREG_ACTL_ADDRESS
417 mov al, 10h
418 out dx, al
419 mov dx, VGAREG_ACTL_READ_DATA
420 in al, dx
421 or al, 40h
422 mov dx, VGAREG_ACTL_ADDRESS
423 out dx, al
424 mov al, 20h
425 out dx, al
426 mov dx, VGAREG_SEQU_ADDRESS
427 mov al, 04
428 out dx, al
429 mov dx, VGAREG_SEQU_DATA
430 in al, dx
431 or al, 08
432 out dx, al
433 mov dx, VGAREG_GRDC_ADDRESS
434 mov al, 05
435 out dx, al
436 mov dx, VGAREG_GRDC_DATA
437 in al, dx
438 and al, 9Fh
439 or al, 40h
440 out dx, al
441
442vga_compat_end:
443 pop dx
444 pop ax
445
446
447; Has VBE display - Returns true if VBE display detected
448
449_vbe_has_vbe_display:
450 push ds
451 push bx
452 mov ax, BIOSMEM_SEG
453 mov ds, ax
454 mov bx, BIOSMEM_VBE_FLAG
455 mov al, [bx]
456 and al, 01
457 xor ah, ah
458 pop bx
459 pop ds
460 ret
461
462
463; Function 03h - Return Current VBE Mode
464;
465; Input:
466; AX = 4F03h
467; Output:
468; AX = VBE Return Status
469; BX = Current VBE Mode
470;
471;
472vbe_biosfn_return_current_mode:
473 push ds
474 mov ax, BIOSMEM_SEG
475 mov ds, ax
476 call dispi_get_enable
477 and ax, VBE_DISPI_ENABLED
478 jz no_vbe_mode
479 mov bx, BIOSMEM_VBE_MODE
480 mov ax, [bx]
481 mov bx, ax
482 jnz vbe_03_ok
483no_vbe_mode:
484 mov bx, BIOSMEM_CURRENT_MODE
485 mov al, [bx]
486 mov bl, al
487 xor bh, bh
488vbe_03_ok:
489 mov ax, 004Fh
490 pop ds
491 ret
492
493
494; Function 05h - Display Window Control
495;
496; Input:
497; AX = 4F05h
498; (16-bit) BH = 00h Set memory window
499; = 01h Get memory window
500; BL = Window number
501; = 00h Window A
502; = 01h Window B
503; DX = Window number in video memory in window
504; granularity units (Set Memory Window only)
505; Note:
506; If this function is called while in a linear frame buffer mode,
507; this function must fail with completion code AH=03h
508;
509; Output:
510; AX = VBE Return Status
511; DX = Window number in window granularity units
512; (Get Memory Window only)
513
514vbe_biosfn_display_window_control:
515 cmp bl, 0
516 jne vbe_05_failed
517 cmp bh, 1
518 je get_display_window
519 jb set_display_window
520 mov ax, 0100h
521 ret
522set_display_window:
523 mov ax, dx
524 call dispi_set_bank_
525 call dispi_get_bank
526 cmp ax, dx
527 jne vbe_05_failed
528 mov ax, 004Fh
529 ret
530get_display_window:
531 call dispi_get_bank
532 mov dx, ax
533 mov ax, 004Fh
534 ret
535vbe_05_failed:
536 mov ax, 014Fh
537 ret
538
539
540; Function 07h - Set/Get Display Start
541;
542; Input(16-bit):
543; AX = 4F07h
544; BH = 00h Reserved and must be 00h
545; BL = 00h Set Display Start
546; = 01h Get Display Start
547; = 02h Schedule Display Start (Alternate)
548; = 03h Schedule Stereoscopic Display Start
549; = 04h Get Scheduled Display Start Status
550; = 05h Enable Stereoscopic Mode
551; = 06h Disable Stereoscopic Mode
552; = 80h Set Display Start during Vertical Retrace
553; = 82h Set Display Start during Vertical Retrace (Alternate)
554; = 83h Set Stereoscopic Display Start during Vertical Retrace
555; ECX = If BL=02h/82h Display Start Address in bytes
556; If BL=03h/83h Left Image Start Address in bytes
557; EDX = If BL=03h/83h Right Image Start Address in bytes
558; CX = If BL=00h/80h First Displayed Pixel In Scan Line
559; DX = If BL=00h/80h First Displayed Scan Line
560;
561; Output:
562; AX = VBE Return Status
563; BH = If BL=01h Reserved and will be 0
564; CX = If BL=01h First Displayed Pixel In Scan Line
565; If BL=04h 0 if flip has not occurred, not 0 if it has
566; DX = If BL=01h First Displayed Scan Line
567;
568; Input(32-bit):
569; BH = 00h Reserved and must be 00h
570; BL = 00h Set Display Start
571; = 80h Set Display Start during Vertical Retrace
572; CX = Bits 0-15 of display start address
573; DX = Bits 16-31 of display start address
574; ES = Selector for memory mapped registers
575;
576vbe_biosfn_set_get_display_start:
577 cmp bl, 80h
578 je set_display_start_wait
579 cmp bl, 1
580 je get_display_start
581 jb set_display_start
582 mov ax, 0100h
583 ret
584set_display_start_wait:
585 call wait_not_vsync
586 call wait_vsync
587set_display_start:
588 mov ax, cx
589 call dispi_set_x_offset
590 mov ax, dx
591 call dispi_set_y_offset
592 mov ax, 004Fh
593 ret
594get_display_start:
595 call dispi_get_x_offset
596 mov cx, ax
597 call dispi_get_y_offset
598 mov dx, ax
599 xor bh, bh
600 mov ax, 004Fh
601 ret
602
603
604; Function 08h - Set/Get Dac Palette Format
605;
606; Input:
607; AX = 4F08h
608; BL = 00h set DAC palette width
609; = 01h get DAC palette width
610; BH = If BL=00h: desired number of bits per primary color
611; Output:
612; AX = VBE Return Status
613; BH = current number of bits per primary color (06h = standard VGA)
614;
615vbe_biosfn_set_get_dac_palette_format:
616 cmp bl, 1
617 je get_dac_palette_format
618 jb set_dac_palette_format
619 mov ax, 0100h
620 ret
621set_dac_palette_format:
622 call dispi_get_enable
623 cmp bh, 6
624 je set_normal_dac
625 cmp bh, 8
626 jne vbe_08_unsupported
627 or ax, VBE_DISPI_8BIT_DAC
628 jnz set_dac_mode
629set_normal_dac:
630 and ax, NOT VBE_DISPI_8BIT_DAC
631set_dac_mode:
632 call dispi_set_enable_
633get_dac_palette_format:
634 mov bh, 6
635 call dispi_get_enable
636 and ax, VBE_DISPI_8BIT_DAC
637 jz vbe_08_ok
638 mov bh, 8
639vbe_08_ok:
640 mov ax, 004Fh
641 ret
642vbe_08_unsupported:
643 mov ax, 014Fh
644 ret
645
646
647; Function 09h - Set/Get Palette Data
648;
649; Input:
650; AX = 4F09h
651; (16-bit) BL = 00h Set palette data
652; = 01h Get palette data
653; = 02h Set secondary palette data
654; = 03h Get secondary palette data
655; = 80h Set palette data during VRetrace
656; CX = Number of entries to update (<= 256)
657; DX = First entry to update
658; ES:DI = Table of palette values
659; Output:
660; AX = VBE Return Status
661;
662; Notes:
663; Secondary palette support is a "future extension".
664; Attempts to set/get it should return status 02h.
665;
666; In VBE 3.0, reading palette data is optional and
667; subfunctions 01h and 03h may return failure.
668;
669; The format of palette entries is as follows:
670;
671; PaletteEntry struc
672; Blue db ? ; Blue channel value (6 or 8 bits)
673; Green db ? ; Green channel value (6 or 8 bits)
674; Red db ? ; Red channel value (6 or 8 bits)
675; Padding db ? ; DWORD alignment byte (unused)
676; PaletteEntry ends
677;
678; Most applications use VGA DAC registers directly to
679; set/get palette in VBE modes. However, subfn 4F09h is
680; required for NonVGA controllers (eg. XGA).
681;
682vbe_biosfn_set_get_palette_data:
683 test bl, bl
684 jz set_palette_data
685 cmp bl, 01
686 je get_palette_data
687 cmp bl, 03
688 jbe vbe_09_nohw
689 cmp bl, 80h
690 jne vbe_09_unsupported
691if 0
692 ; this is where we could wait for vertical retrace
693endif
694set_palette_data:
695 DO_pushad
696 push ds
697 push es
698 pop ds
699 mov al, dl
700 mov dx, VGAREG_DAC_WRITE_ADDRESS
701 out dx, al
702 inc dx
703 mov si, di
704set_pal_loop:
705if VBOX_BIOS_CPU ge 80386
706 lodsd
707 ror eax, 16
708 out dx, al
709 rol eax, 8
710 out dx, al
711 rol eax, 8
712 out dx, al
713else
714 lodsw
715 mov bx, ax
716 lodsw
717 out dx, al
718 mov al, bh
719 out dx, al
720 mov al, bl
721 out dx, al
722endif
723 loop set_pal_loop
724 pop ds
725 DO_popad
726vbe_09_ok:
727 mov ax, 004Fh
728 ret
729
730get_palette_data:
731 DO_pushad
732 mov al, dl
733 mov dx, VGAREG_DAC_READ_ADDRESS
734 out dx, al
735 add dl, 2
736if VBOX_BIOS_CPU ge 80386
737get_pal_loop:
738 xor eax, eax
739 in al, dx
740 shl eax, 8
741 in al, dx
742 shl eax, 8
743 in al, dx
744 stosd
745else
746 xor bx, bx
747get_pal_loop:
748 in al, dx
749 mov bl, al
750 in al, dx
751 mov ah, al
752 in al, dx
753 stosw
754 mov ax, bx
755 stosw
756endif
757 loop get_pal_loop
758 DO_popad
759 jmp vbe_09_ok
760
761vbe_09_unsupported:
762 mov ax, 014Fh
763 ret
764vbe_09_nohw:
765 mov ax, 024Fh
766 ret
767
768
769; Function 0Ah - Return VBE Protected Mode Interface
770;
771; Input: AX = 4F0Ah VBE 2.0 Protected Mode Interface
772; BL = 00h Return protected mode table
773; Output: AX = Status
774; ES = Real Mode Segment of Table
775; DI = Offset of Table
776; CX = Length of Table including protected mode code
777; (for copying purposes)
778;
779vbe_biosfn_return_protected_mode_interface:
780 test bl, bl
781 jnz _fail
782 push cs
783 pop es
784 mov di, offset vesa_pm_start
785 mov cx, vesa_pm_end - vesa_pm_start
786 mov ax, 004Fh
787 ret
788_fail:
789 mov ax, 014fh
790 ret
791
792VGAROM ends
793
794;;
795;; 32-bit VBE interface
796;;
797
798.386
799
800public vesa_pm_start
801public vesa_pm_end
802
803VBE32 segment public use32 'CODE'
804
805 align 2
806
807vesa_pm_start:
808 dw vesa_pm_set_window - vesa_pm_start
809 dw vesa_pm_set_display_start - vesa_pm_start
810 dw vesa_pm_unimplemented - vesa_pm_start
811 dw vesa_pm_io_ports_table - vesa_pm_start
812vesa_pm_io_ports_table:
813 dw VBE_DISPI_IOPORT_INDEX
814 dw VBE_DISPI_IOPORT_INDEX + 1
815 dw VBE_DISPI_IOPORT_DATA
816 dw VBE_DISPI_IOPORT_DATA + 1
817 dw 3B6h
818 dw 3B7h
819 dw 0FFFFh
820 dw 0FFFFh
821
822vesa_pm_set_window:
823 cmp bx, 0
824 je vesa_pm_set_display_window1
825 mov ax, 0100h
826 ret
827vesa_pm_set_display_window1:
828 mov ax, dx
829 push dx
830 push ax
831 mov dx, VBE_DISPI_IOPORT_INDEX
832 mov ax, VBE_DISPI_INDEX_BANK
833 out dx, ax
834 pop ax
835 mov dx, VBE_DISPI_IOPORT_DATA
836 out dx, ax
837 in ax, dx
838 pop dx
839 cmp dx, ax
840 jne illegal_window
841 mov ax, 004Fh
842 ret
843illegal_window:
844 mov ax, 014Fh
845 ret
846vesa_pm_set_display_start:
847 cmp bl, 80h
848 je vesa_pm_set_display_start1_wait
849 cmp bl, 00
850 je vesa_pm_set_display_start1
851 mov ax, 0100h
852 ret
853vesa_pm_set_display_start1_wait:
854 push edx
855 mov dx, 03DAh ; @todo: use symbolic constant
856wnv_loop_32:
857 in al, dx
858 test al, 8
859 jnz wnv_loop_32
860wv_loop_32:
861 in al, dx
862 test al, 8
863 jz wv_loop_32
864 pop edx
865vesa_pm_set_display_start1:
866; convert offset to (X, Y) coordinate
867; (would be simpler to change Bochs VBE API...)
868 push eax
869 push ecx
870 push edx
871 push esi
872 push edi
873 shl edx, 16
874 and ecx, 0FFFFh
875 or ecx, edx
876 shl ecx, 2
877 mov eax, ecx
878 push eax
879 mov dx, VBE_DISPI_IOPORT_INDEX
880 mov ax, VBE_DISPI_INDEX_VIRT_WIDTH
881 out dx, ax
882 mov dx, VBE_DISPI_IOPORT_DATA
883 in ax, dx
884 movzx ecx, ax
885 mov dx, VBE_DISPI_IOPORT_INDEX
886 mov ax, VBE_DISPI_INDEX_BPP
887 out dx, ax
888 mov dx, VBE_DISPI_IOPORT_DATA
889 in ax, dx
890 movzx esi, ax
891 pop eax
892
893 cmp esi, 4
894 jz bpp4_mode
895 add esi, 7
896 shr esi, 3
897 imul ecx, esi
898 xor edx, edx
899 div ecx
900 mov edi, eax
901 mov eax, edx
902 xor edx, edx
903 div esi
904 jmp set_xy_regs
905
906bpp4_mode:
907 shr ecx, 1
908 xor edx, edx
909 div ecx
910 mov edi, eax
911 mov eax, edx
912 shl eax, 1
913
914set_xy_regs:
915 push dx
916 push ax
917 mov dx, VBE_DISPI_IOPORT_INDEX
918 mov ax, VBE_DISPI_INDEX_X_OFFSET
919 out dx, ax
920 pop ax
921 mov dx, VBE_DISPI_IOPORT_DATA
922 out dx, ax
923 pop dx
924
925 mov ax, di
926 push dx
927 push ax
928 mov dx, VBE_DISPI_IOPORT_INDEX
929 mov ax, VBE_DISPI_INDEX_Y_OFFSET
930 out dx, ax
931 pop ax
932 mov dx, VBE_DISPI_IOPORT_DATA
933 out dx, ax
934 pop dx
935
936 pop edi
937 pop esi
938 pop edx
939 pop ecx
940 pop eax
941 mov ax, 004fh
942 ret
943
944vesa_pm_unimplemented:
945 mov ax, 014Fh
946 ret
947vesa_pm_end:
948
949VBE32 ends
950
951 end
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