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Catacomb3D/ID_VW_A.ASM
Hans Kokx daaca5c6ef Initial commit
2026-03-12 19:22:23 +01:00

733 lines
25 KiB
NASM
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; Catacomb 3-D Source Code
; Copyright (C) 1993-2014 Flat Rock Software
;
; This program is free software; you can redistribute it and/or modify
; it under the terms of the GNU General Public License as published by
; the Free Software Foundation; either version 2 of the License, or
; (at your option) any later version.
;
; This program is distributed in the hope that it will be useful,
; but WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
; GNU General Public License for more details.
;
; You should have received a copy of the GNU General Public License along
; with this program; if not, write to the Free Software Foundation, Inc.,
; 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
; ID_VW_A.ASM
IDEAL
MODEL MEDIUM,C
INCLUDE "ID_ASM.EQU"
WAITFORVBL = 1 ; setting to 0 causes setscreen and waitvbl
; to skip waiting for VBL (for timing things)
;============================================================================
DATASEG
EXTRN screenseg :WORD
EXTRN drawofs :WORD
EXTRN bufferofs :WORD
EXTRN displayofs :WORD
EXTRN drawofs :WORD
EXTRN panadjust :WORD
EXTRN ylookup :WORD
EXTRN linewidth :WORD
EXTRN grsegs :WORD
EXTRN updateptr :WORD
EXTRN blockstarts :WORD ;offsets from drawofs for each update block
EXTRN fontspace :WORD
EXTRN fontnumber :WORD
planemask db ?
planenum db ?
screendest dw ?
linedelta dw ?
LABEL shiftdata0 WORD
dw 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13
dw 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27
dw 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41
dw 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55
dw 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69
dw 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83
dw 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97
dw 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111
dw 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125
dw 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139
dw 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153
dw 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167
dw 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181
dw 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195
dw 196, 197, 198, 199, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209
dw 210, 211, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 223
dw 224, 225, 226, 227, 228, 229, 230, 231, 232, 233, 234, 235, 236, 237
dw 238, 239, 240, 241, 242, 243, 244, 245, 246, 247, 248, 249, 250, 251
dw 252, 253, 254, 255
LABEL shiftdata1 WORD
dw 0,32768, 1,32769, 2,32770, 3,32771, 4,32772, 5,32773, 6,32774
dw 7,32775, 8,32776, 9,32777, 10,32778, 11,32779, 12,32780, 13,32781
dw 14,32782, 15,32783, 16,32784, 17,32785, 18,32786, 19,32787, 20,32788
dw 21,32789, 22,32790, 23,32791, 24,32792, 25,32793, 26,32794, 27,32795
dw 28,32796, 29,32797, 30,32798, 31,32799, 32,32800, 33,32801, 34,32802
dw 35,32803, 36,32804, 37,32805, 38,32806, 39,32807, 40,32808, 41,32809
dw 42,32810, 43,32811, 44,32812, 45,32813, 46,32814, 47,32815, 48,32816
dw 49,32817, 50,32818, 51,32819, 52,32820, 53,32821, 54,32822, 55,32823
dw 56,32824, 57,32825, 58,32826, 59,32827, 60,32828, 61,32829, 62,32830
dw 63,32831, 64,32832, 65,32833, 66,32834, 67,32835, 68,32836, 69,32837
dw 70,32838, 71,32839, 72,32840, 73,32841, 74,32842, 75,32843, 76,32844
dw 77,32845, 78,32846, 79,32847, 80,32848, 81,32849, 82,32850, 83,32851
dw 84,32852, 85,32853, 86,32854, 87,32855, 88,32856, 89,32857, 90,32858
dw 91,32859, 92,32860, 93,32861, 94,32862, 95,32863, 96,32864, 97,32865
dw 98,32866, 99,32867, 100,32868, 101,32869, 102,32870, 103,32871, 104,32872
dw 105,32873, 106,32874, 107,32875, 108,32876, 109,32877, 110,32878, 111,32879
dw 112,32880, 113,32881, 114,32882, 115,32883, 116,32884, 117,32885, 118,32886
dw 119,32887, 120,32888, 121,32889, 122,32890, 123,32891, 124,32892, 125,32893
dw 126,32894, 127,32895
LABEL shiftdata2 WORD
dw 0,16384,32768,49152, 1,16385,32769,49153, 2,16386,32770,49154, 3,16387
dw 32771,49155, 4,16388,32772,49156, 5,16389,32773,49157, 6,16390,32774,49158
dw 7,16391,32775,49159, 8,16392,32776,49160, 9,16393,32777,49161, 10,16394
dw 32778,49162, 11,16395,32779,49163, 12,16396,32780,49164, 13,16397,32781,49165
dw 14,16398,32782,49166, 15,16399,32783,49167, 16,16400,32784,49168, 17,16401
dw 32785,49169, 18,16402,32786,49170, 19,16403,32787,49171, 20,16404,32788,49172
dw 21,16405,32789,49173, 22,16406,32790,49174, 23,16407,32791,49175, 24,16408
dw 32792,49176, 25,16409,32793,49177, 26,16410,32794,49178, 27,16411,32795,49179
dw 28,16412,32796,49180, 29,16413,32797,49181, 30,16414,32798,49182, 31,16415
dw 32799,49183, 32,16416,32800,49184, 33,16417,32801,49185, 34,16418,32802,49186
dw 35,16419,32803,49187, 36,16420,32804,49188, 37,16421,32805,49189, 38,16422
dw 32806,49190, 39,16423,32807,49191, 40,16424,32808,49192, 41,16425,32809,49193
dw 42,16426,32810,49194, 43,16427,32811,49195, 44,16428,32812,49196, 45,16429
dw 32813,49197, 46,16430,32814,49198, 47,16431,32815,49199, 48,16432,32816,49200
dw 49,16433,32817,49201, 50,16434,32818,49202, 51,16435,32819,49203, 52,16436
dw 32820,49204, 53,16437,32821,49205, 54,16438,32822,49206, 55,16439,32823,49207
dw 56,16440,32824,49208, 57,16441,32825,49209, 58,16442,32826,49210, 59,16443
dw 32827,49211, 60,16444,32828,49212, 61,16445,32829,49213, 62,16446,32830,49214
dw 63,16447,32831,49215
LABEL shiftdata3 WORD
dw 0, 8192,16384,24576,32768,40960,49152,57344, 1, 8193,16385,24577,32769,40961
dw 49153,57345, 2, 8194,16386,24578,32770,40962,49154,57346, 3, 8195,16387,24579
dw 32771,40963,49155,57347, 4, 8196,16388,24580,32772,40964,49156,57348, 5, 8197
dw 16389,24581,32773,40965,49157,57349, 6, 8198,16390,24582,32774,40966,49158,57350
dw 7, 8199,16391,24583,32775,40967,49159,57351, 8, 8200,16392,24584,32776,40968
dw 49160,57352, 9, 8201,16393,24585,32777,40969,49161,57353, 10, 8202,16394,24586
dw 32778,40970,49162,57354, 11, 8203,16395,24587,32779,40971,49163,57355, 12, 8204
dw 16396,24588,32780,40972,49164,57356, 13, 8205,16397,24589,32781,40973,49165,57357
dw 14, 8206,16398,24590,32782,40974,49166,57358, 15, 8207,16399,24591,32783,40975
dw 49167,57359, 16, 8208,16400,24592,32784,40976,49168,57360, 17, 8209,16401,24593
dw 32785,40977,49169,57361, 18, 8210,16402,24594,32786,40978,49170,57362, 19, 8211
dw 16403,24595,32787,40979,49171,57363, 20, 8212,16404,24596,32788,40980,49172,57364
dw 21, 8213,16405,24597,32789,40981,49173,57365, 22, 8214,16406,24598,32790,40982
dw 49174,57366, 23, 8215,16407,24599,32791,40983,49175,57367, 24, 8216,16408,24600
dw 32792,40984,49176,57368, 25, 8217,16409,24601,32793,40985,49177,57369, 26, 8218
dw 16410,24602,32794,40986,49178,57370, 27, 8219,16411,24603,32795,40987,49179,57371
dw 28, 8220,16412,24604,32796,40988,49180,57372, 29, 8221,16413,24605,32797,40989
dw 49181,57373, 30, 8222,16414,24606,32798,40990,49182,57374, 31, 8223,16415,24607
dw 32799,40991,49183,57375
LABEL shiftdata4 WORD
dw 0, 4096, 8192,12288,16384,20480,24576,28672,32768,36864,40960,45056,49152,53248
dw 57344,61440, 1, 4097, 8193,12289,16385,20481,24577,28673,32769,36865,40961,45057
dw 49153,53249,57345,61441, 2, 4098, 8194,12290,16386,20482,24578,28674,32770,36866
dw 40962,45058,49154,53250,57346,61442, 3, 4099, 8195,12291,16387,20483,24579,28675
dw 32771,36867,40963,45059,49155,53251,57347,61443, 4, 4100, 8196,12292,16388,20484
dw 24580,28676,32772,36868,40964,45060,49156,53252,57348,61444, 5, 4101, 8197,12293
dw 16389,20485,24581,28677,32773,36869,40965,45061,49157,53253,57349,61445, 6, 4102
dw 8198,12294,16390,20486,24582,28678,32774,36870,40966,45062,49158,53254,57350,61446
dw 7, 4103, 8199,12295,16391,20487,24583,28679,32775,36871,40967,45063,49159,53255
dw 57351,61447, 8, 4104, 8200,12296,16392,20488,24584,28680,32776,36872,40968,45064
dw 49160,53256,57352,61448, 9, 4105, 8201,12297,16393,20489,24585,28681,32777,36873
dw 40969,45065,49161,53257,57353,61449, 10, 4106, 8202,12298,16394,20490,24586,28682
dw 32778,36874,40970,45066,49162,53258,57354,61450, 11, 4107, 8203,12299,16395,20491
dw 24587,28683,32779,36875,40971,45067,49163,53259,57355,61451, 12, 4108, 8204,12300
dw 16396,20492,24588,28684,32780,36876,40972,45068,49164,53260,57356,61452, 13, 4109
dw 8205,12301,16397,20493,24589,28685,32781,36877,40973,45069,49165,53261,57357,61453
dw 14, 4110, 8206,12302,16398,20494,24590,28686,32782,36878,40974,45070,49166,53262
dw 57358,61454, 15, 4111, 8207,12303,16399,20495,24591,28687,32783,36879,40975,45071
dw 49167,53263,57359,61455
LABEL shiftdata5 WORD
dw 0, 2048, 4096, 6144, 8192,10240,12288,14336,16384,18432,20480,22528,24576,26624
dw 28672,30720,32768,34816,36864,38912,40960,43008,45056,47104,49152,51200,53248,55296
dw 57344,59392,61440,63488, 1, 2049, 4097, 6145, 8193,10241,12289,14337,16385,18433
dw 20481,22529,24577,26625,28673,30721,32769,34817,36865,38913,40961,43009,45057,47105
dw 49153,51201,53249,55297,57345,59393,61441,63489, 2, 2050, 4098, 6146, 8194,10242
dw 12290,14338,16386,18434,20482,22530,24578,26626,28674,30722,32770,34818,36866,38914
dw 40962,43010,45058,47106,49154,51202,53250,55298,57346,59394,61442,63490, 3, 2051
dw 4099, 6147, 8195,10243,12291,14339,16387,18435,20483,22531,24579,26627,28675,30723
dw 32771,34819,36867,38915,40963,43011,45059,47107,49155,51203,53251,55299,57347,59395
dw 61443,63491, 4, 2052, 4100, 6148, 8196,10244,12292,14340,16388,18436,20484,22532
dw 24580,26628,28676,30724,32772,34820,36868,38916,40964,43012,45060,47108,49156,51204
dw 53252,55300,57348,59396,61444,63492, 5, 2053, 4101, 6149, 8197,10245,12293,14341
dw 16389,18437,20485,22533,24581,26629,28677,30725,32773,34821,36869,38917,40965,43013
dw 45061,47109,49157,51205,53253,55301,57349,59397,61445,63493, 6, 2054, 4102, 6150
dw 8198,10246,12294,14342,16390,18438,20486,22534,24582,26630,28678,30726,32774,34822
dw 36870,38918,40966,43014,45062,47110,49158,51206,53254,55302,57350,59398,61446,63494
dw 7, 2055, 4103, 6151, 8199,10247,12295,14343,16391,18439,20487,22535,24583,26631
dw 28679,30727,32775,34823,36871,38919,40967,43015,45063,47111,49159,51207,53255,55303
dw 57351,59399,61447,63495
LABEL shiftdata6 WORD
dw 0, 1024, 2048, 3072, 4096, 5120, 6144, 7168, 8192, 9216,10240,11264,12288,13312
dw 14336,15360,16384,17408,18432,19456,20480,21504,22528,23552,24576,25600,26624,27648
dw 28672,29696,30720,31744,32768,33792,34816,35840,36864,37888,38912,39936,40960,41984
dw 43008,44032,45056,46080,47104,48128,49152,50176,51200,52224,53248,54272,55296,56320
dw 57344,58368,59392,60416,61440,62464,63488,64512, 1, 1025, 2049, 3073, 4097, 5121
dw 6145, 7169, 8193, 9217,10241,11265,12289,13313,14337,15361,16385,17409,18433,19457
dw 20481,21505,22529,23553,24577,25601,26625,27649,28673,29697,30721,31745,32769,33793
dw 34817,35841,36865,37889,38913,39937,40961,41985,43009,44033,45057,46081,47105,48129
dw 49153,50177,51201,52225,53249,54273,55297,56321,57345,58369,59393,60417,61441,62465
dw 63489,64513, 2, 1026, 2050, 3074, 4098, 5122, 6146, 7170, 8194, 9218,10242,11266
dw 12290,13314,14338,15362,16386,17410,18434,19458,20482,21506,22530,23554,24578,25602
dw 26626,27650,28674,29698,30722,31746,32770,33794,34818,35842,36866,37890,38914,39938
dw 40962,41986,43010,44034,45058,46082,47106,48130,49154,50178,51202,52226,53250,54274
dw 55298,56322,57346,58370,59394,60418,61442,62466,63490,64514, 3, 1027, 2051, 3075
dw 4099, 5123, 6147, 7171, 8195, 9219,10243,11267,12291,13315,14339,15363,16387,17411
dw 18435,19459,20483,21507,22531,23555,24579,25603,26627,27651,28675,29699,30723,31747
dw 32771,33795,34819,35843,36867,37891,38915,39939,40963,41987,43011,44035,45059,46083
dw 47107,48131,49155,50179,51203,52227,53251,54275,55299,56323,57347,58371,59395,60419
dw 61443,62467,63491,64515
LABEL shiftdata7 WORD
dw 0, 512, 1024, 1536, 2048, 2560, 3072, 3584, 4096, 4608, 5120, 5632, 6144, 6656
dw 7168, 7680, 8192, 8704, 9216, 9728,10240,10752,11264,11776,12288,12800,13312,13824
dw 14336,14848,15360,15872,16384,16896,17408,17920,18432,18944,19456,19968,20480,20992
dw 21504,22016,22528,23040,23552,24064,24576,25088,25600,26112,26624,27136,27648,28160
dw 28672,29184,29696,30208,30720,31232,31744,32256,32768,33280,33792,34304,34816,35328
dw 35840,36352,36864,37376,37888,38400,38912,39424,39936,40448,40960,41472,41984,42496
dw 43008,43520,44032,44544,45056,45568,46080,46592,47104,47616,48128,48640,49152,49664
dw 50176,50688,51200,51712,52224,52736,53248,53760,54272,54784,55296,55808,56320,56832
dw 57344,57856,58368,58880,59392,59904,60416,60928,61440,61952,62464,62976,63488,64000
dw 64512,65024, 1, 513, 1025, 1537, 2049, 2561, 3073, 3585, 4097, 4609, 5121, 5633
dw 6145, 6657, 7169, 7681, 8193, 8705, 9217, 9729,10241,10753,11265,11777,12289,12801
dw 13313,13825,14337,14849,15361,15873,16385,16897,17409,17921,18433,18945,19457,19969
dw 20481,20993,21505,22017,22529,23041,23553,24065,24577,25089,25601,26113,26625,27137
dw 27649,28161,28673,29185,29697,30209,30721,31233,31745,32257,32769,33281,33793,34305
dw 34817,35329,35841,36353,36865,37377,37889,38401,38913,39425,39937,40449,40961,41473
dw 41985,42497,43009,43521,44033,44545,45057,45569,46081,46593,47105,47617,48129,48641
dw 49153,49665,50177,50689,51201,51713,52225,52737,53249,53761,54273,54785,55297,55809
dw 56321,56833,57345,57857,58369,58881,59393,59905,60417,60929,61441,61953,62465,62977
dw 63489,64001,64513,65025
shifttabletable dw shiftdata0,shiftdata1,shiftdata2,shiftdata3
dw shiftdata4,shiftdata5,shiftdata6,shiftdata7
PUBLIC shifttabletable
;============================================================================
CODESEG
IFE GRMODE-CGAGR
INCLUDE "ID_VW_AC.ASM"
ENDIF
IFE GRMODE-EGAGR
INCLUDE "ID_VW_AE.ASM"
ENDIF
IFE GRMODE-VGAGR
INCLUDE "ID_VW_AV.ASM"
ENDIF
;============================================================================
;
; MISC VIDEO ROUTINES
;
;============================================================================
;========
;
; VW_WaitVBL (int number)
;
;========
PROC VW_WaitVBL number:WORD
PUBLIC VW_WaitVBL
if WAITFORVBL ; skip wait if profiling
mov dx,STATUS_REGISTER_1
mov cx,[number]
waitvbl1:
in al,dx
test al,00001000b ;look for vbl
jnz waitvbl1
waitvbl2:
in al,dx
test al,00001000b ;look for vbl
jz waitvbl2
loop waitvbl1
endif
ret
ENDP
;===========================================================================
MASM
;ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ
;
; Name: VW_VideoID
;
; Function: Detects the presence of various video subsystems
;
; int VideoID;
;
; Subsystem ID values:
; 0 = (none)
; 1 = MDA
; 2 = CGA
; 3 = EGA
; 4 = MCGA
; 5 = VGA
; 80h = HGC
; 81h = HGC+
; 82h = Hercules InColor
;
;ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ
;ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ
;
; Equates
;
;ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ
VIDstruct STRUC ; corresponds to C data structure
Video0Type DB ? ; first subsystem type
Display0Type DB ? ; display attached to first subsystem
Video1Type DB ? ; second subsystem type
Display1Type DB ? ; display attached to second subsystem
VIDstruct ENDS
Device0 EQU word ptr Video0Type[di]
Device1 EQU word ptr Video1Type[di]
MDA EQU 1 ; subsystem types
CGA EQU 2
EGA EQU 3
MCGA EQU 4
VGA EQU 5
HGC EQU 80h
HGCPlus EQU 81h
InColor EQU 82h
MDADisplay EQU 1 ; display types
CGADisplay EQU 2
EGAColorDisplay EQU 3
PS2MonoDisplay EQU 4
PS2ColorDisplay EQU 5
TRUE EQU 1
FALSE EQU 0
;ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ
;
; Program
;
;ÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍÍ
Results VIDstruct <> ;results go here!
EGADisplays DB CGADisplay ; 0000b, 0001b (EGA switch values)
DB EGAColorDisplay ; 0010b, 0011b
DB MDADisplay ; 0100b, 0101b
DB CGADisplay ; 0110b, 0111b
DB EGAColorDisplay ; 1000b, 1001b
DB MDADisplay ; 1010b, 1011b
DCCtable DB 0,0 ; translate table for INT 10h func 1Ah
DB MDA,MDADisplay
DB CGA,CGADisplay
DB 0,0
DB EGA,EGAColorDisplay
DB EGA,MDADisplay
DB 0,0
DB VGA,PS2MonoDisplay
DB VGA,PS2ColorDisplay
DB 0,0
DB MCGA,EGAColorDisplay
DB MCGA,PS2MonoDisplay
DB MCGA,PS2ColorDisplay
TestSequence DB TRUE ; this list of flags and addresses
DW FindPS2 ; determines the order in which this
; program looks for the various
EGAflag DB ? ; subsystems
DW FindEGA
CGAflag DB ?
DW FindCGA
Monoflag DB ?
DW FindMono
NumberOfTests EQU ($-TestSequence)/3
PUBLIC VW_VideoID
VW_VideoID PROC
push bp ; preserve caller registers
mov bp,sp
push ds
push si
push di
push cs
pop ds
ASSUME DS:@Code
; initialize the data structure that will contain the results
lea di,Results ; DS:DI -> start of data structure
mov Device0,0 ; zero these variables
mov Device1,0
; look for the various subsystems using the subroutines whose addresses are
; tabulated in TestSequence; each subroutine sets flags in TestSequence
; to indicate whether subsequent subroutines need to be called
mov byte ptr CGAflag,TRUE
mov byte ptr EGAflag,TRUE
mov byte ptr Monoflag,TRUE
mov cx,NumberOfTests
mov si,offset TestSequence
@@L01: lodsb ; AL := flag
test al,al
lodsw ; AX := subroutine address
jz @@L02 ; skip subroutine if flag is false
push si
push cx
call ax ; call subroutine to detect subsystem
pop cx
pop si
@@L02: loop @@L01
; determine which subsystem is active
call FindActive
mov al,Results.Video0Type
mov ah,0 ; was: Results.Display0Type
pop di ; restore caller registers and return
pop si
pop ds
mov sp,bp
pop bp
ret
VW_VideoID ENDP
;
; FindPS2
;
; This subroutine uses INT 10H function 1Ah to determine the video BIOS
; Display Combination Code (DCC) for each video subsystem present.
;
FindPS2 PROC near
mov ax,1A00h
int 10h ; call video BIOS for info
cmp al,1Ah
jne @@L13 ; exit if function not supported (i.e.,
; no MCGA or VGA in system)
; convert BIOS DCCs into specific subsystems & displays
mov cx,bx
xor bh,bh ; BX := DCC for active subsystem
or ch,ch
jz @@L11 ; jump if only one subsystem present
mov bl,ch ; BX := inactive DCC
add bx,bx
mov ax,[bx+offset DCCtable]
mov Device1,ax
mov bl,cl
xor bh,bh ; BX := active DCC
@@L11: add bx,bx
mov ax,[bx+offset DCCtable]
mov Device0,ax
; reset flags for subsystems that have been ruled out
mov byte ptr CGAflag,FALSE
mov byte ptr EGAflag,FALSE
mov byte ptr Monoflag,FALSE
lea bx,Video0Type[di] ; if the BIOS reported an MDA ...
cmp byte ptr [bx],MDA
je @@L12
lea bx,Video1Type[di]
cmp byte ptr [bx],MDA
jne @@L13
@@L12: mov word ptr [bx],0 ; ... Hercules can't be ruled out
mov byte ptr Monoflag,TRUE
@@L13: ret
FindPS2 ENDP
;
; FindEGA
;
; Look for an EGA. This is done by making a call to an EGA BIOS function
; which doesn't exist in the default (MDA, CGA) BIOS.
FindEGA PROC near ; Caller: AH = flags
; Returns: AH = flags
; Video0Type and
; Display0Type updated
mov bl,10h ; BL := 10h (return EGA info)
mov ah,12h ; AH := INT 10H function number
int 10h ; call EGA BIOS for info
; if EGA BIOS is present,
; BL <> 10H
; CL = switch setting
cmp bl,10h
je @@L22 ; jump if EGA BIOS not present
mov al,cl
shr al,1 ; AL := switches/2
mov bx,offset EGADisplays
xlat ; determine display type from switches
mov ah,al ; AH := display type
mov al,EGA ; AL := subystem type
call FoundDevice
cmp ah,MDADisplay
je @@L21 ; jump if EGA has a monochrome display
mov CGAflag,FALSE ; no CGA if EGA has color display
jmp short @@L22
@@L21: mov Monoflag,FALSE ; EGA has a mono display, so MDA and
; Hercules are ruled out
@@L22: ret
FindEGA ENDP
;
; FindCGA
;
; This is done by looking for the CGA's 6845 CRTC at I/O port 3D4H.
;
FindCGA PROC near ; Returns: VIDstruct updated
mov dx,3D4h ; DX := CRTC address port
call Find6845
jc @@L31 ; jump if not present
mov al,CGA
mov ah,CGADisplay
call FoundDevice
@@L31: ret
FindCGA ENDP
;
; FindMono
;
; This is done by looking for the MDA's 6845 CRTC at I/O port 3B4H. If
; a 6845 is found, the subroutine distinguishes between an MDA
; and a Hercules adapter by monitoring bit 7 of the CRT Status byte.
; This bit changes on Hercules adapters but does not change on an MDA.
;
; The various Hercules adapters are identified by bits 4 through 6 of
; the CRT Status value:
;
; 000b = HGC
; 001b = HGC+
; 101b = InColor card
;
FindMono PROC near ; Returns: VIDstruct updated
mov dx,3B4h ; DX := CRTC address port
call Find6845
jc @@L44 ; jump if not present
mov dl,0BAh ; DX := 3BAh (status port)
in al,dx
and al,80h
mov ah,al ; AH := bit 7 (vertical sync on HGC)
mov cx,8000h ; do this 32768 times
@@L41: in al,dx
and al,80h ; isolate bit 7
cmp ah,al
loope @@L41 ; wait for bit 7 to change
jne @@L42 ; if bit 7 changed, it's a Hercules
mov al,MDA ; if bit 7 didn't change, it's an MDA
mov ah,MDADisplay
call FoundDevice
jmp short @@L44
@@L42: in al,dx
mov dl,al ; DL := value from status port
and dl,01110000b ; mask bits 4 thru 6
mov ah,MDADisplay ; assume it's a monochrome display
mov al,HGCPlus ; look for an HGC+
cmp dl,00010000b
je @@L43 ; jump if it's an HGC+
mov al,HGC ; look for an InColor card or HGC
cmp dl,01010000b
jne @@L43 ; jump if it's not an InColor card
mov al,InColor ; it's an InColor card
mov ah,EGAColorDisplay
@@L43: call FoundDevice
@@L44: ret
FindMono ENDP
;
; Find6845
;
; This routine detects the presence of the CRTC on a MDA, CGA or HGC.
; The technique is to write and read register 0Fh of the chip (cursor
; low). If the same value is read as written, assume the chip is
; present at the specified port addr.
;
Find6845 PROC near ; Caller: DX = port addr
; Returns: cf set if not present
mov al,0Fh
out dx,al ; select 6845 reg 0Fh (Cursor Low)
inc dx
in al,dx ; AL := current Cursor Low value
mov ah,al ; preserve in AH
mov al,66h ; AL := arbitrary value
out dx,al ; try to write to 6845
mov cx,100h
@@L51: loop @@L51 ; wait for 6845 to respond
in al,dx
xchg ah,al ; AH := returned value
; AL := original value
out dx,al ; restore original value
cmp ah,66h ; test whether 6845 responded
je @@L52 ; jump if it did (cf is reset)
stc ; set carry flag if no 6845 present
@@L52: ret
Find6845 ENDP
;
; FindActive
;
; This subroutine stores the currently active device as Device0. The
; current video mode determines which subsystem is active.
;
FindActive PROC near
cmp word ptr Device1,0
je @@L63 ; exit if only one subsystem
cmp Video0Type[di],4 ; exit if MCGA or VGA present
jge @@L63 ; (INT 10H function 1AH
cmp Video1Type[di],4 ; already did the work)
jge @@L63
mov ah,0Fh
int 10h ; AL := current BIOS video mode
and al,7
cmp al,7 ; jump if monochrome
je @@L61 ; (mode 7 or 0Fh)
cmp Display0Type[di],MDADisplay
jne @@L63 ; exit if Display0 is color
jmp short @@L62
@@L61: cmp Display0Type[di],MDADisplay
je @@L63 ; exit if Display0 is monochrome
@@L62: mov ax,Device0 ; make Device0 currently active
xchg ax,Device1
mov Device0,ax
@@L63: ret
FindActive ENDP
;
; FoundDevice
;
; This routine updates the list of subsystems.
;
FoundDevice PROC near ; Caller: AH = display #
; AL = subsystem #
; Destroys: BX
lea bx,Video0Type[di]
cmp byte ptr [bx],0
je @@L71 ; jump if 1st subsystem
lea bx,Video1Type[di] ; must be 2nd subsystem
@@L71: mov [bx],ax ; update list entry
ret
FoundDevice ENDP
IDEAL
END
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