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Assembly Source File | 1990-11-29 | 16.5 KB | 400 lines

;«RM82»«TS8,16,24,32,40,48,56,64» ; Updated 11/20/90 ;======================================================================= ; Copyright (C) Copr. 1990 by Sidney J. Kelly ; All Rights Reserved. ; Sidney J. Kelly ; 150 Woodhaven Drive ; Pittsburgh, PA 15228 ; home phone 412-561-0950 (7pm to 9:30pm EST) ;----------------------------------------------------------------------- ; Function prototype in QBASIC ; DECLARE FUNCTION VideoStat% () ; ; VideoStatus Analyzer ; Program returns video information for use by QBASIC ; returns highest level of SCREEN mode supported by the Hardware. ; Returns information about the PRIMARY display only ; This routine with a select case, can tell you how many display pages ; are available in text mode, SCREEN 0: ; VGA has 8 pages ; EGA with > 64kb has 8 pages ; EGA with 64kb has 4 pages ; CGA has 4 pages ; MONO has 1 pages ; HERC has 1 page in SCREEN 0, 2 pages in SCREEN 3 ; ; Exceptions: ; MCGA color returns a mode 11, so can contrast w/ VGA ; HERC w/o MSHERC.COM reports a -3 so you can tell user to correct matters ; COMPAQ with CGA reports -2 so can force use of monchrome attributes. ; EGA's with CGA diplays report -8 if have only 64kb of memory ; EGA's with ECD display report 8 if have only 64kb of memory ; ; Returns: ; Mono = 0 ; CGA = 2 ; PGA = 2 (Untested, assume PGA would be treated as CGA) ; COMPAQ - CGA = -2 to tell that user may have a single color display ; HERC = 3 if have HERC and MSHERC.COM ; HERC = -3 if have HERC but w/o MSHERC.COM ; AT&T = 4, but only if have just CGA display, not EGA or VGA ; Microsoft QuickC/C makes Olivetti EGA and VGA return a separate code. ; I don't know why anyone would care if the EGA/VGA emulation were ; good. ; ; EGA64 = 8 Because resolution limited for 64k EGA ; EGA64 w/CGA = -8 Because resolution limited to CGA modes ; EGA = 9 Have minimum of 128kb of video ram ; EGA w/CGA = -9 Since resolution limited to CGA modes ; MCGA = 11 If have an analog color display ; MCGA = -11 If have an EGA ECD digital color display, since ; resolution of this display is limited to EGA modes ; VGA = 13 ; EGA/VGA mono = 10 I guess will catch MCGA mono too ; ; Version 0.92 ; ; Tested: CGA, HERC clone, EGA mono, EGA color, VGA color, COMPAQ CGA, ; VGA clone, EGA clone (Paradise clone, ATI EGA Wonder), AT&T 6300 ; Not tested: PGA, VGA monochrome, MCGA (color or monochrome) ;======================================================================= DOSSEG ;I have had problems unless this is used .model medium ;I use QUICK C / QUICK ASM which uses MASM 5.1 simplified .code ;directives public VIDEOSTAT HERC_PORT Equ 03bah ; Herc display status port COMPAQ DB 'COMPAQ' ; BIOS ID string in COMPAQ's COMPAQ_LEN Equ 6 ; length of string ;Following is commented out because alternative method is faster ;ATT DB 'OLIVETTI' ; BIOS ID string for OLIVETTI/AT&T ;ATT_LEN Equ 8 ; length of string ; Please do not remove Copyright DB 13,10,'Copyright Copr. (C) 1990 Sidney J. Kelly',13,10 Copyright1 DB 'All Rights Reserved',13,10,26 EVEN VIDEOSTAT PROC far Push BP ; save BP because old PC Video BIOS ; didn't necessarily preserve this Push DI ; QBASIC requires these 2 to be saved Push SI ; this just tests for primary display vgatest: ; because that is all QBASIC cares about Mov AX,1A00h Mov BX,10h ; Test for VGA adapter Int 10h Cmp AL,1Ah ; If VGA adapter exists, it returns AL=1Ah Jne egatest ; VGA does not exist so test for EGA ; Else VGA exists, primary display info Cmp BL,8 ; routine returns primary display in BL Jne @F Jmp Short vga_color ; VGA color exists. This does not test ; if VGA adapter clone is in emulation ; mode, such as HERC emulation ; because QBASIC does not check ; for this either. @@: Cmp BL,7 Jne @f Jmp vga_mono ; VGA mono exists, no effort is made to ; distinguish between VGA, EGA or MCGA mono @@: Cmp BL,11 Jne @f Jmp vga_mono ; MCGA mono exists @@: Cmp BL,12 Jne @f Jmp Short mcga_color ; MCGA analog color exists @@: Cmp BL,10 Jne @f Jmp Short mcga_ecd ; MCGA w/EGA display (untested) @@: Cmp BL,4 ; EGA color screen found, we have to Jne @f ; test if EGA is attached to ECD Jmp Short egatest ; monitor or just plain CGA monitor @@: Cmp BL,5 Jne @f Jmp Short vga_mono ; EGA mono screen found @@: Cmp BL,2 Jne @F Jmp Short att_test ; CGA color found, test for which type @@: Cmp BL,1 Jne @f Jmp herctest ; MDA mono found @@: Cmp BL,6 ; test for PGA, treat as a CGA Jne @f Jmp cga ; I guess this should work, untested @@: ; With everything else Jmp unknown ; merely assume can do normal b&w text egatest: Mov AX,1200h Mov BX,10h Int 10h Cmp BL,10h ; EGA changes BL from 10h Je cgatest Mov DX,BX ; Save BX temporarily in DX Xor BX,BX Mov ES,BX Test ES:Byte Ptr [487h],1000b ;EGA active?, bit 3 of 0040:0087 set? JZ EGA_active ; if bit clear, then EGA is active Jmp Short cgatest ; else if EGA not active (primary) check CGA EGA_active: Mov BX,DX ; get former value back from CX Or BH,BH ; if BH = 1 then have MONO display JZ ega_color ; else have color display Jmp Short vga_mono ; treat as a VGA mono vga_color: Mov AX,13 ; max screen mode is QBASIC SCREEN 13 Jmp Quit mcga_color: Mov AX,11 ; near max screen mode is QBASIC SCREEN 11 Jmp Quit ; MCGA can do SCREEN 13 too, but not 12. mcga_ecd: Mov AX,-11 ; a warning that MCGA has EGA display Jmp short Quit ; attached (Untested) ega_color: ;*********** Based on information returned by AH 12h, BL 10h of INT 10h, ;*********** this routine reads the EGA Sense switches stored in CL ;*********** to see if really have a primary monitor that can do EGA graphics. ;*********** If do not have an ECD/multisync display, report a -9. ;*********** If have a 64kb EGA reports 8 if have ECD or -8 if have CGA ;*********** It is unclear if this will work on all clone EGA's. ;*********** It works with a VGA clone and ATI EGA Wonder as well as an ;*********** ACER EGA clone. ;*********** CL information derived from RAM memory at 0040:0088h ;*********** ;*********** Source of CL information: ;*********** Ferro, "Programmer's Guide to the EGA and VGA Cards," ;*********** (Addison-Wesley 1988), page 337. Yet on page 473 says you can't ;*********** tell what CL will report. ;*********** Similar information hidden in Wilton, "Programmer's Guide to ;*********** PC & PS/2 Video Systems" (Microsoft 1987), page 520. ;*********** ;*********** Partial information set forth in Phoenix's "System Bios for ;*********** PC/XT/AT Computers and Compatibles (Addison-Wesley 1989) ;*********** page 243 (which states that VGA's follow this too) ;*********** ;*********** Wilton's routine also appears in other books, e.g. ;*********** Tischer, "PC System Programming for Developers" (ABACUS 1989) ;*********** page 542 ;*********** ;*********** See also, Woram, "PC Configuration Book" (Bantam 1987), ;*********** pages 279-280 Provides listing of IBM official switch ;*********** settings which does not seem to match anything ;*********** in the above two books. ;*********** ;*********** CL returns on good clones: ;*********** EGA inactive w/ MDA primary = 00h, 01h, 02h, 03h ;*********** EGA inactive w/ CGA primary = 04h, 05h ;*********** EGA active w/ CGA = 06h, 07h ;*********** EGA active w/ ECD in CGA mode = 08h ;*********** EGA active w/ ECD = 09h ;*********** EGA active w/ MDA mono = 0Bh, 0Ah Cmp CL,9 ; read EGA Sense switches to see if ; have ECD display and not a CGA display JE ega1 Mov AX,-9 ; report have a CGA type display Or BL,BL ; check if BL=0, i.e. 64kb Memory JNZ @f ; nope so quit Inc AX ; report have a CGA display w/ 64kb Memory @@: Jmp short Quit ; with an EGA adapter ega1: Mov AX,9 ; max screen mode is QBASIC SCREEN 9 Or BL,BL ; check if BL = 0, i.e. 64kb memory JNZ @f ; nope, so quit Dec AX ; report have EGA w/ ECD display ; but only 64KB memory (makes 9 an 8) @@: Jmp Short Quit vga_mono: Mov AX,10 ; max screen mode is QBASIC SCREEN 10 Jmp Short Quit ; may also be a MCGA or EGA mono too. ; since QBASIC does not distinguish ; I don't either cgatest: Xor AX,AX Mov ES,AX Mov BX,ES:[0463h] ; check if MONO port in use Cmp BL,0B4h Je herctest ; this test looks for Mono port address att_test: ;******* The AT&T CGA is just a CGA that responds to a special mode set ;******* command. Mode 48h is equivalent to SCREEN 4. It is possible ;******* to load BIOS ram with this screen mode and fool QBASIC. Try it and ;******* you will get some weird displays on non-AT&T displays. ;******* Unknown if that "gamemanship" may hurt your monitor. ;******* ;******* Cannot merely attempt to change to mode &H48 to test for AT&T ;******* because some old CGA's (e.g. Tecmar Color Graphics Card) will let you ;******* change mode number to anything you try. However HERC clones, ;******* EGA clones and VGA clones will only allow a change to a supported ;******* video mode so such a test would work with them, but would be ;******* worthless unless you could be confident that all CGA's were new. Mov AX,0F000h ; Get ROM ID segment Mov ES,AX ; Store segment in ES CLD ; clear the direction flag Push DS ; Save DS Mov AX,CS Mov DS,AX ; set DS = to CS Assume DS:@code comment |* ; this is the long form routine, using full name Mov DI,0C050h ; point DI at ROM Mov SI,OFFSET ATT ; DS:SI points to "OLIVETTI". Mov CX,ATT_LEN ; CX has length of "OLIVETTI". REPE CMPSB ; ES:DI destination, DS:SI source Jne compaq_test ; if no change test for COMPAQ |* ; faster version ; Source: XMS.SYS version 2.06 MASM source Cmp ES:[0C05h],'LO' ; look for byte reversed 'OL' at FC00:0050h ; in memory letters are reversed Jne compaq_test ; COMPAQ not found att_found: ; program assumes that if a CGA is active on an AT&T ; that built-in adapter is in use. Pop DS ; restore DS Assume DS:@data Mov AX,4 ; max screen mode is QBASIC SCREEN 4 Jmp Short Quit compaq_test: ; Purpose of this test is to allow other routines to know if ; "snow" testing is necessary, as well as to tell programmer ; to use mono attributes in program rather than color attributes ; which would confuse the viewer of a COMPAQ single color display. ; source: XMS.SYS Version 2.06 MASM Source Code Mov DI,0FFEAh ; Get ID offset & store in DI Mov SI,OFFSET COMPAQ ; DS:SI points to "COMPAQ". Mov CX,COMPAQ_LEN ; CX has length of "COMPAQ". REP CMPSB ; ES:DI destination, DS:SI source Pop DS ; restore DS Assume DS:@data ; Program assumes that if a CGA is active on a COMPAQ ; that built-in single color display is in use because ; even though it does not have color it has better ; text resoluton. Mov AX,-2 ; assume found COMPAQ CGA mode ; to tell us that user likely has a ; single color display JE found_compaq ; if match found cga: ; Normal CGA Mov AX,2 ; max screen mode is QBASIC SCREEN 2 found_compaq: Jmp Short Quit herctest: ;*****Main Herc test entry point**** ; Herc display changes Vertical retrace bit during vertical retrace ; however normal MDA display does not. ; Source for HERC test only: ; Hercules Computer Technology, Inc. and Doty, ; "Programmer's Guide to Hercules Graphics Cards" ; (Addison-Wesley 1988) page 138. ; Similar routines have been published in PC Magazine ; and Young, "Inside DOS: A Programmer's Guide", (Sybex 1990) ; page 178, as well as Young's book on OS/2. ; ; No effort is made to test for Herc INCOLOR or any other HERC ; displays since QBASIC would not use the information. ; If you must have it, see Doty or Wilton's books listed above. ; test the HERC_Port Mov DX,HERC_PORT ; load DX with display status port ; a Read-only port Xor BX,BX ; clear counter IN AL,DX ; read port And AL,80h ; mask off every bit but bit 7 Mov AH,AL ; store in AH original status of bit Mov CX,8000h ; load loop counter herc1: IN AL,DX ; read byte And AL,80h ; clear everything but bit 7 Cmp AL,AH ; keep testing for change in bit 7 Je herc2 Inc BL ; for every change Inc BL Cmp BL,12 ; check routine found vertical ; retrace changed 12 times JA Test_4_MSHERC ; found a herc so test for MSHERC.COM herc2: Loop herc1 ; Herc display not found unknown: ; Handles mono displays too Xor AX,AX ; return a 0 if just normal text display EVEN Quit: Pop SI ; restore saved registers Pop DI Pop BP Ret Test_4_MSHERC: Mov AX,0EF00h ; test for MSHERC.COM Int 10h Mov AX,3 ; Assume max screen mode is QBASIC SCREEN 3 Cmp DX,0100h ; **this is an undocumented call and may ; change ******!!!!! JE Have_MSHerc ; if equal then MSHERC.COM is installed Mov AX,-3 ; else report MSHERC.COM is not installed ; return -3 Have_MSHerc: Jmp Short Quit VIDEOSTAT ENDP END ;---------------------------------------------------------------------- ; If you read this far, you are a scholar. If you really want a good ; video book I would suggest that you buy Michael Abrash's On Graphics ; book about EGA/VGA display's, published by QUE, very advanced. ; For useful information,-- what does this port do--, for all display ; types, Wilton's book is very good. Ferro's book has more specific ; EGA/VGA information but book is a little disorganized. ; Sidney J. Kelly ; 150 Woodhaven Drive ; Pittsburgh, PA 15228 ; home phone 412-561-0950 (7pm to 9:30pm EST) ;----------------------------------------------------------------------