video memory segment

 BBS: Inland Empire Archive
Date: 05-27-92 (21:22)             Number: 158
From: MATT HART                    Refer#: NONE
  To: MARK BUTLER                   Recvd: NO  
Subj: video memory segment           Conf: (2) Quik_Bas

 > MB>   FUNCTION CRT%
 > JG>   I tried that on my monochrome monitor and it told me that I

 MB> ??? that's weird. I retested this again on my CGA (Crumby Graphics

Here's two algorithms for determining monitor type.  The
first is the memory location for the current screen mode:
color monitors start in 3 (SCREEN 0, WIDTH 80) but can
change; monochrome monitors should always register 7.

DEF SEG = 0
M = PEEK(&H0449)
DEF SEG
IF M = 7 THEN PRINT "Monochrome" ELSE PRINT "Color"

Here's another, and should be very reliable.  It's the
address of the CRT controller index register.  0000:0463h
=  B4h for monochrome and D4h for color.

DEF SEG = 0
M = PEEK(&H0463)
DEF SEG
IF M = &HB4 THEN PRINT "Monochrome" ELSE PRINT "Color"
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