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Article #565

Mode Y. I'm only a year behind :-)

#565
From: Mike Battersby
Date: Tue, 11 Aug 1992 07:54
37 lines
1950 bytes
	Since having only just recently discovered the joys of VGA
graphics, and still being a relative novice to the world of such,
I have a a question for those of you who can beat origin at their
own game :-) And if this seems annoying to anyone, well tough luck,
since I figured thats what an area like this is for, to learn things,
not just for hugely advanced discussion.

	Okay, the question is this.. How to set mode Y? I figure all
that you'd need to do is set mode 13 and then turn of chaining? Is
this right or is there more to it? I have seen the following code and
have wondered about it.

		mov ax,13h		; set ordinary 320x200 mode 13h
		int 10h

		mov dx,3d4h		; turn off doubleword mode
		mov ax,0014h
		out dx,ax

		mov dx,3c4h		; turn off chaining 
		mov ax,0604h
		out dx,ax


	Can someone please explain what the hell the
(a) double word and (b) Count by 4 bits do, and also how something
which in the books I've seen is called Odd/Even and Extenede Memory
(bits 2 and 1 of sequencer index 4) has to do with chaining?

--
         .-----------------------------------------------------------.
         | Mike Battersby  |  ins132g@aurora.cc.monash.edu.au        |
         |-----------------------------------------------------------|
         | 'Female?' The Cat looked at Lister.                       |
         | 'Is that "female" as in "soft and squidgy"?' - Red Dwarf  |
         `-----------------------------------------------------------'
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From: ins132g@aurora.cc.monash.edu.au (Mike Battersby)
Subject: Mode Y. I'm only a year behind :-)
Message-ID: <1992Aug11.075400.555@monu6.cc.monash.edu.au>
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Organization: Monash University
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Date: Tue, 11 Aug 1992 07:54:00 GMT
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