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Conference 7.286::atarist

Title:Atari ST, TT, & Falcon
Notice:Please read note 1.0 and its replies before posting!
Moderator:FUNYET::ANDERSON
Created:Mon Apr 04 1988
Last Modified:Tue May 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:1433
Total number of notes:10312

78.0. "Blitterchip ??" by UTROP1::TRAMONTINA () Fri May 06 1988 07:12

    Hello,
    
    I was wondering what happened to the Blitterchip. Last year everything
    that was written about Atari was 'Blitter mania'. At the present
    nothing can be heard. Does somebody knows something more, and can
    he/she help me.
    
    For example:
    Is the Blitter shipped with the current Mega's? (it wasn't with
    the first shipments)
    How's the performance?
    
    Thanks in advance,
    
    Renato
T.RTitleUserPersonal
Name		DateLines
78.1not (yet) built inSUOSW1::KAISERHoly St. Asap !Fri May 06 1988 07:548
I have a MEGA ST for about 7 weeks now and this one has not been shipped
with a Blitter. Last week I asked my dealer when they would get them.
The answer was: "We're actually getting blitters from time to time, but not
the amounts we need for our sold MEGAs. So we call the people in the order
the bought their MEGAs to bring the machines to us to build the chip in."
They said in about 1 or 2 months it'll be my turn.

-Hans
78.2LDP::WEAVERLaboratory Data ProductsFri May 06 1988 22:345
    I discussed the performance back in an old note in the December
    1987 timeframe in the old conference.  My Mega 2 didn't come with
    one, but I had it within a few days when I upgraded back in December.
    
    						-Dave
78.3 BLITTER's REVISITEDKERNEL::GILLESPIEMon Dec 19 1988 13:4017
    
    Yet another visit to this question.
    
    Does anyone know the answer to the following questions.
    
    	1: Are BLITTERCHIPS available now or not.?
    
    	2: The 520STFM, has a socket for the BLITTERCHIP YES or NO.?
    
    	3: If the chips are available, how much and from whom.?
    
    Thanks in advance any info gratefully received.
    
    Nat.G.
78.4blitter maniaCIMBAD::POWERSI Dream Of Wires - G. NumanMon Dec 19 1988 13:4521

    RE: .3
    
>    	1: Are BLITTERCHIPS available now or not.?

        They are not available.
    
>    	2: The 520STFM, has a socket for the BLITTERCHIP YES or NO.?

        They do not
    
>    	3: If the chips are available, how much and from whom.?
    
>    Nat.G.

     Bill Powers
78.5Really No Sockets for BLITTERKERNEL::GILLESPIETue Dec 20 1988 08:4216
    
    RE:	.4
    
    	Thanks for quick response, now confused with regards to:
    
    >    	2: The 520STFM, has a socket for the BLITTERCHIP YES or NO.?

    >>        They do not
    
    	If the chips ar'nt available then this is academic, but
    nevertheless, at least two colleaques I talked with have indicated
    that the new REV of 520/1040 system board have a socket for the
    BLITTER, anyone else care to comment.
    
    Nat.G.
78.6Blit on ROM ??RDGENG::KEANETue Dec 20 1988 13:1013
    Hi Nat,
    
    I thought that there was confusion over this issue before. The theory
    that came out then was that there was an empty socket on some revs
    of PCB, but it was for an extra, (different size?) ,  TOS ROM. 
    
    Atari work in wonderous ways, so who knows.  Hey why is it the cursor
    has just vanished from this note reply. It's jolly hard typing without
    it!!
    
    Cheers
    
    Pat K
78.7Huh?DEMING::HLQARThu Dec 22 1988 10:185
    
    Pardon my ignorance ... but what is a blitter chip?
    
    Speedo the Confused
78.8Blitter ?DISCVR::FISTERPardon, my DMA isn't working...Thu Dec 22 1988 10:4912
    
    	A Blitter is a hardware reality of an old software method. It
    moves large amounts of info around the microproccesor instead of
    through it.
    	The Atari blitter is used for screen info, giving faster display
    output. When I picked up my Mega2, I was impressed by the speed
    difference.
    	...until I found that the blitter was off. In my opinion, I
    have never seen an earth-shattering difference with or without.
    
    						Les
78.9Oh, THAT blitter chip ...DEMING::HLQARThu Dec 22 1988 11:109
    
    So, you mean to say that it acts like a dedicated microprocessor
    (or _is_ one)?  That's not such a bad idea; I'm surprised that it
    had little impact on your machine's performance.  I supose that
    it would depend on how fast this chip runs.  Does anyone have any
    specific information (read 'data specs') on them?  I had never heard
    of them before today, and would like to hear more about them.
    
    Speedo the Enlightened
78.10BOLT::MINOWRepent! Godot is coming soon! Repent!Sun Dec 25 1988 22:2419
To put the graphics on the screen, you need to do a number of bit-level
data transfers.  They are fairly difficult (computationally) as the two
pieces of data might not be byte-aligned.  This means you are continually
shifting, bit-testing, bit-munging.  (The Atari-ST gets some speed for
mono-spaced text by defining its characters to be 8-bits wide, but nothing
helps proportionally-spaced text.)

The operations are collectively called Blit's (bit-block-transfers).
The best description (and sample code) I've found is in the Smalltalk
manuals.  I suspect there are others, of course.

The Blitter, I am told, implements the shift/logical-op/shift/write
using dedicated hardware.  It should be faster, especially if it can
clip the writing to the window structure (probably not the case).

You might be able to find a spec of the Atari Blitter's capabilities
in the developer's documentation (or by digging through the notesfile).

Martin.