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An error in "Mapping the Atari"?


jmccorm
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Something in Mapping the Atari [PDF, HTML] caught my eye...

DECIMAL HEX LABEL

558 22E CDTMF5

System timer five flag. Set when location 558, 559 ($22E, $22F)
counts down to zero.

This explanation doesn't make sense, because the description references another memory location, 558 ($22E), which is thie very same memory location which is being explained! Additionally, location 559 ($22F) controls DMA for the ANTIC and most certainly is NOT a timer.

 

I seem to remember also running into this as a kid and wondering if they made a mistake. I'm guessing they meant to reference locations 544, 545 ($220, $221) in the description instead of 558, 559 ($22E, $22F)?

Edited by jmccorm
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While the Altirra hardware manual is a great effort, Mapping the Atari feels more accessible when coming from a BASIC background. It would be another great project to edit all this info into an online Atari memory map which could have examples in multiple languages.

 

Or for starters, at least an errata sheet for MtA.

 

 

Gesendet von iPhone mit Tapatalk

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To be fair the hardware manual is exactly what it says, its not trying to be a memory map but yes, if you are looking for location info MTA works well but if you are looking for accurate detailed information about the Atari Hardware then Avery's manual works best.

 

Avery's is more like De Re Atari..

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I've been told or heard or read for the last 30 years from the community at large, that the two most important books for Atari are De Re Atari and Mapping the Atari (revised edition). I own these two and have PDF of several others. Admittedly, actually reading and referencing them is another thing. They are part of my bucket list of technical knowledge and programming reads though...but first, I'm learning SpartaDOS X. Of course there's not a lot of point in the knowledge from those books until I relearn at least BASIC, if not machine language or both first too.

Edited by Gunstar
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I'd head down the machine language route, well actually that's the exact route I took back in the day, could not get on with BASIC...Of course the clever one would be to learn both :)

 

A simple bit of basic with embedded ML data, the flexibility of BASIC with the speed of ML..

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I'd head down the machine language route, well actually that's the exact route I took back in the day, could not get on with BASIC...Of course the clever one would be to learn both :)

 

A simple bit of basic with embedded ML data, the flexibility of BASIC with the speed of ML..

It wouldn't be standard Atari Basic I'll use or learn, of course, it will be either Turbo BASIC or BASIC XL/XE. But I know knowing machine language is better, if for nothing else, to have the understanding of and most use for books like Mapping The Atari. The language on the Atari that actually excites me the most, is Action! So I will probably learn machine language and Action! in parallel. But I'm just thinking that possibly I need to learn BASIC first, due to simplicity compared to the others, a stepping stone to dip my toes in the programming water with. So it's a bit of a conundrum. I may just end up looking into Action! first, because it excites me so, being a unique to Atari 8-bits, and powerful high-level language, and therefore it may give me the ambition to see it through. I guess it will come down to whether I find Action! or a BASIC more preferable to start with in ease of learning.

Edited by Gunstar
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I may just end up looking into Action! first, because it excites me so, being a unique to Atari 8-bits, and powerful high-level language, and therefore it may give me the ambition to see it through. I guess it will come down to whether I find Action! or a BASIC more preferable to start with in ease of learning.

 

 

BASIC is more forgiving than Action! which does not check Array indices and will allow you to write everywhere in memory space if you get an array index wrong. There's a lot more literature about learning BASIC than there is for Action!, unfortunately. A beginner's guide to learn programming in Action! is sadly missing on the otherwise very well stocked Atari bookshelf. String handling is easier in BASIC but everything related to interfacing with the hardware is much easier as you can assign variables to hardware registers or their shadows and read and write them without using PEEKs and POKEs. If you try out Action!, there's a great collection of articles, tutorials, type-in-programs, etc. at AtariWiki.

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Of the top of my head, two more errors in Mapping:

 

* Appendix Fourteen, Cartridge connector H is A8 (not A9)

* $D300 (PORTA) has Jack 0 written were it should say Jack 2

 

Edit: which reminds me of,

 

There are two types of people:

1. Those that start counting at 1.

1. Those that start counting at 0.

 

Not sure where I got this ;)

 

And of course, there are 10 types of people. Those that know binary, and those that don't.

Edited by ivop
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Of the top of my head, two more errors in Mapping:

 

* Appendix Fourteen, Cartridge connector H is A8 (not A9)

* $D300 (PORTA) has Jack 0 written were it should say Jack 2

 

Edit: which reminds me of,

 

There are two types of people:

1. Those that start counting at 1.

1. Those that start counting at 0.

 

Not sure where I got this ;)

 

And of course, there are 10 types of people. Those that know binary, and those that don't.

Thanks, noted.

 

The people that start counting at 1 tend to count down to 0, So does that mean people that start counting at 0 only count down to 1? ;)

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