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Atari System Reference Manual - Missing Text

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Carsten Strotmann

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Jan 3, 2006, 12:37:30 PM1/3/06
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There are multiple copies of the Atari System Reference Manual (Bob
DuHamel, 1987) around in the internet, and all have some text missing in
Chapter 15 Displaylist:

CHAPTER 15

DISPLAY LISTS


[some of this file was lost...]


chip also has a memory scan counter. This register scans the display
buffer for data to be interpreted and displayed. Once loaded, the
memory scan counter's 4 most significant bits are fixed. The result
is that the memory scan counter cannot cross a 4K memory boundary
(i.e. $AFFF to $B000) without being reloaded.

DISPLAY LIST INSTRUCTIONS

--------------

I have found the original text on some disks:

--------------

CHAPTER 15

DISPLAY LISTS

The program which runs the ANTIC chip is called the display list. Much
like a microprocessor, the ANTIC chip has a program counter, called the
display list counter.

The display list counter is a 16 bit register. However, the six most
significant bits are semi-fixed. These bits can only be changed with a
jump instruction. The result of this is that the display list counter
cannot cross a 1K memory boundary (i.e. $A3FF to $A400) without using a
jump instruction.

The ANTIC chip finds the address of the display list in DLISTL [$D402
(54274)] and DLISTH [$D403 (54275)]. SDLSTL [$0230 (560)] and SDLSTH
[$0231 (561)] are the shadow registers for DLISTL and DLISTH.

The ANTIC chip also has a memory scan counter. This register scans the
display buffer for data to be interpreted and displayed. Once loaded, the
memory scan counter's 4 most significant bits are fixed. The result is
that the memory scan counter cannot cross a 4K memory boundary (i.e. $AFFF
to $B000) without being reloaded.

--------------

If you host some version of this manual, please update you version ;)

Best regards

Carsten Strotmann

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