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update README with better overlay details

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Joshua Bell 2018-11-23 19:41:53 -08:00
parent f8d5358a88
commit 03929d70fd
1 changed files with 44 additions and 14 deletions
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desktop/README.md
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@ -125,9 +125,49 @@ as windows are opened and closed.
Interactive commands including disk copy/format/erase, file
copy/delete, and Selector add/edit/delete/run all dynamically load
main memory code overlays into one or more of: $800-$1BFF,
$5000-$6FFF, $7000-$77FF, and $9000-$9FFF. When complete, any original
code above $4000 is reloaded.
main memory code overlays. When complete, any original code above
$4000 is reloaded (unless a full restart is required.)
Several of the overlays also use a common file selector dialog overlay
`ovl4.s` ($5000-$6FFF).
#### Disk Copy Overlay
The Disk Copy command replaces large chunks of memory and is best
thought of as a separate application.
The first part (`ovl1.s`, $800-$9FF) loads into main memory the other
overlays, but in turn it loads a second short ($200-byte) overlay
(`ovl1a.s`, $1800-$19FF). This then loads a replacement for the
resources in the aux language card area (`ovl1b.s`, Aux LC
$D000-$F1FF) and another block of code in main memory (`ovl1c.s`, Main
$0800-$12FF). When exiting, the DeskTop is restarted from the
beginning.
#### Disk Format/Disk Erase
Simple overlay: `ovl2.s`, loaded into Main A$0800-$1BFF.
#### Selector - Delete Entry / Run Entry
Simple overlay: `ovl3.s` ($9000-$9FFF).
#### Selector - Add Entry / Edit Entry
Also uses `ovl3.s` ($9000-$9FFF) but additionally uses overlay
`ovl7.s` ($7000-$77FF) and the file selector dialog `ovl4.s`
($5000-$6FFF).
#### File Copy
Overlay `ovl5.s` ($7000-$77FF), uses file selector dialog `ovl4.s`
($5000-$6FFF).
#### File Delete
Overlay `ovl6.s` ($7000-$77FF), uses file selector dialog `ovl4.s`
($5000-$6FFF).
## Memory Map
@ -212,14 +252,4 @@ $0100 +-------------+ +-------------+
$0000 +-------------+ +-------------+
```
#### Disk Copy Overlay
The Disk Copy command replaces large chunks of memory and is best
thought of as a separate application.
The first part (`ovl1.s`) loads into main memory the other overlays,
but in turn it loads a second short ($200-byte) overlay (`ovl1a.s`).
This then loads a replacement for the resources in the aux language
card area (`ovl1b.s`) and another block of code in main memory
(`ovl1c.s`). When exiting, the DeskTop is restarted from the
beginning.
Memory use by the Disk Copy overlay is not shown.