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mg_notes:apple_iic:accelerator [2017/07/18 02:14] M.G. [MIG RAM Use] |
mg_notes:apple_iic:accelerator [2017/07/25 16:16] M.G. [MIG RAM Use] |
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| ==== MIG RAM Use ==== | ==== MIG RAM Use ==== | ||
| - | The stock firmware uses MIG RAM page 2 as follows: | + | The stock firmware uses [[mg_notes:apple_iic:mig_chip|MIG]] RAM page 2 as follows: |
| * $00 - powerup byte 1 - $33 after init. | * $00 - powerup byte 1 - $33 after init. | ||
| Line 15: | Line 15: | ||
| * $02,$03 - current accelerator control word. | * $02,$03 - current accelerator control word. | ||
| * $04 - keyboard keypress at RESET time, used to detect <key>ESC</key> during reset. | * $04 - keyboard keypress at RESET time, used to detect <key>ESC</key> during reset. | ||
| - | * $05-$08 - copies of what should be in Zip Chip $C05c-$c05f registers (respectively). | + | * $05-$08 - copies of what should be in Zip Chip $c05c-$c05f registers (respectively). |
| * $10-$17 - used to save zero page locations $00-$07. | * $10-$17 - used to save zero page locations $00-$07. | ||
| * Others - apparently unused. | * Others - apparently unused. | ||