Clip Window Control Register

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Number $1C
Readable Yes
Writable Yes
Short Description Controls (resets) the clip-window registers indices.

Write:

Bit Function
7-4 Reserved, must be 0
3 reset the Tilemap clip-window register index (by writing 1).
2 reset the ULA/LoRes clip-window register index (by writing 1).
1 reset the Sprite clip-window register index (by writing 1).
0 reset the Layer 2 clip-window register index (by writing 1).

Read:

Bit Function
7-6 the current Tilemap clip-window register index
5-4 the current Layer 2 clip-window register index
3-2 the current Sprite clip-window register index
1-0 the current ULA/LoRes clip-window register index

Each read index maps as 0: X1, 1: X2, 2: Y1 and 3: Y2 (the same order how the coordinates are written to particular clip-window register).