OS_SpriteOp 37 (changes)
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Programmer's OS Reference SWI Manuals Calls
» Part OS_SpriteOp 15 – SWI Calls
» OS_SpriteOp 37 – Create/remove PaletteOS
» OS_SpriteOp
» OS_SpriteOp 37 – Create/remove Palette
OS_SpriteOp 37 – Create/remove Palette
(SWI &2E)
| Entry | |
|---|---|
| R0 | 37 (Reason code) + Area value |
| R1 | Unused/Sprite area (as defined by area value in R0) |
| R2 | Sprite name/pointer (as defined by area value in R0) |
| R3 | Mode: |
| -1 → Read palette size | |
| 0 → Remove palette | |
| Otherwise → Create palette | |
| → If bit 31 set, create full 256 entry palette |
| Exit | |
|---|---|
| If R3 = -1 on entry: | |
| R3 | Size of palette (bytes), 0 if none |
| R4 | Pointer to palette, or 0 if none |
| R5 | Sprite Mode Word |
| All other registers preserved | |
Use
This call allows a palette to be added or removed from a sprite, or for the size and location of a palette to be read.
For 256 colour sprites, bit 31 of R3 controls whether a 64 or 256 entry palette is created. For other colour depths this bit is ignored.
Notes
If an attempt is made to add a palette to a true-colour sprite, an error will be returned.
Because sprite palettes contain 8 bytes per entry, when reading the size/location of a palette using R3=-1 the number of palette entries is actually the returned R3 value divided by eight.
See also
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