====== Palette ======

The integrated palette contains 256 color entries. VGA ports and native I/O aliases address the same programming interface.

^ Operation ^ VGA port ^ Native I/O ^
| Write index | ''0x3C8'' | ''+0xB0'' |
| Data | ''0x3C9'' | ''+0xB1'' |
| Pixel mask | ''0x3C6'' | ''+0xB2'' |
| Read index | Write ''0x3C7'' | ''+0xB3'' |
| DACState | Read ''0x3C7'' | — |

Byte data accesses sequence through red, green and blue. A palette word write supplies red in bits 23:16, green in 15:8 and blue in 7:0, then increments to the next color triple. This permits 256 word writes for a full palette. Reads still use bytes.

Command0 selects six- or eight-bit palette output and power-down. Command1 selects 8/16/32-bit pixel mode and palette bypass. Command2 selects cursor mode and contiguous or sparse palette indexing. Cursor colors have their own read/write index and data ports.

The catalogue's palette entry diagrams describe these RGB component programming values. They do not establish the physical width of the internal palette RAM.

At I/O +0xBA, Table 7a describes Command4/signature analysis, while Table 7b describes Palette Status with different fields. The detailed Status table is used for the diagram; the conflicting description remains visible in [[reference:source_issues|PALETTE_BA]].

[[registers:palette-ram:start|All 256 palette entries]] · [[registers:host-registers:palette_word_write|RGB word-write format]] · [[video:cursor|Cursor]]

Sources: [[https://verite.3d32.org/_media/source/v2200spec.pdf#page=51|Technical Spec, p.51]], [[https://verite.3d32.org/_media/source/v2200spec.pdf#page=52|Technical Spec, p.52]]