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Revs on the BBC Micro

Screen mode: paletteSection2

Name: paletteSection2 [Show more] Type: Variable Category: Screen mode Summary: Colour palette for screen section 2 in the custom screen mode (part of the mode 5 portion) Deep dive: Hidden secrets of the custom screen mode
Context: See this variable in context in the source code References: This variable is used as follows: * ScreenHandler calls paletteSection2

Palette data is given as a set of bytes, with each byte mapping a logical colour to a physical one. In each byte, the logical colour is given in bits 4-7 and the physical colour in bits 0-3. See p.379 of the Advanced User Guide for details of how palette mapping works, as in modes 4 and 5 we have to do multiple palette commands to change the colours correctly, and the physical colour value is EOR'd with 7, just to make things even more confusing. Each of these mappings requires six calls to SHEILA &21 - see p.379 of the Advanced User Guide for an explanation.
.paletteSection2 EQUB &07, &17 \ Map logical colour 0 to physical colour 0 (black) EQUB &47, &57 EQUB &23, &33 \ Map logical colour 1 to physical colour 4 (blue) EQUB &63, &73 EQUB &80, &90 \ Map logical colour 2 to physical colour 7 (white) EQUB &C0, &D0 EQUB &A5, &B5 \ Map logical colour 3 to physical colour 2 (green) EQUB &E5, &F5