Re: [hatari-devel] TT palette bankswitching should be supported

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

Bank number is taken into account in the ST & TT color register writes.

	- Eero

On 02/19/2016 08:05 PM, Roger Burrows wrote:
> When running in ST Low, ST medium, or TT medium, the TT video hardware supports
> bankswitching for the palette: the part of the TT palette that maps to the
> STe-compaitble palette can be changed, by changing the "bank number" in the TT
> shifter.
>
> After power-on reset, the bank number is the set to zero, which causes the
> first 16 TT palette registers to map to the STe palette registers.  If you set
> the bank number to N, then TT palette registers 16*N to 16*N+15 are mapped
> instead.  There is even a special TOS3 XBIOS call, EsetBank(), to do this.
>
> Hatari does not support this.
>
> In video.c, function Video_TTShiftMode_WriteWord(), I think that there needs to
> be a check for bank number, which would then be used (I don't want to guess
> where) to do the mapping.
>
> Tested on a real TT, and documented in "Atari TT030 Hardware Reference Manual".
>
> Roger