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Atari coding BBS
Re: Overscan+rasters
Posted by: leonard May,02.2017-14:29 

Does the MPP picture format by sector one already handle all these stuff? ( many colors + fullscreen )
If you are STE specific you could even use blitter to change colors. I guess MPP already support that.

SID voice is more tricky. I use it in one fullscreen in the 20th birthday reset demo. I use a 15Khz replay (one sample per scanline), using a 16bit fractional int to handle the SID phase. the code looks like:

add.w a0,d0 ;sid phase inc
bcc.s .skip
swap d0
.skip: move.b d0,(a1) ; a1 is YM register, and d0 contains 0 and SID volume level

the trick is that the routine takes exactly the same time, whatever the BCC branch or not, because of the SWAP dn" taking 4 cycles

[All messages in this thread]

Topic Posted by  Date 
Overscan+rasters mic/dune May,02.2017-12:38
  Re: Overscan+rasters leonard May,02.2017-14:29
    Re: Overscan+rasters mic/dune May,02.2017-23:39
      Re: Overscan+rasters ggn May,03.2017-08:20
        Re: Overscan+rasters dml May,03.2017-12:22
          Re: Overscan+rasters Troed May,26.2017-07:48
      Re: Overscan+rasters mic/dune May,03.2017-18:25
        Re: Overscan+rasters leonard May,03.2017-22:49
          Re: Overscan+rasters mic/dune May,04.2017-07:44
          Re: Overscan+rasters evil May,05.2017-20:26
            Re: Overscan+rasters mic/dune May,05.2017-22:54

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