Re: [hatari-devel] TOS 3.00

[Thorsten Otto <admin@xxxxxxxxxxx>]

On Samstag, 9. Februar 2019 00:31:53 CET Eero Tamminen wrote:

> I'm not getting TOS 3.00 to boot in Hatari TT emulation:

> http://www.atari-forum.com/viewtopic.php?f=27&t=35161

>

> It's just looping on some MFP register:

> $00e01ed4 : cmp.l $04ba.w,d7 24.95%

> $00e01ed8 : bcs.s $e01eea 24.95%

> $00e01eda : btst #5,$fffffa01.w 24.95%

> $00e01ee0 : bne.s $e01ed4 24.95%

 

Thats a bit strange, because almost the same sequence can be found in TOS 3.06:

 

[00e019ec] b0b8 04ba cmp.l $04ba.w,d0

[00e019f0] 650c bcs.s 00e019fe

[00e019f2] 0838 0005 fa01 btst #5,$FA01.w

[00e019f8] 66f2 bne.s $e019ec

 

It's purpose is to wait for a dma transfer to complete, with a timeout of either 3sec or 1/10 sec (the values are shortly before that sequence). Maybe something is going wrong with the 200hz timer?