Re: [hatari-devel] DSP for Previous

[Andreas Grabher <andreas.grabher@xxxxxxxxxxxx>]

Luckily it turned out that the mode bits in the system control register are inverted. So mode 2 is mode 1 and that is the one that is implemented.

With some additions to the code (some bits in ICR seemed to be ignored) now at least it does something.

Maybe some of these changes are useful for Hatari too (see appended file). I'd be glad if someone could check them for correctness.

btw. It seems to me that Hatari is releasing the HREQ interrupt in a wrong way. DSP should release it, not CPU.

Attachment: dsp_patch3.diff
Description: Binary data

Am 03.06.2015 um 19:10 schrieb Douglas Little <doug694@xxxxxxxxxxxxxx>:

Hi,

I added the DSP code from Hatari v1.8.0. It was easy to make it compile. But then i ran into an early problem:

The 56001 has 4 operating modes:

Has anyone some insight in how the other modes could be implemented? At first look the differences between the modes seem to be mostly related to DSP reset.

IIRC the modes affect two things - the reset 'delay' (16 cycles vs 'lots') and the address of external memory to bootstrap from. However, I haven't used any of that so there may be further complications :)

D