Re: [hatari-devel] DSP for Previous

Thank you Miro, Laurent and Eero for your answers. I'm glad to hear that the DSP is quite complete. So it is worth a try to add it to Previous.

For the memory mapping:

I don't know the exact mapping. But the NeXT systems have built-on 24 kB of external DSP SRAM, that was expandable to 96 kB (in fact the expansion module has 96 K; if installed, the built-in 24 K are no longer accessible).

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:

0 --> single-chip mode

1 --> special bootstrap mode

2 --> normal expanded mode

3 --> development mode

Looking at the existing emulation code it seems to be the only mode implemented is mode 1. Is that correct or am i missing something?

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.

Am 02.06.2015 um 18:21 schrieb Miro Kropáček <miro.kropacek@xxxxxxxxx>:

On Tue, Jun 2, 2015 at 6:07 PM, Andreas Grabher <andreas.grabher@xxxxxxxxxxxx> wrote:
Do you think it can be interfaced with the NeXT stuff?

I'll let the technical questions to be answered by the Hatari team but it definitely can by interfaced. Some years ago I took its DSP sources and integrated it into my DSP simulator: https://github.com/mikrosk/cute56 ... easy peasy.

The level of emulation precision is excellent (even for such aged source!), the main source of problems in Hatari comes from CPU <-> DSP sync.

--
MiKRO / Mystic Bytes
http://mikro.atari.org