Re: [hatari-devel] DSP endless loop

Am 06.05.2017 um 03:13 schrieb Douglas Little <doug694@xxxxxxxxxxxxxx>:

Hi,

I have a appended disassembly output from a DSP program that seems to go to an endless loop, which freezes the whole operating system. It is a long time ago i last debugged the DSP. Maybe someone with more experience sees the problem. If the problem is within DSP emulation it potentially affects Hatari too.

Are you sure it's going into an endless loop? The trace shows the program transfers a bunch of data/code and then goes into a polling loop waiting for something else to do. It's late to debug this properly - but it doesn't look like its necessarily broken (on the DSP side anyway).

Your suspicion was right. Obviously i was not waiting long enough (things are really slow in trace mode). It continues and then goes to another loop, which is much more complex. If it is not a DSP problem it might be a problem on the host side (probably a timing problem?). I appended another trace output. But i'm not sure it is useful.

However you might want to make sure the DO loops are correct. I spotted some flow control instructions (jmp/jsr etc) near DO labels and this isn't allowed for those kinds of instructions - undefined behaviour. Put some nops before/after the do labels to test that.

Other than doubts about the DO loops it's probably the host program losing sync, not handshaking properly or just sending the wrong data.

D.