Re: [hatari-devel] DSP and HREQ

[Douglas Little <doug694@xxxxxxxxxxxxxx>]

Hi Laurent,

Yes it would be interesting to look at the full test.

The ISR probably does need cleared manually although I would expect the opposite effect - interrupts halting when they should resume on subsequent events.

D

On 16 February 2015 at 22:45, Laurent Sallafranque <laurent.sallafranque@xxxxxxx> wrote:

Hi nicolas,

I've found some time working on the test, and I get strange results :

The code of the exception :

dsp_inter:
    ; Read ISR
    clr.l        d0
    clr.l        d1
    clr.l        d2

    move.b        $ffffa202.w,d0
    move.b        $ffffa207.w,d1
    move.b        $ffffa202.w,d2

    ; Display Result (move result into D0 first)
    lea    TextNbBytes(pc),a0
    jsr    PrintHexLong

    pea     Begin_Text
    move.w  #9,-(sp)
    trap    #1
    addq.l  #6,sp

     ; Display Result (move result into D0 first)
    move.l    d1,d0
    lea    TextNbBytes(pc),a0
    jsr    PrintHexLong

    pea     Begin_Text
    move.w  #9,-(sp)
    trap    #1
    addq.l  #6,sp

     ; Display Result (move result into D0 first)
    move.l    d2,d0
    lea    TextNbBytes(pc),a0
    jsr    PrintHexLong

    pea     Begin_Text
    move.w  #9,-(sp)
    trap    #1
    addq.l  #6,sp

    rte


So, I read ISR, then a value sent from the DSP, then ISR again.

under hatari, I get :

ISR = $87
DSP = $3
ISR = $86

Then, There's no more interrupt and I can press space and quit.


Under my real Falcon, the behaviour is different : the interrupt is called forever (I never return to the main program to press space, as soon as the exception is over, there's another one that starts.
I can't read the 3 values, it scrolls too fast.

I haven't done the second test for now, but at least, the 1st one shows a big difference between hatari and real hardware.

I think I read somewhere that one has to reset ISR himself by software in the interrupted exception code to disable another exception, I'll read again the Motorola doc to find this.

I can send the full code of my test if someone is interrested.

Laurent




Le 26/01/2015 15:49, Nicolas Pomarède a écrit :

Hello

while looking at the level 6 interrupt ttat the DSP can trigger, I wonder if everything is emulated.