[hatari-devel] Suspected Hatari 2.3.0 regression (prefetch?)

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Hi!
I'm working on an incompatibility (reported by Eero) between EmuTOS and TOS4 
when running a program called DELMPAINT.  I have previously been using Hatari 
2.2.1 to help debug this.

I just switched to 2.3.0, and DELMPAINT now gets a bus error doing something 
that it did before without crashing, when run with Hatari 2.2.1.  The problem 
occurs when DELMPAINT tries to copy the Falcon palette registers at 
$ff9800-$ff9bff to its own memory.  It does it with a loop that copies 512 
bytes at a time.  The program initialises a0 to $ff9800, a1 to its own memory, 
then does the following loop twice:
    movem.l  (a0)+,d1-d7/a2            ; copy 32 bytes
    movem.l  d1-d7/a2,(a1)
    movem.l  (a0)+,d1-d7/a2-a6         ; copy 48 bytes
    movem.l  d1-d7/a2-a6,$20(a1)
    ...
    movem.l  (a0)+,d1-d7/a2-a6         ; copy 48 bytes
    movem.l  d1-d7/a2-a6,$1a0(a1)
    movem.l  (a0)+,d1-d7/a2-a6         ; copy 48 bytes ***
    movem.l  d1-d7/a2-a6,$1d0(a1)

The crash occurs in the second (and last) time through the loop, at the 
instruction marked with *** above.  After that instruction, a0 will point to 
$ff9c00 (although that address has not been read, at least from a programming 
POV).  The error msg from Hatari is "Bus Error reading at address $ffff9c00".

Roger
P.S. If you need DELMPAINT, Eero can point you to it.




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