[hatari-devel] Bus Error fault address in 24-bit

[Vincent Rivière <vincent.riviere@xxxxxxxxxxx>]

Hello.

See the attached source and binary. It willingly causes a Bus Error by doing 
"tst.w $ffffddee.w". If you run it with EmuTOS, you will see a nice register 
dump instead of 2 bombs. That information comes from the exception stack frame.

However, there is something suspicious when I run it with Hatari and ST 
Mode. EmuTOS prints that message on the screen:

Panic: Bus Error
misc=4a71 opcode=4a78
addr=00ffddee sr=0300 pc=0001d330

Look at addr=. It is the fault address. The high byte is 0. I would have 
expected it was ff, as it is specified in the source.

I suspect it is a Hatari bug in 24-bit address mode. It should be checked on 
real hardware, but unfortunately I have none right now.

One way to test is to use the EmuTOS floppy as OS:
- run buserr.tos
- see the panic message.

Other solution is to use stock TOS ROM:
- run buserr.tos: it displays 2 bombs and quickly exit
- run SYSINFO.PRG, type F7 for "Crash info"
- see the second and third words on the stack to see the fault address

--
Vincent Rivière

	tst.w	$ffffddee.w

Attachment: buserr.tos
Description: Binary data