Re: [hatari-devel] Possible bug in 060 exception stack frames

[Thorsten Otto <admin@xxxxxxxxxxx>]

On Sonntag, 24. Januar 2021 20:17:43 CET Toni Wilen wrote:

> FScc, FDBcc and FTRAPcc does not modify FPIAR

 

Hm, are you sure about this? The manual states:

 

"For the subset of the FPU instructions that generate exception traps, the 32-bit FPIAR is loaded with the logical address of the instruction before the processor executes it."

 

And why are they zero now? Shouldn't that still be the address of the previous FPU instruction, like it was before your recent changes? Guess that has to verified on real hardware.

 

>Not sure why SNAN test does not work. Does it even cause an exception?

 

 

I addes a printf in fpsr_check_arithmetic_exception (the value is the FPSR). This is what i get with 060:

FPP exception: 02001048

FPP exception: 00000800

FPP exception: 09004080

FPP exception: 01002080

FPP exception: 02001048

FPP exception: 00000800

FPP exception: 02000410

FPP exception: 00000208

 

and with 040:

FPP exception: 01002080

FPP exception: 02001048

FPP exception: 00000800

FPP exception: 02000410

FPP exception: 00000208

 

So no, SNAN (mask 0x4000) does not seem to generate an exception.