Re: freezes when not emulating CPU (was: MIDI input patch)

[Stas Sergeev <stsp@aknet.ru>]

Hello.

Bart Oldeman wrote:
 > exception happens -- I guess that was just meant for debugging).
 > Thanks (to Stas also),
The "SB16 fixes from Stas Sergeev via x.zupftom@web.de on linux-msdos."
is actually also the related FPU fix.
There was a division by zero there in
pcm_samp_period() (when called without
the necessary checks), which I became
aware of, because it started to produce
SIGFPE when I played with vm86_fpu_state
struct. Which means that the comment in
do_vm86.c about fnsave is wrong, and the
code that restores the dosemu FPU state
should likely to be returned. You can,
for example, memset the vm86_fpu_state
to 0 in fpu_reset() and see the SIGFPE
coming from all around the sound code
(no other code use FPU in dosemu).
Also, I found no docs about this FPU
init/reset stuff, so everything in this
patch is just a wild guesses based on
a look into a bochs code.
Also, there is a need to add the handling
for exception 0x13 (SIMD FPE), which is
what the SIGFPE is about today. I mean,
at least print_exception_info() should
write something meaningfull about SIGFPE
instead of "Unknown exception".
So I guess this patch needs more work,
but it should be harmless in its current
form too.