[haiku-development] Re: Haiku SSE status?

  • From: Alexander von Gluck <kallisti5@xxxxxxxxxxx>
  • To: <haiku-development@xxxxxxxxxxxxx>
  • Date: Fri, 20 Jan 2012 12:15:27 -0600

On 20.01.2012 12:00, Alexander von Gluck wrote:

On 20.01.2012 00:18, Fredrik Holmqvist wrote:

2012/1/20 Ingo Weinhold <ingo_weinhold@xxxxxx>:

Alexander von Gluck wrote:

On 19.01.2012 17:26, Ingo Weinhold wrote:
> Alexander von Gluck wrote:
>> 1) You can download the following (simple) sse2 test c program:
>> http://pub.haikufire.com/sse.c
>>
>> 2) compile it via: gcc sse.c -msse2 -o sse
>>
>> 3) run it to have it crash as soon as it attempts the sse code.
>
> Like on executing the first SSE instruction? And how does it crash (which 
> exception)?

"General Protection Fault"
If it happens when executing the first SSE instruction, then it's very likely something that we're not setting up (correctly). A look at the IA-32 specs should help find out what our setup is missing yet. 

I have the same issue with MMX. I havn't used MMX much before so I
thought it was just me. I've tried w/o alignment, saving/restoring
fpu, emms, sfence and so on. But just doing a 'movd %eax, %mm0' hangs.
From the x86 docs i've read, fxsave has to be called before a task switch, and fxrstore has to be called after a task 
switch to keep the fpu in a valid state with sse
I see references to us calling fxsave in kernel/arch/x86/arch_thread.cpp on arch_thread_init, however no calls to 
fxrstore.
nevermind.. the i386_fxsave_swap asm function actually does a fxsave and fxrstore
sorry for the spam.. getting close to just disabling sse instructions in Mesa until I can figure it out. 

 -- Alex

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