FreeBSD C lib : FPU usage

To: oskit users list <oskit-users@cs.utah.edu>
Subject: FreeBSD C lib : FPU usage
From: Yves Martin <ymartin@ensisun.imag.fr>
Date: Thu, 23 Mar 2000 11:23:20 +0100 (MET)
Sender: owner-oskit-users@fast.cs.utah.edu


	I'm using i386 task switching features
  with OSKit network devices, which need freebsd_c
  library.
  
  But something calls 'setjmp' and the freebsd_c
  'setjmp' uses this FPU instruction :
  - fnstcw
  and of course longjmp uses :
  - fninit, fldcw
  
  which raise the exception 7 Device Not Available #NM
  because TS flag in CR0 is set !
  
  Why ? because I use TRAP GATE in IRQ entries in IDT
  
  Why cannot I handle exception 7 to make save/restore
  FPU context and content to correct this ?
  Because my prog is supposed to debugged a kernel,
  which may also use TSS, with FPU and exception 7.
  
  Does anybody think about a possible solution
  to use OSKit devices without FPU instructions ?
  
 Regards.

-- Yves Martin --- Elève-ingénieur ENSIMAG - 3e année ---
  Adr : R.H.B. Ch. 765     Yves.Martin@ensimag.imag.fr   
  2 av. J. O.  GRENOBLE      Tél: 04 76 44 20 01         
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Re: FreeBSD C lib : FPU usage

From: Alastair Reid <reid@cs.utah.edu>