From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Larmour To: bartv@cygnus.co.uk Cc: ecos-discuss@sourceware.cygnus.com Subject: [ECOS] Re: Ecos Port to PPC509/PPC555 Date: Tue, 28 Sep 1999 08:02:00 -0000 Message-id: <37F0D88A.EF0DCD5E@cygnus.co.uk> References: <37E80554.7D56118D@danlawinc.com> <199909231448.PAA13861@sheesh.cygnus.co.uk> <87puz8v8sh.fsf@osv.javad.ru> <199909271854.TAA26830@sheesh.cygnus.co.uk> <37F00D1F.FDEC9E27@cygnus.co.uk> <199909281459.PAA09627@sheesh.cygnus.co.uk> X-SW-Source: 1999-09/msg00049.html Bart Veer wrote: > > >>>>> "Jifl" == Jonathan Larmour writes: > Jifl> But you can't rely on FP exceptions being generated - they > Jifl> don't for normal code, so I don't believe this is a viable > Jifl> option unless I've misunderstood you. > > On some architectures including the PPC (if I remember correctly), it > is possible to disable the floating point unit. The first operation > that attempts to access the floating point unit, even if it is just to > access a floating point register, will cause a hardware exception. > This is separate from normal floating point exceptions such as > overflow. Oops yes. I did misunderstand you :-). For what its worth, MIPS and x86 have this as well IIRC. Jifl -- Cygnus Solutions, 35 Cambridge Place, Cambridge, UK. Tel: +44 (1223) 728762 "I used to have an open mind but || Get yer free open source RTOS's here... my brains kept falling out." || http://sourceware.cygnus.com/ecos Help fight spam! http://spam.abuse.net/ These opinions are all my own fault