Re: brokenlc040 and FPU-less plans?

On Monday, Mar 29, 2004, at 13:00 US/Pacific, Riccardo Mottola wrote:

> I think there is no easy hope to have borken LC's CPU to work. Neither
> NetBSD nor Linux can and it wouldn't really make much sesne.
> The best method would do to make a distribution compiled without FPU
> instructions and then take care to compile the rest w/o them. This is
> what NetBSD did.
>
> To have 030 and "sane" LC040 (if they exist) work we need FPU  
> emulation.
> I don't know if that is currently working in OpenBSD.
> NetBSD and LInux have 'provisions' for that but not all instructions
> areimplemented yet, even if there was progress.

I hope those trying to address the LC040 FPU problem are aware of the  
mask bug in some 68LC040 CPU's...

<http://lists.debian.org/debian-68k/2000/debian-68k-200008/ 
msg00076.html>:

[My note:  Is 68EC040 a typo?  Do they really mean 68LC040?  I suspect  
one should read it assuming so.]

         - MC68EC040 processors with mask 02E23G does not handle FPU
           instructions correctly. This failure occurs if a write
           instruction is followed immediatly by a FPU instruction.
           The CPU does not generate a correct FLINE exception and so
           the FPU emulation will not work.
           This bug will be fixed in mask 02E71.

         5.1 Workarounds for MC68EC040 FPU problem

         - Insertion of a NOP before the FPU instruction solves the
           problem.
         - Using an adequate compiler option preventing the generation
           of FPU instructions solves the problem.
         - Code generated by the ULTRA C Compiler (UCC) version 1.0 does
           not run on the MC68EC040. This is due to a FMOVEM instruction
           generated by the compiler for any function call.
         - The UCC version 1.1, 1.2 and the GNU-Compiler generate FPU
           instructions only if float functions are used. So some  
problems
           may be fixed using a newer UCC version.

           The problems described in this paragraph are independent of  
the
           OS9 version used on the system.
           Microware Utilities compiled with the UCC on OS9-V3.0 may  
possibly
           contain FPU instructions. So the ftp utility seems to have  
this
           problem. There are no further problems known with other  
utilities
           at this time.
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