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List:       netbsd-port-i386
Subject:    Re: NetBSD-9 on 80486?
From:       Rin Okuyama <rokuyama.rk () gmail ! com>
Date:       2021-07-30 2:49:05
Message-ID: 31610bc3-0ac4-1047-31d1-872a3851d68d () gmail ! com
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On 2021/07/30 11:21, John Klos wrote:
> Hi,
> 
> > NetBSD requires 486 instructions *and* x87 FPU; MATH_EMULATE option
> > was removed back in 2008 before 5.0 was released:
> > 
> > http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/arch/i386/i386/Attic/math_emulate.c?hideattic=0
> >  
> > According to Wikipedia, Cx486DLC lacks internal FPU. This should be
> > why it does not work. Does the system have slot for external FPU?
> 
> The board has an FPU installed (ULSI "DX/DLC"), and even though the dmesg doesn't \
> show it, NetBSD makes use of it as evidenced by pkgsrc/benchmarks/flops, plus \
> sysctl gives machdep.fpu_present = 1. 
> Hmmm...

Hmm, NetBSD 5.0 is the first release after i386 support was removed:

http://gnats.netbsd.org/36163

Cx486DLC may not fully support i486 instructions. Linux seems to drop
its support along with i386:

https://lkml.org/lkml/2012/12/11/131

Thanks,
rin


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