Re: TSCs are a no-no on i386

[Jan-Benedict Glaw <jbglaw@lug-owl.de>]

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On Wed, 2003-07-30 20:45:29 +0200, Adrian Bunk <bunk@fs.tum.de>
wrote in message <20030730184529.GE21734@fs.tum.de>:
> On Wed, Jul 30, 2003 at 11:30:33AM -0700, Mike Fedyk wrote:
> > On Wed, Jul 30, 2003 at 08:10:06PM +0200, Adrian Bunk wrote:
> > > On Wed, Jul 30, 2003 at 03:56:23PM +0200, Jan-Benedict Glaw wrote:
> > > > Please apply. Worst to say, even Debian seems to start using i486+
> > > > features (ie. libstdc++5 is SIGILLed on Am386 because there's no
> > > > "lock" insn available)...
> > > 
> > > Shouldn't the 486 emulation in the latest 386 kernel images in Debian
> > > unstable take care of this?
> > 
> > What emulation?
> 
> 486 emulation
> CONFIG_CPU_EMU486
>   When used on a 386, Linux can emulate 3 instructions from the 486 set.
>   This allows user space programs compiled for 486 to run on a 386
>   without crashing with a SIGILL. As any emulation, performance will be
>  very low, but since these instruction are not often used, this might
>   not hurt.  The emulated instructions are:
>      - bswap (does the same as htonl())
>      - cmpxchg (used in multi-threading, mutex locking)
>      - xadd (rarely used)

libstdc++ (and it's main user, apt-get) break at a LOCK insn.

MfG, JBG

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   Jan-Benedict Glaw       jbglaw@lug-owl.de    . +49-172-7608481
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