From: Zhang Fuxin <fxzhang@ict.ac.cn>
To: "linux-mips@oss.sgi.com" <linux-mips@oss.sgi.com>
Subject: used_math not cleared for new processes?
Date: Sat, 2 Feb 2002 14:20:6 +0800 [thread overview]
Message-ID: <200202020723.g127N4d30447@oss.sgi.com> (raw)
hi,linux-mips,
I find that current->used_math isn't cleared when we start a new process.Is it
intended? I mean 'start_thread' in do_exec but not 'copy_thread' in do_fork when
speaking 'start a new process'. We can/should? keep used_math for the latter,but for
the former?
It leads to a failure in libm-test(the fpu control register doesn't equal to default)
I think the reason is that init_fpu fail to be called with used_math set.
BTW: besides this failure,i see a lot of more related to extra "Invalid operation" exception.
e.g.:
exp(NaN) == NaN: Exception "Invalid operation" set
fmax (0, NaN) == 0: Exception "Invalid operation" set
..
My cpu is IDT RC64474,which is basically a r4600.
I think the cause probably is mips's special SNaN and QNaN handling.
Could somebody explain?
Regards
Zhang Fuxin
fxzhang@ict.ac.cn
next reply other threads:[~2002-02-02 7:23 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-02-02 6:20 Zhang Fuxin [this message]
2002-02-27 22:53 ` used_math not cleared for new processes? Jun Sun
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