Subject: Re: regress/lib/libc/ieeefp/except
To: None <>
From: Toru Nishimura <>
List: port-mips
Date: 06/01/2000 16:01:04
Mystery deepens.

I wrote as follows last month;

> I got a kernel panic when tried regress/lib/libc/ieeefp/except/except
> program with my personal DECstation which supposedly has R3000A
> (single chip with combined FPA) inside.  Message was 'kernel touched
> FPA' and faulting address did not make sense (around ast() address).

Now I can reproduce the same situation in other ways with the most
recent kernels.  R3000 processor posts INT5 interrupt requesting the
intervension of kernel emulation for FP insn(s).  EPC always points
the 2nd insn of ast() routine which does not make sense to me.  I'm
confused about what't the exact condition(s) produces FP interrupt on
R3000.  A possible cause would be a glitch in fp.S which will
repeatedly generate (it's what I'm watching) INT5 interrupts once it
dives into an infinite loop.  Can someone out there throw a towel to

Tohru Nishimura