From: Al Viro <viro@ZenIV.linux.org.uk>
To: Richard Henderson <rth@twiddle.net>
Cc: Peter Maydell <peter.maydell@linaro.org>,
QEMU Developers <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] [RFC] alpha qemu arithmetic exceptions
Date: Thu, 3 Jul 2014 19:25:01 +0100 [thread overview]
Message-ID: <20140703182501.GQ18016@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20140703065104.GP18016@ZenIV.linux.org.uk>
On Thu, Jul 03, 2014 at 07:51:04AM +0100, Al Viro wrote:
> FWIW, why not just generate
> trunc_i64_i32 tmp, va
> trunc_i64_i32 tmp2, vb
> muls2_i32 tmp2, tmp, tmp, tmp2
> ext32s_i64 vc, tmp2
> maybe_overflow_32 tmp
> where maybe_overflow throws IOV unless tmp is 0 or -1?
> to suffice for mull/v. mulq/v would be
> muls2_i64 vc, tmp, va, vb
> maybe_overflow_64 tmp
> addl/v:
> trunc_i64_i32 tmp, va
> trunc_i64_i32 tmp2, vb
> add2_i32 tmp2, tmp, tmp, zero, tmp2, zero
> ext32s_i64 vc, tmp2
> maybe_overflow_32 tmp
> etc.
Grr... Wrong check, obviously - we want to check that tmp + MSB(tmp2) is 0.
Something like
setcond_32 tmp2, tmp2, zero, TCG_COND_LT
add_i32 tmp, tmp2, tmp
call helper_IOV_if_not_zero tmp
for 32bit ones and
setcond_64 tmp2, vc, zero, TCG_COND_LT
add_i64 tmp, tmp2, tmp
call helper_IOV_if_not_zero tmp
for 64bit ones, or would it be better just to pass both arguments to helper
and let it deal with the check? I'm not familiar enough with TCG, sorry...
next prev parent reply other threads:[~2014-07-03 18:25 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-24 4:34 [Qemu-devel] [RFC] alpha qemu arithmetic exceptions Al Viro
2014-06-24 16:52 ` Al Viro
2014-06-24 18:33 ` Richard Henderson
2014-06-24 20:32 ` Al Viro
2014-06-24 20:57 ` Richard Henderson
2014-06-24 21:24 ` Al Viro
2014-06-24 21:32 ` Richard Henderson
2014-06-25 7:01 ` Al Viro
2014-06-25 9:27 ` Peter Maydell
2014-06-25 14:26 ` Al Viro
2014-06-25 17:41 ` Peter Maydell
2014-06-26 5:55 ` Al Viro
2014-06-30 18:39 ` Richard Henderson
2014-06-30 20:56 ` Al Viro
2014-07-01 4:34 ` Al Viro
2014-07-01 5:00 ` Al Viro
2014-07-01 14:31 ` Richard Henderson
2014-07-01 17:03 ` Richard Henderson
2014-07-01 17:50 ` Al Viro
2014-07-01 18:23 ` Peter Maydell
2014-07-01 18:30 ` Richard Henderson
2014-07-01 19:08 ` Peter Maydell
2014-07-02 4:05 ` Al Viro
2014-07-02 5:50 ` Al Viro
2014-07-02 6:17 ` Al Viro
2014-07-02 15:26 ` Richard Henderson
2014-07-02 15:49 ` Al Viro
2014-07-02 14:59 ` Richard Henderson
2014-07-02 15:20 ` Al Viro
2014-07-03 6:51 ` Al Viro
2014-07-03 18:25 ` Al Viro [this message]
2014-07-03 20:19 ` Richard Henderson
2014-07-03 22:47 ` Al Viro
2014-07-03 23:05 ` Peter Maydell
2014-07-03 23:22 ` Al Viro
2014-07-04 0:50 ` Al Viro
2014-07-04 4:30 ` Richard Henderson
2014-07-04 7:29 ` Al Viro
2014-07-05 1:40 ` Al Viro
2014-07-05 5:26 ` Al Viro
2014-07-05 21:09 ` Al Viro
2014-07-05 22:55 ` Al Viro
2014-07-07 14:11 ` Richard Henderson
2014-07-07 15:06 ` Al Viro
2014-07-07 16:20 ` Richard Henderson
2014-07-08 4:20 ` Al Viro
2014-07-08 6:03 ` Richard Henderson
2014-07-08 6:54 ` Al Viro
2014-07-08 7:13 ` Al Viro
2014-07-08 8:05 ` Peter Maydell
2014-07-08 14:53 ` Richard Henderson
2014-07-08 16:13 ` Al Viro
2014-07-08 16:33 ` Peter Maydell
2014-07-08 17:20 ` Al Viro
2014-07-08 19:32 ` Peter Maydell
2014-07-08 20:12 ` Al Viro
2014-07-09 9:19 ` Alex Bennée
2014-07-09 9:04 ` Alex Bennée
2014-07-08 18:12 ` Richard Henderson
2014-07-08 19:02 ` Al Viro
2014-07-08 19:04 ` Richard Henderson
2014-07-08 20:20 ` Al Viro
2014-07-09 4:59 ` Richard Henderson
2014-07-09 5:47 ` Al Viro
2014-07-09 15:14 ` Richard Henderson
2014-07-09 16:41 ` Al Viro
2014-06-24 18:23 ` Richard Henderson
2014-06-24 20:47 ` Al Viro
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