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From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc
Date: Mon, 10 Apr 2006 19:13:54 +0100	[thread overview]
Message-ID: <200604101913.56210.paul@codesourcery.com> (raw)
In-Reply-To: <BAY104-F23360ECDB73F3CB2DDA7D2FFCC0@phx.gbl>

On Monday 10 April 2006 19:04, Blue Swirl wrote:
> >Doesn't this condition in addx and the corresponding line in subx need
> >similar
> >treatment?
>
> They don't change the flags.

It certainly look like they do.

In particular if TARGET_SPARC64 we have

    if ((T0 & 0xffffffff) < (src1 & 0xffffffff))
        env->psr |= PSR_CARRY;

But if !TARGET_SPARC64 we have

-    if (T0 < src1)
+    if (T0 < src1 || (has_carry && T0 <= src1))
 	env->psr |= PSR_CARRY;

I'd expect these two to be the same (modulo the explicit truncation in the 
first case).

Paul

  reply	other threads:[~2006-04-10 18:14 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-04-08 13:46 [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxcc and subxcc ops Even Rouault
2006-04-09 20:38 ` Paul Brook
2006-04-10 18:04   ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update inaddxcc and subxc Blue Swirl
2006-04-10 18:13     ` Paul Brook [this message]
2006-04-10 18:46     ` Laurent Desnogues
2006-04-10 20:18       ` Even Rouault
2006-04-10 17:57 ` [Qemu-devel] [PATCH] SPARC target : Fix carry flag update in addxccand subxc Blue Swirl

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