From: malc <av1474@comtv.ru>
To: Matthew Ogilvie <mmogilvi_qemu@miniinfo.net>
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 2/3] target-i386/translate.c: mov to/from crN/drN: ignore mod bits
Date: Sat, 28 Jul 2012 00:53:33 +0400 (MSK) [thread overview]
Message-ID: <alpine.LNX.2.00.1207280051560.5057@linmac> (raw)
In-Reply-To: <1343415357-5637-3-git-send-email-mmogilvi_qemu@miniinfo.net>
On Fri, 27 Jul 2012, Matthew Ogilvie wrote:
> Microport UNIX System V/386 v 2.1 (ca 1987) uses mod R/M bytes for
> the control register mov instructions where the mod bits are 0,
> even though the 80386 spec claims they are "always" 1's. The fact
> that it ran at all clearly indicates the real chips (at least 386
> and 486) just ignores the bits and assumes they are 1's, rather
> than trigger an illegal instruction if they aren't.
>
AMD's document is explicit about it:
This instruction is always treated as a register-to-register (MOD = 11)
instruction, regardless of the encoding of the MOD field in the MODR/M
byte.
24594.pdf page 316
So i belive this patch should just be applied, thanks.
[..snip..]
--
mailto:av1474@comtv.ru
next prev parent reply other threads:[~2012-07-27 20:53 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-07-27 18:55 [Qemu-devel] [PATCH 0/3] Attempting to run Microport UNIX (ca 1987) Matthew Ogilvie
2012-07-27 18:55 ` [Qemu-devel] [PATCH 1/3] fix some debug printf 64bit format strings Matthew Ogilvie
2012-07-27 18:55 ` [Qemu-devel] [PATCH 2/3] target-i386/translate.c: mov to/from crN/drN: ignore mod bits Matthew Ogilvie
2012-07-27 20:53 ` malc [this message]
2012-07-27 18:55 ` [Qemu-devel] [PATCH 3/3] HACKS for vga text mode with Microport UNIX (ca 1987) Matthew Ogilvie
2012-07-28 6:33 ` [Qemu-devel] [PATCH 0/3] Attempting to run " Markus Armbruster
2012-07-29 0:26 ` Matthew Ogilvie
2012-07-30 12:29 ` Markus Armbruster
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