From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [PATCH 0/8] Simplify byte/word opcode pair decode
Date: Mon, 23 Aug 2010 15:29:18 +0200
Message-ID: <4C7277AE.3040102@redhat.com>
References: <1282561577-24491-1-git-send-email-avi@redhat.com>
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Cc: kvm@vger.kernel.org
To: Avi Kivity <avi@redhat.com>
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On 08/23/2010 01:06 PM, Avi Kivity wrote:
> Many x86 instructions come in pairs - byte and word variants where bit 0
> of the opcode determines operand size.  Use this to simplify the decode
> tables.

Many actually come in quadruples, bit 0 is the size and bit 1 says which 
of ModRM and REG is the destination.

example:

D2bv(DstMem | SrcReg | ModRM | Lock), D2bv(DstReg | SrcMem | ModRM),

Paolo