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From: | Richard Henderson |
Subject: | Re: [Qemu-devel] [PATCH] i386/translate: ignore 0x67 (PREFIX_ADR) on TARGET_X86_64 && CODE64() |
Date: | Sat, 25 May 2013 16:23:07 -0700 |
User-agent: | Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130514 Thunderbird/17.0.6 |
On 2013-05-24 14:37, Laszlo Ersek wrote:
@@ -4813,7 +4813,11 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, /* 0x66 is ignored if rex.w is set */ dflag = 2; } - if (!(prefixes & PREFIX_ADR)) { + if (prefixes & PREFIX_ADR) { + /* flip it back, 0x67 should have no effect */ + aflag ^= 1; + } + else { aflag = 2; } }
Agreed that there's a bug here. I'm thinking it would be clearer to not write this as yet another flip, but understand that unlike dflag, aflag can only be
either 1 or 2 in 64-bit mode. I'm thinking of something more like this: r~ diff --git a/target-i386/translate.c b/target-i386/translate.c index 0aeccdb..bf772aa 100644 --- a/target-i386/translate.c +++ b/target-i386/translate.c@@ -4813,9 +4813,8 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s,
/* 0x66 is ignored if rex.w is set */ dflag = 2; } - if (!(prefixes & PREFIX_ADR)) { - aflag = 2; - } + /* 0x67 toggles between 64-bit and 32-bit addressing. */ + aflag = (prefixes & PREFIX_ADR ? 1 : 2); } #endif
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