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Upstream-Status: Backported
From dec3fc9657e0682637de4d5a29d947284d01985c Mon Sep 17 00:00:00 2001
From: Richard Henderson <rth@twiddle.net>
Date: Wed, 29 May 2013 12:30:51 -0700
Subject: [PATCH] target-i386: Fix aflag logic for CODE64 and the 0x67 prefix
The code reorganization in commit 4a6fd938 broke handling of PREFIX_ADR.
While fixing this, tidy and comment the code so that it's more obvious
what's going on in setting both aflag and dflag.
The TARGET_X86_64 ifdef can be eliminated because CODE64 expands to the
constant zero when TARGET_X86_64 is undefined.
Cc: Paolo Bonzini <pbonzini@redhat.com>
Reported-by: Laszlo Ersek <lersek@redhat.com>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1369855851-21400-1-git-send-email-rth@twiddle.net
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
---
target-i386/translate.c | 30 +++++++++++++++---------------
1 file changed, 15 insertions(+), 15 deletions(-)
diff --git a/target-i386/translate.c b/target-i386/translate.c
index 0aeccdb..14b0298 100644
--- a/target-i386/translate.c
+++ b/target-i386/translate.c
@@ -4677,8 +4677,6 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s,
}
s->pc = pc_start;
prefixes = 0;
- aflag = s->code32;
- dflag = s->code32;
s->override = -1;
rex_w = -1;
rex_r = 0;
@@ -4801,23 +4799,25 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s,
}
/* Post-process prefixes. */
- if (prefixes & PREFIX_DATA) {
- dflag ^= 1;
- }
- if (prefixes & PREFIX_ADR) {
- aflag ^= 1;
- }
-#ifdef TARGET_X86_64
if (CODE64(s)) {
- if (rex_w == 1) {
- /* 0x66 is ignored if rex.w is set */
- dflag = 2;
+ /* In 64-bit mode, the default data size is 32-bit. Select 64-bit
+ data with rex_w, and 16-bit data with 0x66; rex_w takes precedence
+ over 0x66 if both are present. */
+ dflag = (rex_w > 0 ? 2 : prefixes & PREFIX_DATA ? 0 : 1);
+ /* In 64-bit mode, 0x67 selects 32-bit addressing. */
+ aflag = (prefixes & PREFIX_ADR ? 1 : 2);
+ } else {
+ /* In 16/32-bit mode, 0x66 selects the opposite data size. */
+ dflag = s->code32;
+ if (prefixes & PREFIX_DATA) {
+ dflag ^= 1;
}
- if (!(prefixes & PREFIX_ADR)) {
- aflag = 2;
+ /* In 16/32-bit mode, 0x67 selects the opposite addressing. */
+ aflag = s->code32;
+ if (prefixes & PREFIX_ADR) {
+ aflag ^= 1;
}
}
-#endif
s->prefix = prefixes;
s->aflag = aflag;
--
1.7.9.5
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