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