diff options
| author | Richard Henderson <rth@twiddle.net> | 2013-05-29 12:30:51 -0700 |
|---|---|---|
| committer | Anthony Liguori <aliguori@us.ibm.com> | 2013-05-31 12:51:07 -0500 |
| commit | dec3fc9657e0682637de4d5a29d947284d01985c (patch) | |
| tree | 568bf74ee522fd1f9ab1842ba96bd0b18337259a /target-i386/translate.c | |
| parent | 39c93c67c5995bd8db7a3fa3b95dcd4e6bc881a7 (diff) | |
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>
Diffstat (limited to 'target-i386/translate.c')
| -rw-r--r-- | target-i386/translate.c | 30 |
1 files changed, 15 insertions, 15 deletions
diff --git a/target-i386/translate.c b/target-i386/translate.c index 0aeccdbc59..14b0298749 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; |