diff options
| author |   Aurelien Jarno <aurelien@aurel32.net> | 2010-03-06 18:02:31 +0100 |
|---|---|---|
| committer | Aurelien Jarno <aurelien@aurel32.net> | 2010-03-10 08:52:46 +0100 |
| commit | d2df336c582d74650f4ccc3ef4e84ac86c2868fe (patch) | |
| tree | 4f130f5d89984eea71bd177f9abb05db2dc9071c | |
| parent | Fix segfault with ram_size > 4095M without kvm (diff) | |
| download | qemu-kvm-d2df336c582d74650f4ccc3ef4e84ac86c2868fe.tar.gz qemu-kvm-d2df336c582d74650f4ccc3ef4e84ac86c2868fe.tar.bz2 qemu-kvm-d2df336c582d74650f4ccc3ef4e84ac86c2868fe.zip | |
target-i386: fix SIB decoding with index = 4
A SIB byte with an index of 4 means "no scaled index", even if the scale
value is not 0. In 64-bit mode, if REX.X is used, an index of 4 selects
%r12. This is correctly handled by the computation of the index variable,
which includes the index bits, and also the REX.X prefix:
index = ((code >> 3) & 7) | REX_X(s);
Thanks to Avi Kivity, Jamie Lokier and Malc for the analysis of the
problem and the initial patch.
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
(cherry picked from commit b16f827bdf7444b8cd338b9ecb654b4752f47225)
| -rw-r--r-- | target-i386/translate.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/target-i386/translate.c b/target-i386/translate.c index 0f7255d9d..a61db16ec 100644 --- a/target-i386/translate.c +++ b/target-i386/translate.c @@ -2047,8 +2047,8 @@ static void gen_lea_modrm(DisasContext *s, int modrm, int *reg_ptr, int *offset_ gen_op_movl_A0_im(disp); } } - /* XXX: index == 4 is always invalid */ - if (havesib && (index != 4 || scale != 0)) { + /* index == 4 means no index */ + if (havesib && (index != 4)) { #ifdef TARGET_X86_64 if (s->aflag == 2) { gen_op_addq_A0_reg_sN(scale, index); |