yuzu/unicorn
1
0
Fork 0
mirror of https://github.com/yuzu-emu/unicorn.git synced 2025-01-03 15:55:37 +00:00
Code Issues Packages Projects Releases Wiki Activity

target/i386: Fix decoding of certain BMI instructions

Browse source 
This patch fixes a translation bug for a subset of x86 BMI instructions
such as the following:

c4 e2 f9 f7 c0 shlxq %rax, %rax, %rax

Currently, these incorrectly generate an undefined instruction exception
when SSE is disabled via CR4, while instructions like "shrxq" work fine.

The problem appears to be related to BMI instructions encoded using VEX
and with a mandatory prefix of "0x66" (data). Instructions with this
data prefix (such as shlxq) are currently rejected. Instructions with
other mandatory prefixes (such as shrxq) translate as expected.

This patch removes the incorrect check in "gen_sse" that causes the
exception to be generated. For the non-BMI cases, the check is
redundant: prefixes are already checked at line 3696.

Buglink: https://bugs.launchpad.net/qemu/+bug/1748296

Backports 51909241d26fe6fe18a08def93ccc8273f61a8b3
This commit is contained in:
David Greenaway 2021-03-04 18:08:37 -05:00 committed by Lioncash
parent 56afe9f919
commit 0c1c359b5c
1 changed files with 1 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
qemu/target/i386/translate.c
View file

@ -3531,7 +3531,7 @@ static void gen_sse(CPUX86State *env, DisasContext *s, int b,
}
if (is_xmm
&& !(s->flags & HF_OSFXSR_MASK)
&& ((b != 0x38 && b != 0x3a) || (s->prefix & PREFIX_DATA))) {
&& (b != 0x38 && b != 0x3a)) {
goto unknown_op;
}
if (b == 0x0e) {