SSE CMP ops with 8bit immediate throw sigill with oversized byte
This bug has been copied automatically from: https://bugs.launchpad.net/qemu/+bug/1832422
Reported by 'Sonicadvance1@gmail.com' on 2019-06-12 :
The SSE comparison ops that use an 8bit immediate as a comparison type selector throws a sigill when the immediate is oversized. Test op that I found this on is here `66 0f c2 c0 d1 cmppd xmm0,xmm0,0xd1` According to the x86-64 documentation only bits [2:0] are used for these ops (and [4:0] for the AVX variant) Currently qemu just checks if the value is >=8 and will throw a sigill in that case. It instead needs to mask. I have a small patch that fixes the issue for the SSE variant.