semantic: 0.993
instruction: 0.944
assembly: 0.800
graphic: 0.790
device: 0.717
boot: 0.516
vnc: 0.471
socket: 0.397
mistranslation: 0.337
network: 0.219
other: 0.099
KVM: 0.091

x86 BEXTR semantic bug
Description of problem
The result of instruction BEXTR is different with from the CPU. The value of destination register is different. I think QEMU does not consider the operand size limit.

Steps to reproduce

Compile this code

void main() {
    asm("mov rax, 0x17b3693f77fb6e9");
    asm("mov rbx, 0x8f635a775ad3b9b4");
    asm("mov rcx, 0xb717b75da9983018");
    asm("bextr eax, ebx, ecx");
}

Execute and compare the result with the CPU.

CPU
RAX = 0x5a

QEMU
RAX = 0x635a775a

Additional information
This bug is discovered by research conducted by KAIST SoftSec.