x86 BLSI and BLSR semantic bug Description of problem: The result of instruction BLSI and BLSR is different from the CPU. The value of CF is different. Steps to reproduce: 1. Compile this code ``` void main() { asm("blsi rax, rbx"); } ``` 2. Execute and compare the result with the CPU. The value of `CF` is exactly the opposite. This problem happens with BLSR, too. Additional information: This bug is discovered by research conducted by KAIST SoftSec.