x86: 1.000
assembly: 0.985
semantic: 0.981
i386: 0.962
debug: 0.206
register: 0.172
operating system: 0.060
performance: 0.033
kernel: 0.027
files: 0.026
TCG: 0.018
architecture: 0.012
virtual: 0.011
user-level: 0.010
PID: 0.009
peripherals: 0.007
device: 0.006
risc-v: 0.005
VMM: 0.005
alpha: 0.005
hypervisor: 0.004
network: 0.004
permissions: 0.003
boot: 0.003
KVM: 0.003
graphic: 0.003
socket: 0.002
vnc: 0.001
mistranslation: 0.001
ppc: 0.000
arm: 0.000

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

Compile this code


void main() {
    asm("blsi rax, rbx");
}



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.