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x86 BZHI semantic bug
Description of problem:
The result of instruction BZHI is different from the CPU. The value of destination register and SF of EFLAGS are different.
Steps to reproduce:
1. Compile this code
```
void main() {
asm("mov rax, 0xb1aa9da2fe33fe3");
asm("mov rbx, 0x80000000ffffffff");
asm("mov rcx, 0xf3fce8829b99a5c6");
asm("bzhi rax, rbx, rcx");
}
```
2. Execute and compare the result with the CPU.
- CPU
- RAX = 0x0x80000000ffffffff
- SF = 1
- QEMU
- RAX = 0xffffffff
- SF = 0
Additional information:
This bug is discovered by research conducted by KAIST SoftSec.
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