Floating point instruction virtualization error

VMProtect
1

Hi,

I was testing latest version of VMProtect (3.0.2.470) and it seems that it cannot virtualize fldcw instruction. What’s interesting its counterpart fstcw compiles without problems.

Here’s a minimal sample to reproduce this issue (compile using VS):

__declspec(noinline) void vmProtectionFailureTest()
{
	unsigned short cw;
	__asm
	{
		fstcw cw
		fldcw cw
	}
}

int main()
{
	vmProtectionFailureTest();
	return 0;
}

Protection settings and compilation log:

2

Thank you for your report. We’ll fix it in next build.

3

Wow… so much to learn!

4

Thanks for fixing this issue in 3.0.3.481. Unfortunately I’ve found another corner case for virtualization:

Again it’s suprising that complementary pushad is handled properly but popad is not.

5

Thank you for your report.