x86/x64 CPUID in C#

Question

Related to my other question, please help me debug \"An unhandled exception of type \'System.AccessViolationException\' occurred in Unknown Module. Additional information:

Answer 1

i know this thread is old, but i like this thread very much. after coding, I figure out there is problem to get data while "EAX=7,ECX=0" so, I add "mov ecx, 0" in x64CodeBytes.

private readonly static byte[] x64CodeBytes = {
    0x53,                         // push rbx    this gets clobbered by cpuid

    // rcx is level
    // rdx is buffer.
    // Need to save buffer elsewhere, cpuid overwrites rdx
    // Put buffer in r8, use r8 to reference buffer later.        

    // Save rdx (buffer addy) to r8
    0x49, 0x89, 0xd0,             // mov r8,  rdx

    // Move ecx (level) to eax to call cpuid, call cpuid
    0x89, 0xc8,                   // mov eax, ecx
    0xB9, 0x00, 0x00, 0x00, 0x00, // mov ecx, 0
    0x0F, 0xA2,                   // cpuid

    // Write eax et al to buffer
    0x41, 0x89, 0x40, 0x00,       // mov    dword ptr [r8+0],  eax
    0x41, 0x89, 0x58, 0x04,       // mov    dword ptr [r8+4],  ebx
    0x41, 0x89, 0x48, 0x08,       // mov    dword ptr [r8+8],  ecx
    0x41, 0x89, 0x50, 0x0c,       // mov    dword ptr [r8+12], edx

    0x5b,                         // pop rbx
    0xc3                          // ret
    };