It is a NOP. The following are typcially used as NOP. They all do the same thing but they result in machine code of different length. Depending on the alignment requirement one of them is chosen: xchg eax, eax = 90 mov eax, eax = 89 C0 lea eax, [eax + 0x00] = 8D 40 … Read more
Yes they do. AMD even provides the specification up to the HD4000 series at the moment. Take a look here at AMD’s R700 instruction set reference guide. There is also an open source project called Nouveau that does reverse engineering of the Nvidia instruction sets. Note that Nvidia has a slightly different architecture than AMD … Read more
As others have mentioned, processor affinity is Operating System specific. If you want to do this outside the confines of the operating system, you’re in for a lot of fun, and by that I mean pain. That said, others have mentioned SetProcessAffinityMask for Win32. Nobody has mentioned the Linux kernel way to set processor affinity, … Read more
The unix.linux file command is great for this. It can generally detect the target architecture and operating system for a given binary (and has been maintained on and off since 1973. wow!) Of course, if you’re not running under unix/linux – you’re a bit stuck. I’m currently trying to find a java based port that … Read more
The ARM processor has 2 instruction sets, the traditional ARM set, where the instructions are all 32-bit long, and the more condensed Thumb set, where most common instructions are 16-bit long (and some are 32-bit long). Which instruction set to run can be chosen by the developer, and only one set can be active (i.e. … Read more
I’ve created a GitHub repro that will detect CPU and OS support for all the major x86 ISA extensions: https://github.com/Mysticial/FeatureDetector Here’s a shorter version: First you need to access the CPUID instruction: #ifdef _WIN32 // Windows #define cpuid(info, x) __cpuidex(info, x, 0) #else // GCC Intrinsics #include <cpuid.h> void cpuid(int info[4], int InfoType){ __cpuid_count(InfoType, 0, … Read more