How to Reliably Detect CPU Architecture at Compile Time?

Determining CPU Architecture at Compile Time

Detecting the CPU architecture when compiling code is essential for creating tailored software. However, the proliferation of compilers with their own set of preprocessor definitions complicates the process.

Standard Detection Method

Regrettably, there is no standardized approach to detect CPU architecture. Compilers utilize their own non-standard preprocessor definitions, such as _M_X86 for MSVS, i386 for GCC, and arm for GCC.

Comprehensive Predefined Definitions

In the absence of a standard detection method, a comprehensive list of preprocessor definitions for various compilers is essential. Such a resource would provide a centralized repository of #ifdef macros for detecting different architectures.

Reliable Architecture Detection

One reliable approach to detect CPU architecture involves using a custom function that leverages multiple preprocessor definitions. This function can detect a wide range of architectures, including x86, ARM, MIPS, PowerPC, and others.

Here is an example of a function that performs architecture detection:

extern "C" {
    const char *getBuild() { //Get current architecture, detectx nearly every architecture. Coded by Freak
        #if defined(__x86_64__) || defined(_M_X64)
        return "x86_64";
        #elif defined(i386) || defined(__i386__) || defined(__i386) || defined(_M_IX86)
        return "x86_32";
        #elif defined(__ARM_ARCH_2__)
        return "ARM2";
        #elif defined(__ARM_ARCH_3__) || defined(__ARM_ARCH_3M__)
        return "ARM3";
        #elif defined(__ARM_ARCH_4T__) || defined(__TARGET_ARM_4T)
        return "ARM4T";
        #elif defined(__ARM_ARCH_5_) || defined(__ARM_ARCH_5E_)
        return "ARM5"
        #elif defined(__ARM_ARCH_6T2_) || defined(__ARM_ARCH_6T2_)
        return "ARM6T2";
        #elif defined(__ARM_ARCH_6__) || defined(__ARM_ARCH_6J__) || defined(__ARM_ARCH_6K__) || defined(__ARM_ARCH_6Z__) || defined(__ARM_ARCH_6ZK__)
        return "ARM6";
        #elif defined(__ARM_ARCH_7__) || defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__)
        return "ARM7";
        #elif defined(__ARM_ARCH_7A__) || defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__)
        return "ARM7A";
        #elif defined(__ARM_ARCH_7R__) || defined(__ARM_ARCH_7M__) || defined(__ARM_ARCH_7S__)
        return "ARM7R";
        #elif defined(__ARM_ARCH_7M__)
        return "ARM7M";
        #elif defined(__ARM_ARCH_7S__)
        return "ARM7S";
        #elif defined(__aarch64__) || defined(_M_ARM64)
        return "ARM64";
        #elif defined(mips) || defined(__mips__) || defined(__mips)
        return "MIPS";
        #elif defined(__sh__)
        return "SUPERH";
        #elif defined(__powerpc) || defined(__powerpc__) || defined(__powerpc64__) || defined(__POWERPC__) || defined(__ppc__) || defined(__PPC__) || defined(_ARCH_PPC)
        return "POWERPC";
        #elif defined(__PPC64__) || defined(__ppc64__) || defined(_ARCH_PPC64)
        return "POWERPC64";
        #elif defined(__sparc__) || defined(__sparc)
        return "SPARC";
        #elif defined(__m68k__)
        return "M68K";
        #else
        return "UNKNOWN";
        #endif
    }
}

This function can be used to reliably detect CPU architecture during compilation, allowing for the creation of architecture-specific code.

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