#include "cpu_features.h"

// wrappers with uniform prototype for implementation-specific x86 CPU id
#if defined(ARCH_X86_64)
#ifdef __GNUC__
#include <cpuid.h>
#endif

inline void cpuid(int cpuInfo[4], int functionId) {
#if defined(_MSC_VER)
	__cpuid(cpuInfo, functionId);
#elif defined(__GNUC__)
	__cpuid(functionId, cpuInfo[0], cpuInfo[1], cpuInfo[2], cpuInfo[3]);
#else
#error No definition for cpuid
#endif
}

inline void cpuidex(int cpuInfo[4], int functionId, int subFunctionId) {
#if defined(_MSC_VER)
	__cpuidex(cpuInfo, functionId, subFunctionId);
#elif defined(__GNUC__)
	__cpuid_count(functionId, subFunctionId, cpuInfo[0], cpuInfo[1], cpuInfo[2], cpuInfo[3]);
#else
#error No definition for cpuidex
#endif
}
#endif


CPUFeaturesImpl::CPUFeaturesImpl()
{
#if defined(ARCH_X86_64)
	int cpuInfo[4];
	cpuid(cpuInfo, 0x80000001);
	x86.lzcnt = ((cpuInfo[2] >> 5) & 1) != 0;
	cpuid(cpuInfo, 0x1);
	x86.movbe = ((cpuInfo[2] >> 22) & 1) != 0;
	x86.avx = ((cpuInfo[2] >> 28) & 1) != 0;
	x86.aesni = ((cpuInfo[2] >> 25) & 1) != 0;
	x86.ssse3 = ((cpuInfo[2] >> 9) & 1) != 0;
	x86.sse4_1 = ((cpuInfo[2] >> 19) & 1) != 0;
	cpuidex(cpuInfo, 0x7, 0);
	x86.avx2 = ((cpuInfo[1] >> 5) & 1) != 0;
	x86.bmi2 = ((cpuInfo[1] >> 8) & 1) != 0;
	cpuid(cpuInfo, 0x80000007);
	x86.invariant_tsc = ((cpuInfo[3] >> 8) & 1);
	// get CPU brand name
	uint32_t nExIds, i = 0;
	memset(m_cpuBrandName, 0, sizeof(m_cpuBrandName));
	cpuid(cpuInfo, 0x80000000);
	nExIds = (uint32_t)cpuInfo[0];
	for (uint32_t i = 0x80000000; i <= nExIds; ++i)
	{
		cpuid(cpuInfo, i);
		if (i == 0x80000002)
			memcpy(m_cpuBrandName, cpuInfo, sizeof(cpuInfo));
		else if (i == 0x80000003)
			memcpy(m_cpuBrandName + 16, cpuInfo, sizeof(cpuInfo));
		else if (i == 0x80000004)
			memcpy(m_cpuBrandName + 32, cpuInfo, sizeof(cpuInfo));
	}
#endif
}

std::string CPUFeaturesImpl::GetCPUName()
{
	return { m_cpuBrandName };
}

std::string CPUFeaturesImpl::GetCommaSeparatedExtensionList()
{
	std::string tmp;
	auto appendExt = [&tmp](const char* str)
	{
		if (!tmp.empty())
			tmp.append(", ");
		tmp.append(str);
	};
	if (x86.ssse3)
		appendExt("SSSE3");
	if (x86.sse4_1)
		appendExt("SSE4.1");
	if (x86.avx)
		appendExt("AVX");
	if (x86.avx2)
		appendExt("AVX2");
	if (x86.lzcnt)
		appendExt("LZCNT");
	if (x86.movbe)
		appendExt("MOVBE");
	if (x86.bmi2)
		appendExt("BMI2");
	if (x86.aesni)
		appendExt("AES-NI");
	if(x86.invariant_tsc)
		appendExt("INVARIANT-TSC");
	return tmp;
}

CPUFeaturesImpl g_CPUFeatures;