// Copyright (C) 2021 Jérôme "Lynix" Leclercq (lynix680@gmail.com)
// This file is part of the "Nazara Engine - Core module"
// For conditions of distribution and use, see copyright notice in Config.hpp

#include <Nazara/Core/Win32/HardwareInfoImpl.hpp>
#include <Nazara/Core/Error.hpp>
#include <windows.h>

#ifdef NAZARA_COMPILER_MSVC
	#include <intrin.h>
#endif

#include <Nazara/Core/Debug.hpp>

namespace Nz
{
	void HardwareInfoImpl::Cpuid(UInt32 functionId, UInt32 subFunctionId, UInt32 registers[4])
	{
	#if defined(NAZARA_COMPILER_MSVC)
		static_assert(sizeof(UInt32) == sizeof(int), "Assertion failed");

		// Use intrinsic function if available
		__cpuidex(reinterpret_cast<int*>(registers), static_cast<int>(functionId), static_cast<int>(subFunctionId));
	#elif defined(NAZARA_COMPILER_CLANG) || defined(NAZARA_COMPILER_GCC) || defined(NAZARA_COMPILER_INTEL)
		// https://en.wikipedia.org/wiki/CPUID
		asm volatile(
			#ifdef NAZARA_PLATFORM_x64
			"pushq %%rbx     \n\t" // save %rbx
			#else
			"pushl %%ebx     \n\t" // save %ebx
			#endif
			"cpuid            \n\t"
			"movl %%ebx ,%[ebx]  \n\t" // write the result into output var
			#ifdef NAZARA_PLATFORM_x64
			"popq %%rbx \n\t"
			#else
			"popl %%ebx \n\t"
			#endif
			: "=a"(registers[0]), [ebx] "=r"(registers[1]), "=c"(registers[2]), "=d"(registers[3]) // output
			: "a"(functionId), "c" (subFunctionId));                                               // input
	#else
		NazaraInternalError("Cpuid has been called although it is not supported");
	#endif
	}

	unsigned int HardwareInfoImpl::GetProcessorCount()
	{
		// Simpler (and more portable) than using CPUID
		SYSTEM_INFO infos;
		GetNativeSystemInfo(&infos);

		return infos.dwNumberOfProcessors;
	}

	UInt64 HardwareInfoImpl::GetTotalMemory()
	{
		MEMORYSTATUSEX memStatus;
		memStatus.dwLength = sizeof(memStatus);
		GlobalMemoryStatusEx(&memStatus);

		return memStatus.ullTotalPhys;
	}

	bool HardwareInfoImpl::IsCpuidSupported()
	{
	#ifdef NAZARA_PLATFORM_x64
		return true; // cpuid is always supported on x64 arch
	#else
		#if defined(NAZARA_COMPILER_MSVC)
		int supported;
		__asm
		{
			pushfd
			pop  eax
			mov  ecx, eax
			xor  eax, 0x200000
			push eax
			popfd
			pushfd
			pop  eax
			xor  eax, ecx
			mov  supported, eax
			push ecx
			popfd
		};

		return supported != 0;
		#elif defined(NAZARA_COMPILER_CLANG) || defined(NAZARA_COMPILER_GCC) || defined(NAZARA_COMPILER_INTEL)
		int supported;
		asm volatile (" pushfl\n"
		              " pop %%eax\n"
		              " mov %%eax, %%ecx\n"
		              " xor $0x200000, %%eax\n"
		              " push %%eax\n"
		              " popfl\n"
		              " pushfl\n"
		              " pop %%eax\n"
		              " xor %%ecx, %%eax\n"
		              " mov %%eax, %0\n"
		              " push %%ecx\n"
		              " popfl"
		              : "=m" (supported)         // output
		              :                          // input
		              : "eax", "ecx", "memory"); // clobbered register

		return supported != 0;
		#else
		return false;
		#endif
	#endif
	}
}