/**
* @file			cpu_feature.c
* @brief		CPU feature detection (CPU ID)
* @author		Patrick Roth - roth@stettbacher.ch
* @copyright	Stettbacher Signal Processing AG
* 
* @remarks
*
* <PRE>
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* </PRE>
*
*/


#if __x86_64__

#include <stdio.h>
#include <cpuid.h>
#include <stdint.h>

#include "cpu_feature.h"


// level 1
static int cpu_feature_sse;
static int cpu_feature_sse2;
static int cpu_feature_sse3;
static int cpu_feature_ssse3;
static int cpu_feature_fma;
static int cpu_feature_avx;

// level 7
static int cpu_feature_avx2;


/**
 * Check whether given CPU feature is available or not.
 * 
 * @param type CPU feature type to check
 * @return not 0 if available, 0 if not
 */
int cpu_feature_support(enum cpu_feature_t type) {
	
	/*
	 * Any CPU feature is disabled on 32 bit machine.
	 */
	switch(type) {
		case CPU_FEATURE_SSE:		return cpu_feature_sse;
		case CPU_FEATURE_SSE2:		return cpu_feature_sse2;
		case CPU_FEATURE_SSE3:		return cpu_feature_sse3;
		case CPU_FEATURE_SSSE3:		return cpu_feature_ssse3;
		case CPU_FEATURE_FMA:		return cpu_feature_fma;
		case CPU_FEATURE_AVX:		return cpu_feature_avx;
		case CPU_FEATURE_AVX2:		return cpu_feature_avx2;
	}
	return 0;
}


/**
 * Initialize CPU features detection like MMX, SSE, SSE2, AVX etc.
 * This function read and handles the CPU IDs.
 * 
 * @return 0 on success otherwise -1
 */
int cpu_feature_init(void) {
	
	unsigned int cpuid_basic, /*cpuid_highest, */sig;
	unsigned int eax, ebx, ecx, edx;
	
	
	cpuid_basic = __get_cpuid_max(0, &sig);
	if(cpuid_basic == 0) {
		printf("%s: Basic CPUID is not supported\n", __func__);
		return -1;
	}
// 	cpuid_highest = __get_cpuid_max(0x8000000, NULL);
	
	if(cpuid_basic >= 1) {
		__cpuid_count(1, 0, eax, ebx, ecx, edx);
		
		cpu_feature_sse		= (edx & bit_SSE) != 0 ? 1:0;
		cpu_feature_sse2	= (edx & bit_SSE2) != 0 ? 1:0;
		
		cpu_feature_sse3	= (ecx & bit_SSE3) != 0 ? 1:0;
		cpu_feature_ssse3	= (ecx & bit_SSSE3) != 0 ? 1:0;
		cpu_feature_fma		= (ecx & bit_FMA) != 0 ? 1:0;
		cpu_feature_avx		= (ecx & bit_AVX) != 0 ? 1:0;
	}
	
	if(cpuid_basic >= 7) {
		__cpuid_count(7, 0, eax, ebx, ecx, edx);
		
		cpu_feature_avx2	= (ebx & bit_AVX2) != 0 ? 1:0;
	}
	
// 	printf("%s: SSE        %s\n", __func__, cpu_feature_sse != 0 ? "yes":"no");
// 	printf("%s: SSE2       %s\n", __func__, cpu_feature_sse2 != 0 ? "yes":"no");
// 	printf("%s: SSE3       %s\n", __func__, cpu_feature_sse3 != 0 ? "yes":"no");
// 	printf("%s: SSSE3      %s\n", __func__, cpu_feature_ssse3 != 0 ? "yes":"no");
// 	printf("%s: FMA        %s\n", __func__, cpu_feature_fma != 0 ? "yes":"no");
// 	printf("%s: AVX        %s\n", __func__, cpu_feature_avx != 0 ? "yes":"no");
// 	printf("%s: AVX2       %s\n", __func__, cpu_feature_avx2 != 0 ? "yes":"no");
	return 0; 
}

#endif // __x86_64__