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/*
* Copyright 2013 Knowledge Economy Developments Ltd
*
* Henry Gomersall
* heng@kedevelopments.co.uk
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* Small utilities for inspecting the CPU */
#ifndef CPU_H
#define CPU_H
#if __STDC_VERSION__ >= 199901L
/* "inline" is a keyword */
#else
# define inline static
#endif
#if defined(__amd64__) || defined (_M_X64) || defined(__i386__) || defined(_M_IX86) || defined(_X86_)
#define AVX_WORD 2
#define AVX_BIT 28
#define SSE_WORD 3
#define SSE_BIT 25
#ifdef _MSC_VER
/* Visual Studio Code */
#include <intrin.h>
#define cpuid(func, cpuinfo)\
__cpuid(cpuinfo, func);
#else
/* generic x86 Assembly code (based on wikipedia example)
* Firstly it's necessary to move ebx into an interim
* register to protect it (cpuid clobbers eax, ebx ecx and edx)
* */
#define cpuid(func, cpuinfo)\
cpuinfo[0] = func; /* Load the first entry with the func id */\
__asm__ __volatile__ \
("mov %%ebx, %%edi;" /* 32bit PIC: don't clobber ebx */ \
"cpuid;" \
"mov %%ebx, %%esi;" \
"mov %%edi, %%ebx;" \
:"+a" (cpuinfo[0]), "=S" (cpuinfo[1]), /* eax rw, esi read */ \
"=c" (cpuinfo[2]), "=d" (cpuinfo[3]) /* ecx read, edx read */\
: :"edi")
#endif
/* Returns the byte alignment for optimum simd operations */
inline int simd_alignment(void){
int cpuinfo[4];
/* This gets the cpuinfo (set by 1)*/
cpuid(1, cpuinfo);
if (cpuinfo[AVX_WORD] & (1<<AVX_BIT)) /* AVX */
return 32;
else if (cpuinfo[SSE_WORD] & (1<<SSE_BIT)) /* SSE */
return 16;
else /* No SIMD */
return 4;
}
#else
inline int simd_alignment(void){
return 4;
}
#endif
#endif /* Header guard */
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