OpenTTD/src/cpu.cpp

94 lines
3.0 KiB
C++

/*
* This file is part of OpenTTD.
* OpenTTD 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, version 2.
* OpenTTD 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 OpenTTD. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file cpu.cpp OS/CPU/compiler dependent CPU specific calls. */
#include "stdafx.h"
#include "core/bitmath_func.hpp"
#include "safeguards.h"
/**
* Definitions for CPU detection:
*
* MSVC offers cpu information while gcc only implements in gcc 4.8
* __builtin_cpu_supports and friends
* http://msdn.microsoft.com/library/vstudio/hskdteyh%28v=vs.100%29.aspx
* http://gcc.gnu.org/onlinedocs/gcc/X86-Built-in-Functions.html
*
* Other platforms/architectures don't have CPUID, so zero the info and then
* most (if not all) of the features are set as if they do not exist.
*/
#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
void ottd_cpuid(int info[4], int type)
{
__cpuid(info, type);
}
#elif defined(__x86_64__) || defined(__i386)
void ottd_cpuid(int info[4], int type)
{
#if defined(__i386) && defined(__PIC__)
/* The easy variant would be just cpuid, however... ebx is being used by the GOT (Global Offset Table)
* in case of PIC;
* clobbering ebx is no alternative: some compiler versions don't like this
* and will issue an error message like
* "can't find a register in class 'BREG' while reloading 'asm'"
*/
__asm__ __volatile__ (
"xchgl %%ebx, %1 \n\t"
"cpuid \n\t"
"xchgl %%ebx, %1 \n\t"
: "=a" (info[0]), "=r" (info[1]), "=c" (info[2]), "=d" (info[3])
/* It is safe to write "=r" for (info[1]) as in case that PIC is enabled for i386,
* the compiler will not choose EBX as target register (but something else).
*/
: "a" (type)
);
#else
__asm__ __volatile__ (
"cpuid \n\t"
: "=a" (info[0]), "=b" (info[1]), "=c" (info[2]), "=d" (info[3])
: "a" (type)
);
#endif /* i386 PIC */
}
#elif defined(__e2k__) /* MCST Elbrus 2000*/
void ottd_cpuid(int info[4], int type)
{
info[0] = info[1] = info[2] = info[3] = 0;
if (type == 0) {
info[0] = 1;
} else if (type == 1) {
#if defined(__SSE4_1__)
info[2] |= (1<<19); /* HasCPUIDFlag(1, 2, 19) */
#endif
#if defined(__SSSE3__)
info[2] |= (1<<9); /* HasCPUIDFlag(1, 2, 9) */
#endif
#if defined(__SSE2__)
info[3] |= (1<<26); /* HasCPUIDFlag(1, 3, 26) */
#endif
}
}
#else
void ottd_cpuid(int info[4], int)
{
info[0] = info[1] = info[2] = info[3] = 0;
}
#endif
bool HasCPUIDFlag(uint type, uint index, uint bit)
{
int cpu_info[4] = {-1};
ottd_cpuid(cpu_info, 0);
uint max_info_type = cpu_info[0];
if (max_info_type < type) return false;
ottd_cpuid(cpu_info, type);
return HasBit(cpu_info[index], bit);
}