mirror of
https://github.com/OpenTTD/OpenTTD.git
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Rubidium
89 lines
3.1 KiB
C++
89 lines
3.1 KiB
C++
/*
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* This file is part of OpenTTD.
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* 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.
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* 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.
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* 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 <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
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*/
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/** @file cpu.cpp OS/CPU/compiler dependent CPU specific calls. */
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#include "stdafx.h"
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#include "core/bitmath_func.hpp"
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#include "safeguards.h"
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/** Container for CPUID information. */
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using CPUIDArray = std::array<int, 4>;
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/**
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* Get the CPUID information from the CPU.
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*
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* Definitions for CPU detection:
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*
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* MSVC offers cpu information while gcc only implements in gcc 4.8
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* __builtin_cpu_supports and friends
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* http://msdn.microsoft.com/library/vstudio/hskdteyh%28v=vs.100%29.aspx
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* http://gcc.gnu.org/onlinedocs/gcc/X86-Built-in-Functions.html
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*
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* Other platforms/architectures don't have CPUID, so zero the info and then
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* most (if not all) of the features are set as if they do not exist.
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* @param type The information this instruction should retrieve.
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* @return The retrieved info. All zeros on architectures without CPUID.
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*/
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static CPUIDArray CPUID([[maybe_unused]] int type)
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{
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CPUIDArray info{};
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#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
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__cpuid(info.data(), type);
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#elif defined(__i386) && defined(__PIC__)
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/* The easy variant would be just cpuid, however... ebx is being used by the GOT (Global Offset Table)
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* in case of PIC;
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* clobbering ebx is no alternative: some compiler versions don't like this
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* and will issue an error message like
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* "can't find a register in class 'BREG' while reloading 'asm'"
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*/
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__asm__ __volatile__ (
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"xchgl %%ebx, %1 \n\t"
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"cpuid \n\t"
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"xchgl %%ebx, %1 \n\t"
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: "=a" (info[0]), "=r" (info[1]), "=c" (info[2]), "=d" (info[3])
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/* It is safe to write "=r" for (info[1]) as in case that PIC is enabled for i386,
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* the compiler will not choose EBX as target register (but something else).
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*/
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: "a" (type)
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);
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#elif defined(__x86_64__) || defined(__i386)
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__asm__ __volatile__ (
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"cpuid \n\t"
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: "=a" (info[0]), "=b" (info[1]), "=c" (info[2]), "=d" (info[3])
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: "a" (type)
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);
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#elif defined(__e2k__) /* MCST Elbrus 2000*/
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if (type == 0) {
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info[0] = 1;
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} else if (type == 1) {
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# if defined(__SSE4_1__)
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info[2] |= (1<<19); /* HasCPUIDFlag(1, 2, 19) */
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# endif
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# if defined(__SSSE3__)
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info[2] |= (1<<9); /* HasCPUIDFlag(1, 2, 9) */
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# endif
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# if defined(__SSE2__)
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info[3] |= (1<<26); /* HasCPUIDFlag(1, 3, 26) */
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# endif
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}
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}
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#endif
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return info;
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}
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bool HasCPUIDFlag(uint type, uint index, uint bit)
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{
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CPUIDArray cpu_info = CPUID(0);
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uint max_info_type = cpu_info[0];
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if (max_info_type < type) return false;
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cpu_info = CPUID(type);
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return HasBit(cpu_info[index], bit);
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}
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