OpenTTD Source: src/cpu.cpp Source File

OpenTTD Source 15.3

cpu.cpp
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1/*
2 * This file is part of OpenTTD.
3 * 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.
4 * 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.
5 * 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>.
6 */
7
10#include "stdafx.h"
11#include "core/bitmath_func.hpp"
12
13#include "safeguards.h"
14
26#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
27void ottd_cpuid(int info[4], int type)
28{
29 __cpuid(info, type);
30}
31#elif defined(__x86_64__) || defined(__i386)
32void ottd_cpuid(int info[4], int type)
33{
34#if defined(__i386) && defined(__PIC__)
35 /* The easy variant would be just cpuid, however... ebx is being used by the GOT (Global Offset Table)
36 * in case of PIC;
37 * clobbering ebx is no alternative: some compiler versions don't like this
38 * and will issue an error message like
39 * "can't find a register in class 'BREG' while reloading 'asm'"
40 */
41 __asm__ __volatile__ (
42 "xchgl %%ebx, %1 \n\t"
43 "cpuid \n\t"
44 "xchgl %%ebx, %1 \n\t"
45 : "=a" (info[0]), "=r" (info[1]), "=c" (info[2]), "=d" (info[3])
46 /* It is safe to write "=r" for (info[1]) as in case that PIC is enabled for i386,
47 * the compiler will not choose EBX as target register (but something else).
48 */
49 : "a" (type)
50 );
51#else
52 __asm__ __volatile__ (
53 "cpuid \n\t"
54 : "=a" (info[0]), "=b" (info[1]), "=c" (info[2]), "=d" (info[3])
55 : "a" (type)
56 );
57#endif /* i386 PIC */
58}
59#elif defined(__e2k__) /* MCST Elbrus 2000*/
60void ottd_cpuid(int info[4], int type)
61{
62 info[0] = info[1] = info[2] = info[3] = 0;
63 if (type == 0) {
64 info[0] = 1;
65 } else if (type == 1) {
66#if defined(__SSE4_1__)
67 info[2] |= (1<<19); /* HasCPUIDFlag(1, 2, 19) */
68#endif
69#if defined(__SSSE3__)
70 info[2] |= (1<<9); /* HasCPUIDFlag(1, 2, 9) */
71#endif
72#if defined(__SSE2__)
73 info[3] |= (1<<26); /* HasCPUIDFlag(1, 3, 26) */
74#endif
75 }
76}
77#else
78 void ottd_cpuid(int info[4], int)
79{
80 info[0] = info[1] = info[2] = info[3] = 0;
81}
82#endif
83
84 bool HasCPUIDFlag(uint type, uint index, uint bit)
85{
86 int cpu_info[4] = {-1};
87 ottd_cpuid(cpu_info, 0);
88 uint max_info_type = cpu_info[0];
89 if (max_info_type < type) return false;
90
91 ottd_cpuid(cpu_info, type);
92 return HasBit(cpu_info[index], bit);
93}
bitmath_func.hpp
Functions related to bit mathematics.
HasBit
constexpr bool HasBit(const T x, const uint8_t y)
Checks if a bit in a value is set.
Definition bitmath_func.hpp:103
HasCPUIDFlag
bool HasCPUIDFlag(uint type, uint index, uint bit)
Check whether the current CPU has the given flag.
Definition cpu.cpp:84
ottd_cpuid
void ottd_cpuid(int info[4], int)
Definitions for CPU detection:
Definition cpu.cpp:78
safeguards.h
A number of safeguards to prevent using unsafe methods.
stdafx.h
Definition of base types and functions in a cross-platform compatible way.