summaryrefslogtreecommitdiff
path: root/src/cpu.cpp
blob: bafa0f735256d5c8fc51cd8ce49228b4ac484f93 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
/*
 * 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"

#undef RDTSC_AVAILABLE

/* rdtsc for MSC_VER, uses simple inline assembly, or _rdtsc
 * from external win64.asm because VS2005 does not support inline assembly */
#if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64)) && !defined(RDTSC_AVAILABLE)
#include <intrin.h>
uint64 ottd_rdtsc()
{
	return __rdtsc();
}
#define RDTSC_AVAILABLE
#endif

/* rdtsc for OS/2. Hopefully this works, who knows */
#if defined (__WATCOMC__) && !defined(RDTSC_AVAILABLE)
unsigned __int64 ottd_rdtsc();
# pragma aux ottd_rdtsc = 0x0F 0x31 value [edx eax] parm nomemory modify exact [edx eax] nomemory;
# define RDTSC_AVAILABLE
#endif

/* rdtsc for all other *nix-en (hopefully). Use GCC syntax */
#if (defined(__i386__) || defined(__x86_64__)) && !defined(RDTSC_AVAILABLE)
uint64 ottd_rdtsc()
{
	uint32 high, low;
	__asm__ __volatile__ ("rdtsc" : "=a" (low), "=d" (high));
	return ((uint64)high << 32) | low;
}
# define RDTSC_AVAILABLE
#endif

/* rdtsc for PPC which has this not */
#if (defined(__POWERPC__) || defined(__powerpc__)) && !defined(RDTSC_AVAILABLE)
uint64 ottd_rdtsc()
{
	uint32 high = 0, high2 = 0, low;
	/* PPC does not have rdtsc, so we cheat by reading the two 32-bit time-counters
	 * it has, 'Move From Time Base (Upper)'. Since these are two reads, in the
	 * very unlikely event that the lower part overflows to the upper part while we
	 * read it; we double-check and reread the registers */
	asm volatile (
				  "mftbu %0\n"
				  "mftb %1\n"
				  "mftbu %2\n"
				  "cmpw %3,%4\n"
				  "bne- $-16\n"
				  : "=r" (high), "=r" (low), "=r" (high2)
				  : "0" (high), "2" (high2)
				  );
	return ((uint64)high << 32) | low;
}
# define RDTSC_AVAILABLE
#endif

#if defined(__EMSCRIPTEN__) && !defined(RDTSC_AVAILABLE)
/* On emscripten doing TIC/TOC would be ill-advised */
uint64 ottd_rdtsc() {return 0;}
# define RDTSC_AVAILABLE
#endif

/* In all other cases we have no support for rdtsc. No major issue,
 * you just won't be able to profile your code with TIC()/TOC() */
#if !defined(RDTSC_AVAILABLE)
#warning "(non-fatal) No support for rdtsc(), you won't be able to profile with TIC/TOC"
uint64 ottd_rdtsc() {return 0;}
#endif


/**
 * 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 */
}
#else
void ottd_cpuid(int info[4], int type)
{
	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);
}