OpenTTD Source  1.11.2
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 <http://www.gnu.org/licenses/>.
6  */
7 
10 #include "stdafx.h"
11 #include "core/bitmath_func.hpp"
12 
13 #include "safeguards.h"
14 
15 #undef RDTSC_AVAILABLE
16 
17 /* rdtsc for MSC_VER, uses simple inline assembly, or _rdtsc
18  * from external win64.asm because VS2005 does not support inline assembly */
19 #if defined(_MSC_VER) && !defined(RDTSC_AVAILABLE)
20 #include <intrin.h>
21 #include <windows.h>
22 uint64 ottd_rdtsc()
23 {
24 #if defined(_M_ARM)
25  return __rdpmccntr64();
26 #elif defined(_M_ARM64)
27  return _ReadStatusReg(ARM64_PMCCNTR_EL0);
28 #else
29  return __rdtsc();
30 #endif
31 }
32 #define RDTSC_AVAILABLE
33 #endif
34 
35 /* rdtsc for OS/2. Hopefully this works, who knows */
36 #if defined (__WATCOMC__) && !defined(RDTSC_AVAILABLE)
37 unsigned __int64 ottd_rdtsc();
38 # pragma aux ottd_rdtsc = 0x0F 0x31 value [edx eax] parm nomemory modify exact [edx eax] nomemory;
39 # define RDTSC_AVAILABLE
40 #endif
41 
42 /* rdtsc for all other *nix-en (hopefully). Use GCC syntax */
43 #if (defined(__i386__) || defined(__x86_64__)) && !defined(RDTSC_AVAILABLE)
44 uint64 ottd_rdtsc()
45 {
46  uint32 high, low;
47  __asm__ __volatile__ ("rdtsc" : "=a" (low), "=d" (high));
48  return ((uint64)high << 32) | low;
49 }
50 # define RDTSC_AVAILABLE
51 #endif
52 
53 /* rdtsc for PPC which has this not */
54 #if (defined(__POWERPC__) || defined(__powerpc__)) && !defined(RDTSC_AVAILABLE)
55 uint64 ottd_rdtsc()
56 {
57  uint32 high = 0, high2 = 0, low;
58  /* PPC does not have rdtsc, so we cheat by reading the two 32-bit time-counters
59  * it has, 'Move From Time Base (Upper)'. Since these are two reads, in the
60  * very unlikely event that the lower part overflows to the upper part while we
61  * read it; we double-check and reread the registers */
62  asm volatile (
63  "mftbu %0\n"
64  "mftb %1\n"
65  "mftbu %2\n"
66  "cmpw %3,%4\n"
67  "bne- $-16\n"
68  : "=r" (high), "=r" (low), "=r" (high2)
69  : "0" (high), "2" (high2)
70  );
71  return ((uint64)high << 32) | low;
72 }
73 # define RDTSC_AVAILABLE
74 #endif
75 
76 #if defined(__EMSCRIPTEN__) && !defined(RDTSC_AVAILABLE)
77 /* On emscripten doing TIC/TOC would be ill-advised */
78 uint64 ottd_rdtsc() {return 0;}
79 # define RDTSC_AVAILABLE
80 #endif
81 
82 /* In all other cases we have no support for rdtsc. No major issue,
83  * you just won't be able to profile your code with TIC()/TOC() */
84 #if !defined(RDTSC_AVAILABLE)
85 #warning "(non-fatal) No support for rdtsc(), you won't be able to profile with TIC/TOC"
86 uint64 ottd_rdtsc() {return 0;}
87 #endif
88 
89 
101 #if defined(_MSC_VER) && (defined(_M_IX86) || defined(_M_X64))
102 void ottd_cpuid(int info[4], int type)
103 {
104  __cpuid(info, type);
105 }
106 #elif defined(__x86_64__) || defined(__i386)
107 void ottd_cpuid(int info[4], int type)
108 {
109 #if defined(__i386) && defined(__PIC__)
110  /* The easy variant would be just cpuid, however... ebx is being used by the GOT (Global Offset Table)
111  * in case of PIC;
112  * clobbering ebx is no alternative: some compiler versions don't like this
113  * and will issue an error message like
114  * "can't find a register in class 'BREG' while reloading 'asm'"
115  */
116  __asm__ __volatile__ (
117  "xchgl %%ebx, %1 \n\t"
118  "cpuid \n\t"
119  "xchgl %%ebx, %1 \n\t"
120  : "=a" (info[0]), "=r" (info[1]), "=c" (info[2]), "=d" (info[3])
121  /* It is safe to write "=r" for (info[1]) as in case that PIC is enabled for i386,
122  * the compiler will not choose EBX as target register (but something else).
123  */
124  : "a" (type)
125  );
126 #else
127  __asm__ __volatile__ (
128  "cpuid \n\t"
129  : "=a" (info[0]), "=b" (info[1]), "=c" (info[2]), "=d" (info[3])
130  : "a" (type)
131  );
132 #endif /* i386 PIC */
133 }
134 #else
135 void ottd_cpuid(int info[4], int type)
136 {
137  info[0] = info[1] = info[2] = info[3] = 0;
138 }
139 #endif
140 
141 bool HasCPUIDFlag(uint type, uint index, uint bit)
142 {
143  int cpu_info[4] = {-1};
144  ottd_cpuid(cpu_info, 0);
145  uint max_info_type = cpu_info[0];
146  if (max_info_type < type) return false;
147 
148  ottd_cpuid(cpu_info, type);
149  return HasBit(cpu_info[index], bit);
150 }
ottd_cpuid
void ottd_cpuid(int info[4], int type)
Definitions for CPU detection:
Definition: cpu.cpp:135
HasBit
static bool HasBit(const T x, const uint8 y)
Checks if a bit in a value is set.
Definition: bitmath_func.hpp:103
bitmath_func.hpp
safeguards.h
stdafx.h
ottd_rdtsc
uint64 ottd_rdtsc()
Get the tick counter from the CPU (high precision timing).
Definition: cpu.cpp:86
HasCPUIDFlag
bool HasCPUIDFlag(uint type, uint index, uint bit)
Check whether the current CPU has the given flag.
Definition: cpu.cpp:141