1 /*
2 * Copyright 2011 The LibYuv Project Authors. All rights reserved.
3 *
4 * Use of this source code is governed by a BSD-style license
5 * that can be found in the LICENSE file in the root of the source
6 * tree. An additional intellectual property rights grant can be found
7 * in the file PATENTS. All contributing project authors may
8 * be found in the AUTHORS file in the root of the source tree.
9 */
10
11 #include "libyuv/cpu_id.h"
12
13 #ifdef _MSC_VER
14 #include <intrin.h> // For __cpuid()
15 #endif
16 #if !defined(__CLR_VER) && defined(_M_X64) && \
17 defined(_MSC_VER) && (_MSC_FULL_VER >= 160040219)
18 #include <immintrin.h> // For _xgetbv()
19 #endif
20
21 #include <stdlib.h> // For getenv()
22
23 // For ArmCpuCaps() but unittested on all platforms
24 #include <stdio.h>
25 #include <string.h>
26
27 #include "libyuv/basic_types.h" // For CPU_X86
28
29 // TODO(fbarchard): Use cpuid.h when gcc 4.4 is used on OSX and Linux.
30 #if (defined(__pic__) || defined(__APPLE__)) && defined(__i386__)
__cpuid(int cpu_info[4],int info_type)31 static __inline void __cpuid(int cpu_info[4], int info_type) {
32 asm volatile ( // NOLINT
33 "mov %%ebx, %%edi \n"
34 "cpuid \n"
35 "xchg %%edi, %%ebx \n"
36 : "=a"(cpu_info[0]), "=D"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
37 : "a"(info_type));
38 }
39 #elif defined(__i386__) || defined(__x86_64__)
__cpuid(int cpu_info[4],int info_type)40 static __inline void __cpuid(int cpu_info[4], int info_type) {
41 asm volatile ( // NOLINT
42 "cpuid \n"
43 : "=a"(cpu_info[0]), "=b"(cpu_info[1]), "=c"(cpu_info[2]), "=d"(cpu_info[3])
44 : "a"(info_type));
45 }
46 #endif
47
48 #ifdef __cplusplus
49 namespace libyuv {
50 extern "C" {
51 #endif
52
53 // Low level cpuid for X86. Returns zeros on other CPUs.
54 #if !defined(__CLR_VER) && (defined(_M_IX86) || defined(_M_X64) || \
55 defined(__i386__) || defined(__x86_64__))
56 LIBYUV_API
CpuId(int cpu_info[4],int info_type)57 void CpuId(int cpu_info[4], int info_type) {
58 __cpuid(cpu_info, info_type);
59 }
60 #else
61 LIBYUV_API
62 void CpuId(int cpu_info[4], int) {
63 cpu_info[0] = cpu_info[1] = cpu_info[2] = cpu_info[3] = 0;
64 }
65 #endif
66
67 // X86 CPUs have xgetbv to detect OS saves high parts of ymm registers.
68 #if !defined(__CLR_VER) && defined(_M_X64) && \
69 defined(_MSC_VER) && (_MSC_FULL_VER >= 160040219)
70 #define HAS_XGETBV
XGetBV(unsigned int xcr)71 static uint32 XGetBV(unsigned int xcr) {
72 return static_cast<uint32>(_xgetbv(xcr));
73 }
74 #elif !defined(__CLR_VER) && defined(_M_IX86)
75 #define HAS_XGETBV
76 __declspec(naked) __declspec(align(16))
XGetBV(unsigned int xcr)77 static uint32 XGetBV(unsigned int xcr) {
78 __asm {
79 mov ecx, [esp + 4] // xcr
80 _asm _emit 0x0f _asm _emit 0x01 _asm _emit 0xd0 // xgetbv for vs2005.
81 ret
82 }
83 }
84 #elif defined(__i386__) || defined(__x86_64__)
85 #define HAS_XGETBV
XGetBV(unsigned int xcr)86 static uint32 XGetBV(unsigned int xcr) {
87 uint32 xcr_feature_mask;
88 asm volatile ( // NOLINT
89 ".byte 0x0f, 0x01, 0xd0\n"
90 : "=a"(xcr_feature_mask)
91 : "c"(xcr)
92 : "memory", "cc", "edx"); // edx unused.
93 return xcr_feature_mask;
94 }
95 #endif
96 #ifdef HAS_XGETBV
97 static const int kXCR_XFEATURE_ENABLED_MASK = 0;
98 #endif
99
100 // based on libvpx arm_cpudetect.c
101 // For Arm, but public to allow testing on any CPU
102 LIBYUV_API
ArmCpuCaps(const char * cpuinfo_name)103 int ArmCpuCaps(const char* cpuinfo_name) {
104 int flags = 0;
105 FILE* fin = fopen(cpuinfo_name, "r");
106 if (fin) {
107 char buf[512];
108 while (fgets(buf, 511, fin)) {
109 if (memcmp(buf, "Features", 8) == 0) {
110 flags |= kCpuInitialized;
111 char* p = strstr(buf, " neon");
112 if (p && (p[5] == ' ' || p[5] == '\n')) {
113 flags |= kCpuHasNEON;
114 break;
115 }
116 }
117 }
118 fclose(fin);
119 }
120 return flags;
121 }
122
123 // CPU detect function for SIMD instruction sets.
124 LIBYUV_API
125 int cpu_info_ = 0;
126
127 // Test environment variable for disabling CPU features. Any non-zero value
128 // to disable. Zero ignored to make it easy to set the variable on/off.
TestEnv(const char * name)129 static bool TestEnv(const char* name) {
130 const char* var = getenv(name);
131 if (var) {
132 if (var[0] != '0') {
133 return true;
134 }
135 }
136 return false;
137 }
138
139 LIBYUV_API
InitCpuFlags(void)140 int InitCpuFlags(void) {
141 #if !defined(__CLR_VER) && defined(CPU_X86)
142 int cpu_info[4];
143 __cpuid(cpu_info, 1);
144 cpu_info_ = ((cpu_info[3] & 0x04000000) ? kCpuHasSSE2 : 0) |
145 ((cpu_info[2] & 0x00000200) ? kCpuHasSSSE3 : 0) |
146 ((cpu_info[2] & 0x00080000) ? kCpuHasSSE41 : 0) |
147 ((cpu_info[2] & 0x00100000) ? kCpuHasSSE42 : 0) |
148 (((cpu_info[2] & 0x18000000) == 0x18000000) ? kCpuHasAVX : 0) |
149 kCpuInitialized | kCpuHasX86;
150 #ifdef HAS_XGETBV
151 if (cpu_info_ & kCpuHasAVX) {
152 __cpuid(cpu_info, 7);
153 if ((cpu_info[1] & 0x00000020) &&
154 ((XGetBV(kXCR_XFEATURE_ENABLED_MASK) & 0x06) == 0x06)) {
155 cpu_info_ |= kCpuHasAVX2;
156 }
157 }
158 #endif
159 // environment variable overrides for testing.
160 if (TestEnv("LIBYUV_DISABLE_X86")) {
161 cpu_info_ &= ~kCpuHasX86;
162 }
163 if (TestEnv("LIBYUV_DISABLE_SSE2")) {
164 cpu_info_ &= ~kCpuHasSSE2;
165 }
166 if (TestEnv("LIBYUV_DISABLE_SSSE3")) {
167 cpu_info_ &= ~kCpuHasSSSE3;
168 }
169 if (TestEnv("LIBYUV_DISABLE_SSE41")) {
170 cpu_info_ &= ~kCpuHasSSE41;
171 }
172 if (TestEnv("LIBYUV_DISABLE_SSE42")) {
173 cpu_info_ &= ~kCpuHasSSE42;
174 }
175 if (TestEnv("LIBYUV_DISABLE_AVX")) {
176 cpu_info_ &= ~kCpuHasAVX;
177 }
178 if (TestEnv("LIBYUV_DISABLE_AVX2")) {
179 cpu_info_ &= ~kCpuHasAVX2;
180 }
181 if (TestEnv("LIBYUV_DISABLE_ASM")) {
182 cpu_info_ = kCpuInitialized;
183 }
184 #elif defined(__arm__)
185 #if defined(__linux__) && (defined(__ARM_NEON__) || defined(LIBYUV_NEON))
186 // linux arm parse text file for neon detect.
187 cpu_info_ = ArmCpuCaps("/proc/cpuinfo");
188 #elif defined(__ARM_NEON__)
189 // gcc -mfpu=neon defines __ARM_NEON__
190 // Enable Neon if you want support for Neon and Arm, and use MaskCpuFlags
191 // to disable Neon on devices that do not have it.
192 cpu_info_ = kCpuHasNEON;
193 #endif
194 cpu_info_ |= kCpuInitialized | kCpuHasARM;
195 if (TestEnv("LIBYUV_DISABLE_NEON")) {
196 cpu_info_ &= ~kCpuHasNEON;
197 }
198 if (TestEnv("LIBYUV_DISABLE_ASM")) {
199 cpu_info_ = kCpuInitialized;
200 }
201 #endif // __arm__
202 return cpu_info_;
203 }
204
205 LIBYUV_API
MaskCpuFlags(int enable_flags)206 void MaskCpuFlags(int enable_flags) {
207 InitCpuFlags();
208 cpu_info_ = (cpu_info_ & enable_flags) | kCpuInitialized;
209 }
210
211 #ifdef __cplusplus
212 } // extern "C"
213 } // namespace libyuv
214 #endif
215