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__)
31static __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__)
40static __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
49namespace libyuv {
50extern "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__))
56LIBYUV_API
57void CpuId(int cpu_info[4], int info_type) {
58  __cpuid(cpu_info, info_type);
59}
60#else
61LIBYUV_API
62void 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
71static 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))
77static 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
86static 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
97static 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
102LIBYUV_API
103int 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.
124LIBYUV_API
125int 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.
129static 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
139LIBYUV_API
140int 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
205LIBYUV_API
206void 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