cpu.c (10231B)
1 /* 2 * CPU detection code, extracted from mmx.h 3 * (c)1997-99 by H. Dietz and R. Fisher 4 * Converted to C and improved by Fabrice Bellard. 5 * 6 * This file is part of FFmpeg. 7 * 8 * FFmpeg is free software; you can redistribute it and/or 9 * modify it under the terms of the GNU Lesser General Public 10 * License as published by the Free Software Foundation; either 11 * version 2.1 of the License, or (at your option) any later version. 12 * 13 * FFmpeg is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16 * Lesser General Public License for more details. 17 * 18 * You should have received a copy of the GNU Lesser General Public 19 * License along with FFmpeg; if not, write to the Free Software 20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA 21 */ 22 23 #include <stdlib.h> 24 #include <string.h> 25 26 #include "libavutil/x86/asm.h" 27 #include "libavutil/x86/cpu.h" 28 #include "libavutil/cpu.h" 29 #include "libavutil/cpu_internal.h" 30 31 #if HAVE_X86ASM 32 33 #define cpuid(index, eax, ebx, ecx, edx) \ 34 ff_cpu_cpuid(index, &eax, &ebx, &ecx, &edx) 35 36 #define xgetbv(index, eax, edx) \ 37 ff_cpu_xgetbv(index, &eax, &edx) 38 39 #elif HAVE_INLINE_ASM 40 41 /* ebx saving is necessary for PIC. gcc seems unable to see it alone */ 42 #define cpuid(index, eax, ebx, ecx, edx) \ 43 __asm__ volatile ( \ 44 "mov %%"FF_REG_b", %%"FF_REG_S" \n\t" \ 45 "cpuid \n\t" \ 46 "xchg %%"FF_REG_b", %%"FF_REG_S \ 47 : "=a" (eax), "=S" (ebx), "=c" (ecx), "=d" (edx) \ 48 : "0" (index), "2"(0)) 49 50 #define xgetbv(index, eax, edx) \ 51 __asm__ (".byte 0x0f, 0x01, 0xd0" : "=a"(eax), "=d"(edx) : "c" (index)) 52 53 #define get_eflags(x) \ 54 __asm__ volatile ("pushfl \n" \ 55 "pop %0 \n" \ 56 : "=r"(x)) 57 58 #define set_eflags(x) \ 59 __asm__ volatile ("push %0 \n" \ 60 "popfl \n" \ 61 :: "r"(x)) 62 63 #endif /* HAVE_INLINE_ASM */ 64 65 #if ARCH_X86_64 66 67 #define cpuid_test() 1 68 69 #elif HAVE_X86ASM 70 71 #define cpuid_test ff_cpu_cpuid_test 72 73 #elif HAVE_INLINE_ASM 74 75 static int cpuid_test(void) 76 { 77 x86_reg a, c; 78 79 /* Check if CPUID is supported by attempting to toggle the ID bit in 80 * the EFLAGS register. */ 81 get_eflags(a); 82 set_eflags(a ^ 0x200000); 83 get_eflags(c); 84 85 return a != c; 86 } 87 #endif 88 89 /* Function to test if multimedia instructions are supported... */ 90 int ff_get_cpu_flags_x86(void) 91 { 92 int rval = 0; 93 94 #ifdef cpuid 95 96 int eax, ebx, ecx, edx; 97 int max_std_level, max_ext_level, std_caps = 0, ext_caps = 0; 98 int family = 0, model = 0; 99 union { int i[3]; char c[12]; } vendor; 100 int xcr0_lo = 0, xcr0_hi = 0; 101 102 if (!cpuid_test()) 103 return 0; /* CPUID not supported */ 104 105 cpuid(0, max_std_level, vendor.i[0], vendor.i[2], vendor.i[1]); 106 107 if (max_std_level >= 1) { 108 cpuid(1, eax, ebx, ecx, std_caps); 109 family = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff); 110 model = ((eax >> 4) & 0xf) + ((eax >> 12) & 0xf0); 111 if (std_caps & (1 << 15)) 112 rval |= AV_CPU_FLAG_CMOV; 113 if (std_caps & (1 << 23)) 114 rval |= AV_CPU_FLAG_MMX; 115 if (std_caps & (1 << 25)) 116 rval |= AV_CPU_FLAG_MMXEXT; 117 #if HAVE_SSE 118 if (std_caps & (1 << 25)) 119 rval |= AV_CPU_FLAG_SSE; 120 if (std_caps & (1 << 26)) 121 rval |= AV_CPU_FLAG_SSE2; 122 if (ecx & 1) 123 rval |= AV_CPU_FLAG_SSE3; 124 if (ecx & 0x00000200 ) 125 rval |= AV_CPU_FLAG_SSSE3; 126 if (ecx & 0x00080000 ) 127 rval |= AV_CPU_FLAG_SSE4; 128 if (ecx & 0x00100000 ) 129 rval |= AV_CPU_FLAG_SSE42; 130 if (ecx & 0x02000000 ) 131 rval |= AV_CPU_FLAG_AESNI; 132 #if HAVE_AVX 133 /* Check OXSAVE and AVX bits */ 134 if ((ecx & 0x18000000) == 0x18000000) { 135 /* Check for OS support */ 136 xgetbv(0, xcr0_lo, xcr0_hi); 137 if ((xcr0_lo & 0x6) == 0x6) { 138 rval |= AV_CPU_FLAG_AVX; 139 if (ecx & 0x00001000) 140 rval |= AV_CPU_FLAG_FMA3; 141 } 142 } 143 #endif /* HAVE_AVX */ 144 #endif /* HAVE_SSE */ 145 } 146 if (max_std_level >= 7) { 147 cpuid(7, eax, ebx, ecx, edx); 148 #if HAVE_AVX2 149 if ((rval & AV_CPU_FLAG_AVX) && (ebx & 0x00000020)) 150 rval |= AV_CPU_FLAG_AVX2; 151 #if HAVE_AVX512 /* F, CD, BW, DQ, VL */ 152 if ((xcr0_lo & 0xe0) == 0xe0) { /* OPMASK/ZMM state */ 153 if ((rval & AV_CPU_FLAG_AVX2) && (ebx & 0xd0030000) == 0xd0030000) { 154 rval |= AV_CPU_FLAG_AVX512; 155 #if HAVE_AVX512ICL 156 if ((ebx & 0xd0200000) == 0xd0200000 && (ecx & 0x5f42) == 0x5f42) 157 rval |= AV_CPU_FLAG_AVX512ICL; 158 #endif /* HAVE_AVX512ICL */ 159 } 160 } 161 #endif /* HAVE_AVX512 */ 162 #endif /* HAVE_AVX2 */ 163 /* BMI1/2 don't need OS support */ 164 if (ebx & 0x00000008) { 165 rval |= AV_CPU_FLAG_BMI1; 166 if (ebx & 0x00000100) 167 rval |= AV_CPU_FLAG_BMI2; 168 } 169 } 170 171 cpuid(0x80000000, max_ext_level, ebx, ecx, edx); 172 173 if (max_ext_level >= 0x80000001) { 174 cpuid(0x80000001, eax, ebx, ecx, ext_caps); 175 if (ext_caps & (1U << 31)) 176 rval |= AV_CPU_FLAG_3DNOW; 177 if (ext_caps & (1 << 30)) 178 rval |= AV_CPU_FLAG_3DNOWEXT; 179 if (ext_caps & (1 << 23)) 180 rval |= AV_CPU_FLAG_MMX; 181 if (ext_caps & (1 << 22)) 182 rval |= AV_CPU_FLAG_MMXEXT; 183 184 if (!strncmp(vendor.c, "AuthenticAMD", 12)) { 185 /* Allow for selectively disabling SSE2 functions on AMD processors 186 with SSE2 support but not SSE4a. This includes Athlon64, some 187 Opteron, and some Sempron processors. MMX, SSE, or 3DNow! are faster 188 than SSE2 often enough to utilize this special-case flag. 189 AV_CPU_FLAG_SSE2 and AV_CPU_FLAG_SSE2SLOW are both set in this case 190 so that SSE2 is used unless explicitly disabled by checking 191 AV_CPU_FLAG_SSE2SLOW. */ 192 if (rval & AV_CPU_FLAG_SSE2 && !(ecx & 0x00000040)) 193 rval |= AV_CPU_FLAG_SSE2SLOW; 194 195 /* Similar to the above but for AVX functions on AMD processors. 196 This is necessary only for functions using YMM registers on Bulldozer 197 and Jaguar based CPUs as they lack 256-bit execution units. SSE/AVX 198 functions using XMM registers are always faster on them. 199 AV_CPU_FLAG_AVX and AV_CPU_FLAG_AVXSLOW are both set so that AVX is 200 used unless explicitly disabled by checking AV_CPU_FLAG_AVXSLOW. */ 201 if ((family == 0x15 || family == 0x16) && (rval & AV_CPU_FLAG_AVX)) 202 rval |= AV_CPU_FLAG_AVXSLOW; 203 204 /* Zen 3 and earlier have slow gather */ 205 if ((family <= 0x19) && (rval & AV_CPU_FLAG_AVX2)) 206 rval |= AV_CPU_FLAG_SLOW_GATHER; 207 } 208 209 /* XOP and FMA4 use the AVX instruction coding scheme, so they can't be 210 * used unless the OS has AVX support. */ 211 if (rval & AV_CPU_FLAG_AVX) { 212 if (ecx & 0x00000800) 213 rval |= AV_CPU_FLAG_XOP; 214 if (ecx & 0x00010000) 215 rval |= AV_CPU_FLAG_FMA4; 216 } 217 } 218 219 if (!strncmp(vendor.c, "GenuineIntel", 12)) { 220 if (family == 6 && (model == 9 || model == 13 || model == 14)) { 221 /* 6/9 (pentium-m "banias"), 6/13 (pentium-m "dothan"), and 222 * 6/14 (core1 "yonah") theoretically support sse2, but it's 223 * usually slower than mmx, so let's just pretend they don't. 224 * AV_CPU_FLAG_SSE2 is disabled and AV_CPU_FLAG_SSE2SLOW is 225 * enabled so that SSE2 is not used unless explicitly enabled 226 * by checking AV_CPU_FLAG_SSE2SLOW. The same situation 227 * applies for AV_CPU_FLAG_SSE3 and AV_CPU_FLAG_SSE3SLOW. */ 228 if (rval & AV_CPU_FLAG_SSE2) 229 rval ^= AV_CPU_FLAG_SSE2SLOW | AV_CPU_FLAG_SSE2; 230 if (rval & AV_CPU_FLAG_SSE3) 231 rval ^= AV_CPU_FLAG_SSE3SLOW | AV_CPU_FLAG_SSE3; 232 } 233 /* The Atom processor has SSSE3 support, which is useful in many cases, 234 * but sometimes the SSSE3 version is slower than the SSE2 equivalent 235 * on the Atom, but is generally faster on other processors supporting 236 * SSSE3. This flag allows for selectively disabling certain SSSE3 237 * functions on the Atom. */ 238 if (family == 6 && model == 28) 239 rval |= AV_CPU_FLAG_ATOM; 240 241 /* Conroe has a slow shuffle unit. Check the model number to ensure not 242 * to include crippled low-end Penryns and Nehalems that lack SSE4. */ 243 if ((rval & AV_CPU_FLAG_SSSE3) && !(rval & AV_CPU_FLAG_SSE4) && 244 family == 6 && model < 23) 245 rval |= AV_CPU_FLAG_SSSE3SLOW; 246 247 /* Haswell has slow gather */ 248 if ((rval & AV_CPU_FLAG_AVX2) && family == 6 && model < 70) 249 rval |= AV_CPU_FLAG_SLOW_GATHER; 250 } 251 252 #endif /* cpuid */ 253 254 return rval; 255 } 256 257 size_t ff_get_cpu_max_align_x86(void) 258 { 259 int flags = av_get_cpu_flags(); 260 261 if (flags & AV_CPU_FLAG_AVX512) 262 return 64; 263 if (flags & (AV_CPU_FLAG_AVX2 | 264 AV_CPU_FLAG_AVX | 265 AV_CPU_FLAG_XOP | 266 AV_CPU_FLAG_FMA4 | 267 AV_CPU_FLAG_FMA3 | 268 AV_CPU_FLAG_AVXSLOW)) 269 return 32; 270 if (flags & (AV_CPU_FLAG_AESNI | 271 AV_CPU_FLAG_SSE42 | 272 AV_CPU_FLAG_SSE4 | 273 AV_CPU_FLAG_SSSE3 | 274 AV_CPU_FLAG_SSE3 | 275 AV_CPU_FLAG_SSE2 | 276 AV_CPU_FLAG_SSE | 277 AV_CPU_FLAG_ATOM | 278 AV_CPU_FLAG_SSSE3SLOW | 279 AV_CPU_FLAG_SSE3SLOW | 280 AV_CPU_FLAG_SSE2SLOW)) 281 return 16; 282 283 return 8; 284 }