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.
6 * This file is part of FFmpeg.
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.
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.
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
26 #include "libavutil/x86/asm.h"
27 #include "libavutil/x86/cpu.h"
28 #include "libavutil/cpu.h"
29 #include "libavutil/cpu_internal.h"
33 #define cpuid(index, eax, ebx, ecx, edx) \
34 ff_cpu_cpuid(index, &eax, &ebx, &ecx, &edx)
36 #define xgetbv(index, eax, edx) \
37 ff_cpu_xgetbv(index, &eax, &edx)
41 /* ebx saving is necessary for PIC. gcc seems unable to see it alone */
42 #define cpuid(index, eax, ebx, ecx, edx) \
44 "mov %%"FF_REG_b", %%"FF_REG_S" \n\t" \
46 "xchg %%"FF_REG_b", %%"FF_REG_S \
47 : "=a" (eax), "=S" (ebx), "=c" (ecx), "=d" (edx) \
48 : "0" (index), "2"(0))
50 #define xgetbv(index, eax, edx) \
51 __asm__ (".byte 0x0f, 0x01, 0xd0" : "=a"(eax), "=d"(edx) : "c" (index))
53 #define get_eflags(x) \
54 __asm__ volatile ("pushfl \n" \
58 #define set_eflags(x) \
59 __asm__ volatile ("push %0 \n" \
63 #endif /* HAVE_INLINE_ASM */
67 #define cpuid_test() 1
71 #define cpuid_test ff_cpu_cpuid_test
75 static int cpuid_test(void)
79 /* Check if CPUID is supported by attempting to toggle the ID bit in
80 * the EFLAGS register. */
82 set_eflags(a ^ 0x200000);
89 /* Function to test if multimedia instructions are supported... */
90 int ff_get_cpu_flags_x86(void)
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;
102 return 0; /* CPUID not supported */
104 cpuid(0, max_std_level, vendor.i[0], vendor.i[2], vendor.i[1]);
106 if (max_std_level >= 1) {
107 cpuid(1, eax, ebx, ecx, std_caps);
108 family = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff);
109 model = ((eax >> 4) & 0xf) + ((eax >> 12) & 0xf0);
110 if (std_caps & (1 << 15))
111 rval |= AV_CPU_FLAG_CMOV;
112 if (std_caps & (1 << 23))
113 rval |= AV_CPU_FLAG_MMX;
114 if (std_caps & (1 << 25))
115 rval |= AV_CPU_FLAG_MMXEXT;
117 if (std_caps & (1 << 25))
118 rval |= AV_CPU_FLAG_SSE;
119 if (std_caps & (1 << 26))
120 rval |= AV_CPU_FLAG_SSE2;
122 rval |= AV_CPU_FLAG_SSE3;
123 if (ecx & 0x00000200 )
124 rval |= AV_CPU_FLAG_SSSE3;
125 if (ecx & 0x00080000 )
126 rval |= AV_CPU_FLAG_SSE4;
127 if (ecx & 0x00100000 )
128 rval |= AV_CPU_FLAG_SSE42;
129 if (ecx & 0x01000000 )
130 rval |= AV_CPU_FLAG_AESNI;
132 /* Check OXSAVE and AVX bits */
133 if ((ecx & 0x18000000) == 0x18000000) {
134 /* Check for OS support */
136 if ((eax & 0x6) == 0x6) {
137 rval |= AV_CPU_FLAG_AVX;
138 if (ecx & 0x00001000)
139 rval |= AV_CPU_FLAG_FMA3;
142 #endif /* HAVE_AVX */
143 #endif /* HAVE_SSE */
145 if (max_std_level >= 7) {
146 cpuid(7, eax, ebx, ecx, edx);
148 if ((rval & AV_CPU_FLAG_AVX) && (ebx & 0x00000020))
149 rval |= AV_CPU_FLAG_AVX2;
150 #endif /* HAVE_AVX2 */
151 /* BMI1/2 don't need OS support */
152 if (ebx & 0x00000008) {
153 rval |= AV_CPU_FLAG_BMI1;
154 if (ebx & 0x00000100)
155 rval |= AV_CPU_FLAG_BMI2;
159 cpuid(0x80000000, max_ext_level, ebx, ecx, edx);
161 if (max_ext_level >= 0x80000001) {
162 cpuid(0x80000001, eax, ebx, ecx, ext_caps);
163 if (ext_caps & (1U << 31))
164 rval |= AV_CPU_FLAG_3DNOW;
165 if (ext_caps & (1 << 30))
166 rval |= AV_CPU_FLAG_3DNOWEXT;
167 if (ext_caps & (1 << 23))
168 rval |= AV_CPU_FLAG_MMX;
169 if (ext_caps & (1 << 22))
170 rval |= AV_CPU_FLAG_MMXEXT;
172 if (!strncmp(vendor.c, "AuthenticAMD", 12)) {
173 /* Allow for selectively disabling SSE2 functions on AMD processors
174 with SSE2 support but not SSE4a. This includes Athlon64, some
175 Opteron, and some Sempron processors. MMX, SSE, or 3DNow! are faster
176 than SSE2 often enough to utilize this special-case flag.
177 AV_CPU_FLAG_SSE2 and AV_CPU_FLAG_SSE2SLOW are both set in this case
178 so that SSE2 is used unless explicitly disabled by checking
179 AV_CPU_FLAG_SSE2SLOW. */
180 if (rval & AV_CPU_FLAG_SSE2 && !(ecx & 0x00000040))
181 rval |= AV_CPU_FLAG_SSE2SLOW;
183 /* Similar to the above but for AVX functions on AMD processors.
184 This is necessary only for functions using YMM registers on Bulldozer
185 and Jaguar based CPUs as they lack 256-bit execution units. SSE/AVX
186 functions using XMM registers are always faster on them.
187 AV_CPU_FLAG_AVX and AV_CPU_FLAG_AVXSLOW are both set so that AVX is
188 used unless explicitly disabled by checking AV_CPU_FLAG_AVXSLOW. */
189 if ((family == 0x15 || family == 0x16) && (rval & AV_CPU_FLAG_AVX))
190 rval |= AV_CPU_FLAG_AVXSLOW;
193 /* XOP and FMA4 use the AVX instruction coding scheme, so they can't be
194 * used unless the OS has AVX support. */
195 if (rval & AV_CPU_FLAG_AVX) {
196 if (ecx & 0x00000800)
197 rval |= AV_CPU_FLAG_XOP;
198 if (ecx & 0x00010000)
199 rval |= AV_CPU_FLAG_FMA4;
203 if (!strncmp(vendor.c, "GenuineIntel", 12)) {
204 if (family == 6 && (model == 9 || model == 13 || model == 14)) {
205 /* 6/9 (pentium-m "banias"), 6/13 (pentium-m "dothan"), and
206 * 6/14 (core1 "yonah") theoretically support sse2, but it's
207 * usually slower than mmx, so let's just pretend they don't.
208 * AV_CPU_FLAG_SSE2 is disabled and AV_CPU_FLAG_SSE2SLOW is
209 * enabled so that SSE2 is not used unless explicitly enabled
210 * by checking AV_CPU_FLAG_SSE2SLOW. The same situation
211 * applies for AV_CPU_FLAG_SSE3 and AV_CPU_FLAG_SSE3SLOW. */
212 if (rval & AV_CPU_FLAG_SSE2)
213 rval ^= AV_CPU_FLAG_SSE2SLOW | AV_CPU_FLAG_SSE2;
214 if (rval & AV_CPU_FLAG_SSE3)
215 rval ^= AV_CPU_FLAG_SSE3SLOW | AV_CPU_FLAG_SSE3;
217 /* The Atom processor has SSSE3 support, which is useful in many cases,
218 * but sometimes the SSSE3 version is slower than the SSE2 equivalent
219 * on the Atom, but is generally faster on other processors supporting
220 * SSSE3. This flag allows for selectively disabling certain SSSE3
221 * functions on the Atom. */
222 if (family == 6 && model == 28)
223 rval |= AV_CPU_FLAG_ATOM;