FFmpeg coverage

Directory: ../../../ffmpeg/
File: src/libavutil/x86/cpu.c
Date: 2025-10-19 01:36:17
Exec Total Coverage
Lines: 70 95 73.7%
Functions: 2 2 100.0%
Branches: 45 118 38.1%
Line Branch Exec Source
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 10197 int ff_get_cpu_flags_x86(void)
91 {
92 10197 int rval = 0;
93
94 #ifdef cpuid
95
96 int eax, ebx, ecx, edx;
97 10197 int max_std_level, max_ext_level, std_caps = 0, ext_caps = 0;
98 10197 int family = 0, model = 0;
99 union { int i[3]; char c[12]; } vendor;
100 10197 int xcr0_lo = 0, xcr0_hi = 0;
101
102 if (!cpuid_test())
103 return 0; /* CPUID not supported */
104
105 10197 cpuid(0, max_std_level, vendor.i[0], vendor.i[2], vendor.i[1]);
106
107
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 10197 if (max_std_level >= 1) {
108 10197 cpuid(1, eax, ebx, ecx, std_caps);
109 10197 family = ((eax >> 8) & 0xf) + ((eax >> 20) & 0xff);
110 10197 model = ((eax >> 4) & 0xf) + ((eax >> 12) & 0xf0);
111
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 10197 if (std_caps & (1 << 15))
112 10197 rval |= AV_CPU_FLAG_CMOV;
113
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 10197 if (std_caps & (1 << 23))
114 10197 rval |= AV_CPU_FLAG_MMX;
115
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 10197 if (std_caps & (1 << 25))
116 10197 rval |= AV_CPU_FLAG_MMXEXT;
117 #if HAVE_SSE
118
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 10197 if (std_caps & (1 << 25))
119 10197 rval |= AV_CPU_FLAG_SSE;
120
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 10197 if (std_caps & (1 << 26))
121 10197 rval |= AV_CPU_FLAG_SSE2;
122
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 10197 if (ecx & 1)
123 10197 rval |= AV_CPU_FLAG_SSE3;
124
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 10197 if (ecx & 0x00000200 )
125 10197 rval |= AV_CPU_FLAG_SSSE3;
126
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 10197 if (ecx & 0x00080000 )
127 10197 rval |= AV_CPU_FLAG_SSE4;
128
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 10197 if (ecx & 0x00100000 )
129 10197 rval |= AV_CPU_FLAG_SSE42;
130
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 10197 if (ecx & 0x02000000 )
131 10197 rval |= AV_CPU_FLAG_AESNI;
132 #if HAVE_AVX
133 /* Check OXSAVE and AVX bits */
134
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 10197 if ((ecx & 0x18000000) == 0x18000000) {
135 /* Check for OS support */
136 10197 xgetbv(0, xcr0_lo, xcr0_hi);
137
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 10197 if ((xcr0_lo & 0x6) == 0x6) {
138 10197 rval |= AV_CPU_FLAG_AVX;
139
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 10197 if (ecx & 0x00001000)
140 10197 rval |= AV_CPU_FLAG_FMA3;
141 }
142 }
143 #endif /* HAVE_AVX */
144 #endif /* HAVE_SSE */
145 }
146
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 10197 if (max_std_level >= 7) {
147 10197 cpuid(7, eax, ebx, ecx, edx);
148 #if HAVE_AVX2
149
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 10197 if ((rval & AV_CPU_FLAG_AVX) && (ebx & 0x00000020))
150 10197 rval |= AV_CPU_FLAG_AVX2;
151 #if HAVE_AVX512 /* F, CD, BW, DQ, VL */
152
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 10197 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
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 10197 if (ebx & 0x00000008) {
165 10197 rval |= AV_CPU_FLAG_BMI1;
166
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 10197 if (ebx & 0x00000100)
167 10197 rval |= AV_CPU_FLAG_BMI2;
168 }
169 }
170
171 10197 cpuid(0x80000000, max_ext_level, ebx, ecx, edx);
172
173
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 10197 if (max_ext_level >= 0x80000001) {
174 10197 cpuid(0x80000001, eax, ebx, ecx, ext_caps);
175
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 10197 if (ext_caps & (1U << 31))
176 ✗ rval |= AV_CPU_FLAG_3DNOW;
177
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 10197 if (ext_caps & (1 << 30))
178 ✗ rval |= AV_CPU_FLAG_3DNOWEXT;
179
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 10197 if (ext_caps & (1 << 23))
180 ✗ rval |= AV_CPU_FLAG_MMX;
181
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 10197 if (ext_caps & (1 << 22))
182 ✗ rval |= AV_CPU_FLAG_MMXEXT;
183
184
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 10197 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
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 10197 if (rval & AV_CPU_FLAG_AVX) {
212
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 10197 if (ecx & 0x00000800)
213 ✗ rval |= AV_CPU_FLAG_XOP;
214
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 10197 if (ecx & 0x00010000)
215 ✗ rval |= AV_CPU_FLAG_FMA4;
216 }
217 }
218
219
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 10197 if (!strncmp(vendor.c, "GenuineIntel", 12)) {
220
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 10197 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
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 10197 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
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 10197 if ((rval & AV_CPU_FLAG_SSSE3) && !(rval & AV_CPU_FLAG_SSE4) &&
244 ✗ family == 6 && model < 23)
245 ✗ rval |= AV_CPU_FLAG_SSSE3SLOW;
246
247 /* Ice Lake and below have slow gather due to Gather Data Sampling
248 * mitigation. */
249
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 10197 if ((rval & AV_CPU_FLAG_AVX2) && family == 6 && model < 143)
250 10197 rval |= AV_CPU_FLAG_SLOW_GATHER;
251 }
252
253 #endif /* cpuid */
254
255 10197 return rval;
256 }
257
258 365037 size_t ff_get_cpu_max_align_x86(void)
259 {
260 365037 int flags = av_get_cpu_flags();
261
262
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 365037 if (flags & AV_CPU_FLAG_AVX512)
263 ✗ return 64;
264
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 365037 if (flags & (AV_CPU_FLAG_AVX2 |
265 AV_CPU_FLAG_AVX |
266 AV_CPU_FLAG_XOP |
267 AV_CPU_FLAG_FMA4 |
268 AV_CPU_FLAG_FMA3 |
269 AV_CPU_FLAG_AVXSLOW))
270 29358 return 32;
271
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 335679 if (flags & (AV_CPU_FLAG_AESNI |
272 AV_CPU_FLAG_SSE42 |
273 AV_CPU_FLAG_SSE4 |
274 AV_CPU_FLAG_SSSE3 |
275 AV_CPU_FLAG_SSE3 |
276 AV_CPU_FLAG_SSE2 |
277 AV_CPU_FLAG_SSE |
278 AV_CPU_FLAG_ATOM |
279 AV_CPU_FLAG_SSSE3SLOW |
280 AV_CPU_FLAG_SSE3SLOW |
281 AV_CPU_FLAG_SSE2SLOW))
282 ✗ return 16;
283
284 335679 return 8;
285 }
286