diff options
Diffstat (limited to 'libavutil/x86/cpu.c')
| -rw-r--r-- | libavutil/x86/cpu.c | 29 |
1 files changed, 20 insertions, 9 deletions
diff --git a/libavutil/x86/cpu.c b/libavutil/x86/cpu.c index 8be6d94742..7a5d4e6a3a 100644 --- a/libavutil/x86/cpu.c +++ b/libavutil/x86/cpu.c @@ -3,20 +3,20 @@ * (c)1997-99 by H. Dietz and R. Fisher * Converted to C and improved by Fabrice Bellard. * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * - * Libav is distributed in the hope that it will be useful, + * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public - * License along with Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -45,7 +45,7 @@ "cpuid \n\t" \ "xchg %%"REG_b", %%"REG_S \ : "=a" (eax), "=S" (ebx), "=c" (ecx), "=d" (edx) \ - : "0" (index)) + : "0" (index), "2"(0)) #define xgetbv(index, eax, edx) \ __asm__ (".byte 0x0f, 0x01, 0xd0" : "=a"(eax), "=d"(edx) : "c" (index)) @@ -143,7 +143,7 @@ int ff_get_cpu_flags_x86(void) if (max_std_level >= 7) { cpuid(7, eax, ebx, ecx, edx); #if HAVE_AVX2 - if (ebx & 0x00000020) + if ((rval & AV_CPU_FLAG_AVX) && (ebx & 0x00000020)) rval |= AV_CPU_FLAG_AVX2; #endif /* HAVE_AVX2 */ /* BMI1/2 don't need OS support */ @@ -167,6 +167,7 @@ int ff_get_cpu_flags_x86(void) if (ext_caps & (1 << 22)) rval |= AV_CPU_FLAG_MMXEXT; + if (!strncmp(vendor.c, "AuthenticAMD", 12)) { /* Allow for selectively disabling SSE2 functions on AMD processors with SSE2 support but not SSE4a. This includes Athlon64, some Opteron, and some Sempron processors. MMX, SSE, or 3DNow! are faster @@ -174,9 +175,19 @@ int ff_get_cpu_flags_x86(void) AV_CPU_FLAG_SSE2 and AV_CPU_FLAG_SSE2SLOW are both set in this case so that SSE2 is used unless explicitly disabled by checking AV_CPU_FLAG_SSE2SLOW. */ - if (!strncmp(vendor.c, "AuthenticAMD", 12) && - rval & AV_CPU_FLAG_SSE2 && !(ecx & 0x00000040)) { - rval |= AV_CPU_FLAG_SSE2SLOW; + if (rval & AV_CPU_FLAG_SSE2 && !(ecx & 0x00000040)) + rval |= AV_CPU_FLAG_SSE2SLOW; + + /* Similar to the above but for AVX functions on AMD processors. + This is necessary only for functions using YMM registers on Bulldozer + based CPUs as they lack 256-bits execution units. SSE/AVX functions + using XMM registers are always faster on them. + AV_CPU_FLAG_AVX and AV_CPU_FLAG_AVXSLOW are both set so that AVX is + used unless explicitly disabled by checking AV_CPU_FLAG_AVXSLOW. + TODO: Confirm if Excavator is affected or not by this once it's + released, and update the check if necessary. Same for btver2. */ + if (family == 0x15 && (rval & AV_CPU_FLAG_AVX)) + rval |= AV_CPU_FLAG_AVXSLOW; } /* XOP and FMA4 use the AVX instruction coding scheme, so they can't be |