b57c1da81e
This allows compiling optimised functions for features not enabled in the core build and selecting these at runtime if the system has the necessary support. Signed-off-by: Mans Rullgard <mans@mansr.com>
114 lines
3.1 KiB
C
114 lines
3.1 KiB
C
/*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/cpu.h"
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#include "config.h"
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#define CORE_FLAG(f) \
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(AV_CPU_FLAG_ ## f * (HAVE_ ## f ## _EXTERNAL || HAVE_ ## f ## _INLINE))
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#define CORE_CPU_FLAGS \
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(CORE_FLAG(ARMV5TE) | \
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CORE_FLAG(ARMV6) | \
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CORE_FLAG(ARMV6T2) | \
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CORE_FLAG(VFP) | \
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CORE_FLAG(VFPV3) | \
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CORE_FLAG(NEON))
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#if defined __linux__ || defined __ANDROID__
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#include <stdint.h>
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#include <stdio.h>
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#define AT_HWCAP 16
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/* Relevant HWCAP values from kernel headers */
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#define HWCAP_VFP (1 << 6)
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#define HWCAP_EDSP (1 << 7)
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#define HWCAP_THUMBEE (1 << 11)
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#define HWCAP_NEON (1 << 12)
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#define HWCAP_VFPv3 (1 << 13)
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#define HWCAP_TLS (1 << 15)
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static int get_hwcap(uint32_t *hwcap)
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{
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struct { uint32_t a_type; uint32_t a_val; } auxv;
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FILE *f = fopen("/proc/self/auxv", "r");
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int err = -1;
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if (!f)
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return -1;
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while (fread(&auxv, sizeof(auxv), 1, f) > 0) {
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if (auxv.a_type == AT_HWCAP) {
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*hwcap = auxv.a_val;
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err = 0;
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break;
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}
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}
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fclose(f);
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return err;
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}
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int ff_get_cpu_flags_arm(void)
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{
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int flags = CORE_CPU_FLAGS;
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uint32_t hwcap;
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if (get_hwcap(&hwcap) < 0)
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return flags;
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#define check_cap(cap, flag) do { \
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if (hwcap & HWCAP_ ## cap) \
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flags |= AV_CPU_FLAG_ ## flag; \
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} while (0)
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/* No flags explicitly indicate v6 or v6T2 so check others which
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imply support. */
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check_cap(EDSP, ARMV5TE);
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check_cap(TLS, ARMV6);
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check_cap(THUMBEE, ARMV6T2);
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check_cap(VFP, VFP);
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check_cap(VFPv3, VFPV3);
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check_cap(NEON, NEON);
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/* The v6 checks above are not reliable so let higher flags
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trickle down. */
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if (flags & (AV_CPU_FLAG_VFPV3 | AV_CPU_FLAG_NEON))
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flags |= AV_CPU_FLAG_ARMV6T2;
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if (flags & AV_CPU_FLAG_ARMV6T2)
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flags |= AV_CPU_FLAG_ARMV6;
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return flags;
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}
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#else
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int ff_get_cpu_flags_arm(void)
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{
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return AV_CPU_FLAG_ARMV5TE * HAVE_ARMV5TE |
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AV_CPU_FLAG_ARMV6 * HAVE_ARMV6 |
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AV_CPU_FLAG_ARMV6T2 * HAVE_ARMV6T2 |
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AV_CPU_FLAG_VFP * HAVE_VFP |
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AV_CPU_FLAG_VFPV3 * HAVE_VFPV3 |
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AV_CPU_FLAG_NEON * HAVE_NEON;
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}
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#endif
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