avutil/la: Add function performance testing

This patch supports the use of the "checkasm --bench" testing feature
on loongarch platform.

Change-Id: I42790388d057c9ade0dfa38a19d9c1fd44ca0bc3
Reviewed-by: Shiyou Yin <yinshiyou-hf@loongson.cn>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavutil/loongarch/timer.h

@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2023 Loongson Technology Corporation Limited
+ * Contributed by Hecai Yuan <yuanhecai@loongson.cn>
+ *
+ * This file is part of FFmpeg.
+ *
+ * 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.
+ *
+ * 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 FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_LOONGARCH_TIMER_H
+#define AVUTIL_LOONGARCH_TIMER_H
+
+#include <stdint.h>
+#include "config.h"
+
+#if HAVE_INLINE_ASM
+
+#define AV_READ_TIME read_time
+
+static inline uint64_t read_time(void)
+{
+
+#if ARCH_LOONGARCH64
+    uint64_t a, id;
+    __asm__ volatile ( "rdtime.d  %0, %1" : "=r"(a), "=r"(id) :: );
+    return a;
+#else
+    uint32_t a, id;
+    __asm__ volatile ( "rdtimel.w  %0, %1" : "=r"(a), "=r"(id) :: );
+    return (uint64_t)a;
+#endif
+}
+
+#endif /* HAVE_INLINE_ASM */
+
+#endif /* AVUTIL_LOONGARCH_TIMER_H */

libavutil/timer.h

@@ -61,6 +61,8 @@
 #   include "riscv/timer.h"
 #elif ARCH_X86
 #   include "x86/timer.h"
+#elif ARCH_LOONGARCH
+#   include "loongarch/timer.h"
 #endif
 
 #if !defined(AV_READ_TIME)