GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

source/trusted-firmware/trusted-firmware-a-2.8/lib/libc/memset.c

@@ -0,0 +1,51 @@
+/*
+ * Copyright (c) 2013-2020, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <stddef.h>
+#include <string.h>
+#include <stdint.h>
+
+void *memset(void *dst, int val, size_t count)
+{
+	uint8_t *ptr = dst;
+	uint64_t *ptr64;
+	uint64_t fill = (unsigned char)val;
+
+	/* Simplify code below by making sure we write at least one byte. */
+	if (count == 0U) {
+		return dst;
+	}
+
+	/* Handle the first part, until the pointer becomes 64-bit aligned. */
+	while (((uintptr_t)ptr & 7U) != 0U) {
+		*ptr = (uint8_t)val;
+		ptr++;
+		if (--count == 0U) {
+			return dst;
+		}
+	}
+
+	/* Duplicate the fill byte to the rest of the 64-bit word. */
+	fill |= fill << 8;
+	fill |= fill << 16;
+	fill |= fill << 32;
+
+	/* Use 64-bit writes for as long as possible. */
+	ptr64 = (uint64_t *)ptr;
+	for (; count >= 8U; count -= 8) {
+		*ptr64 = fill;
+		ptr64++;
+	}
+
+	/* Handle the remaining part byte-per-byte. */
+	ptr = (uint8_t *)ptr64;
+	while (count-- > 0U)  {
+		*ptr = (uint8_t)val;
+		ptr++;
+	}
+
+	return dst;
+}