diff options
Diffstat (limited to 'lib/libc/memset.c')
| -rw-r--r-- | lib/libc/memset.c | 34 |
1 files changed, 32 insertions, 2 deletions
diff --git a/lib/libc/memset.c b/lib/libc/memset.c index d8007d8e9..f9dd4c5db 100644 --- a/lib/libc/memset.c +++ b/lib/libc/memset.c @@ -1,18 +1,48 @@ /* - * Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved. + * 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) { char *ptr = dst; + uint64_t *ptr64; + uint64_t fill = (unsigned char)val; - while (count--) + /* Simplify code below by making sure we write at least one byte. */ + if (count == 0) { + return dst; + } + + /* Handle the first part, until the pointer becomes 64-bit aligned. */ + while (((uintptr_t)ptr & 7)) { + *ptr++ = val; + if (--count == 0) { + 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 = (void *)ptr; + for (; count >= 8; count -= 8) { + *ptr64++ = fill; + } + + /* Handle the remaining part byte-per-byte. */ + ptr = (void *)ptr64; + while (count--) { *ptr++ = val; + } return dst; } |