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author | Mark Dykes <mardyk01@review.trustedfirmware.org> | 2020-09-09 18:36:08 +0000 |
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committer | TrustedFirmware Code Review <review@review.trustedfirmware.org> | 2020-09-09 18:36:08 +0000 |
commit | 0b96df769f0b89018d9870245bf625437db7093b (patch) | |
tree | 74a1e20b47784199184d2c6d1e038bd61ce4f2bc /lib | |
parent | 7fbb3dbac4eaa842636d058d9896a9672dd6d89d (diff) | |
parent | 75fab6496e5fce9a11b4e3a160ad2e797acc6ee9 (diff) | |
download | trusted-firmware-a-0b96df769f0b89018d9870245bf625437db7093b.tar.gz |
Merge "libc: memset: improve performance by avoiding single byte writes" into integration
Diffstat (limited to 'lib')
-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 d8007d8e94..f9dd4c5dbe 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; } |