diff options
author | Alexander Shiyan <shc_work@mail.ru> | 2016-06-19 21:52:52 +0300 |
---|---|---|
committer | Sascha Hauer <s.hauer@pengutronix.de> | 2016-07-05 09:02:40 +0200 |
commit | 2049dbb6fe55b6bd42e18dc9853c5b9dafc5149d (patch) | |
tree | 435bd43805b7a6114074693a400324dd64b28381 /crypto | |
parent | c672fda23a9bdb3160bf503141962ced41c924d5 (diff) | |
download | barebox-2049dbb6fe55b6bd42e18dc9853c5b9dafc5149d.tar.gz barebox-2049dbb6fe55b6bd42e18dc9853c5b9dafc5149d.tar.xz |
crypto: crc32: Optimize dynamic CRC table generation
In barebox we have an option for dynamic formation of the CRC32
table (DYNAMIC_CRC_TABLE), but the source code declares a static
array which is simply filled with data, the resulting code becomes
even more than without DYNAMIC_CRC_TABLE option, due to the BSS usage.
CONFIG_DYNAMIC_CRC_TABLE=n
text data bss dec hex filename
1884 0 0 1884 75c crc32.o
CONFIG_DYNAMIC_CRC_TABLE=y
text data bss dec hex filename
1066 4 1024 2094 82e crc32.o
This patch provides dynamic buffer allocation for the CRC table,
which saves about 1 Kbyte, as it should be.
CONFIG_DYNAMIC_CRC_TABLE=y
text data bss dec hex filename
1062 0 4 1066 42a crc32.o
Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'crypto')
-rw-r--r-- | crypto/crc32.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/crypto/crc32.c b/crypto/crc32.c index 3bff6feb28..232c023adb 100644 --- a/crypto/crc32.c +++ b/crypto/crc32.c @@ -24,9 +24,7 @@ #ifdef CONFIG_DYNAMIC_CRC_TABLE -static int crc_table_empty = 1; -static ulong crc_table[256]; -static void make_crc_table(void); +static ulong *crc_table; /* Generate a table for a byte-wise 32-bit CRC calculation on the polynomial: @@ -65,6 +63,8 @@ static void make_crc_table(void) for (n = 0; n < sizeof(p)/sizeof(char); n++) poly |= 1L << (31 - p[n]); + crc_table = xmalloc(sizeof(ulong) * 256); + for (n = 0; n < 256; n++) { c = (ulong)n; @@ -72,7 +72,6 @@ static void make_crc_table(void) c = c & 1 ? poly ^ (c >> 1) : c >> 1; crc_table[n] = c; } - crc_table_empty = 0; } #else /* ======================================================================== @@ -147,8 +146,8 @@ STATIC uint32_t crc32(uint32_t crc, const void *_buf, unsigned int len) const unsigned char *buf = _buf; #ifdef CONFIG_DYNAMIC_CRC_TABLE - if (crc_table_empty) - make_crc_table(); + if (!crc_table) + make_crc_table(); #endif crc = crc ^ 0xffffffffL; while (len >= 8) @@ -173,8 +172,8 @@ STATIC uint32_t crc32_no_comp(uint32_t crc, const void *_buf, unsigned int len) const unsigned char *buf = _buf; #ifdef CONFIG_DYNAMIC_CRC_TABLE - if (crc_table_empty) - make_crc_table(); + if (!crc_table) + make_crc_table(); #endif while (len >= 8) { |