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authorAlexander Shiyan <shc_work@mail.ru>2016-06-19 21:52:52 +0300
committerSascha Hauer <s.hauer@pengutronix.de>2016-07-05 09:02:40 +0200
commit2049dbb6fe55b6bd42e18dc9853c5b9dafc5149d (patch)
tree435bd43805b7a6114074693a400324dd64b28381 /crypto
parentc672fda23a9bdb3160bf503141962ced41c924d5 (diff)
downloadbarebox-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.c15
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)
{