From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp37.i.mail.ru ([94.100.177.97]) by bombadil.infradead.org with esmtps (Exim 4.80.1 #2 (Red Hat Linux)) id 1bEhqS-0003yT-AD for barebox@lists.infradead.org; Sun, 19 Jun 2016 18:53:22 +0000 From: Alexander Shiyan Date: Sun, 19 Jun 2016 21:52:52 +0300 Message-Id: <1466362372-4248-1-git-send-email-shc_work@mail.ru> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH] crypto: crc32: Optimize dynamic CRC table generation To: barebox@lists.infradead.org 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 --- crypto/crc32.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-) diff --git a/crypto/crc32.c b/crypto/crc32.c index 3bff6fe..c510c31 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 = malloc(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) { -- 2.4.9 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox