From 754c677b0bbf3ea6c7d2a73c93848f1b0d68c91e Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Mon, 20 Jun 2011 16:54:15 +0930 Subject: lib: import ccan modules for tdb2 Imported from git://git.ozlabs.org/~ccan/ccan init-1161-g661d41f Signed-off-by: Rusty Russell --- lib/ccan/ilog/_info | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 lib/ccan/ilog/_info (limited to 'lib/ccan/ilog/_info') diff --git a/lib/ccan/ilog/_info b/lib/ccan/ilog/_info new file mode 100644 index 0000000000..56de50d610 --- /dev/null +++ b/lib/ccan/ilog/_info @@ -0,0 +1,47 @@ +/** + * ilog - Integer logarithm. + * + * ilog_32() and ilog_64() compute the minimum number of bits required to store + * an unsigned 32-bit or 64-bit value without any leading zero bits. + * This can also be thought of as the location of the highest set bit, with + * counting starting from one (so that 0 returns 0, 1 returns 1, and 2**31 + * returns 32). + * When the value is known to be non-zero ilog32_nz() and ilog64_nz() can + * compile into as few as two instructions, one of which may get optimized out + * later. + * STATIC_ILOG_32 and STATIC_ILOG_64 allow computation on compile-time + * constants, so other compile-time constants can be derived from them. + * + * Example: + * #include + * #include + * #include + * + * int main(void){ + * int i; + * printf("ilog32(0x%08X)=%i\n",0,ilog32(0)); + * for(i=1;i<=STATIC_ILOG_32(USHRT_MAX);i++){ + * uint32_t v; + * v=(uint32_t)1U<<(i-1); + * //Here we know v is non-zero, so we can use ilog32_nz(). + * printf("ilog32(0x%08X)=%i\n",v,ilog32_nz(v)); + * } + * return 0; + * } + * + * License: LGPL (v2 or later) + * Author: Timothy B. Terriberry + */ +#include +#include +#include "config.h" + +int main(int _argc,const char *_argv[]){ + /*Expect exactly one argument.*/ + if(_argc!=2)return 1; + if(strcmp(_argv[1],"depends")==0){ + printf("ccan/compiler\n"); + return 0; + } + return 1; +} -- cgit