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authorArnaldo Carvalho de Melo <acme@redhat.com>2010-04-30 19:31:12 -0300
committerArnaldo Carvalho de Melo <acme@redhat.com>2010-05-02 12:00:44 -0300
commitfb72014d98afd51e85aab9c061344ef32d615606 (patch)
tree18713d4d1084870c604b512396b893944a2bbdab /tools/perf/util/hweight.c
parentbc4b473f1aa2ef785ccfd890a24a1de5a6660f98 (diff)
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perf tools: Don't use code surrounded by __KERNEL__
We need to refactor code to be explicitely shared by the kernel and at least the tools/ userspace programs, so, till we do that, copy the bare minimum bitmap/bitops code needed by tools/perf. Reported-by: "H. Peter Anvin" <hpa@zytor.com> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <new-submission> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/perf/util/hweight.c')
-rw-r--r--tools/perf/util/hweight.c31
1 files changed, 31 insertions, 0 deletions
diff --git a/tools/perf/util/hweight.c b/tools/perf/util/hweight.c
new file mode 100644
index 0000000..5c1d0d0
--- /dev/null
+++ b/tools/perf/util/hweight.c
@@ -0,0 +1,31 @@
+#include <linux/bitops.h>
+
+/**
+ * hweightN - returns the hamming weight of a N-bit word
+ * @x: the word to weigh
+ *
+ * The Hamming Weight of a number is the total number of bits set in it.
+ */
+
+unsigned int hweight32(unsigned int w)
+{
+ unsigned int res = w - ((w >> 1) & 0x55555555);
+ res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
+ res = (res + (res >> 4)) & 0x0F0F0F0F;
+ res = res + (res >> 8);
+ return (res + (res >> 16)) & 0x000000FF;
+}
+
+unsigned long hweight64(__u64 w)
+{
+#if BITS_PER_LONG == 32
+ return hweight32((unsigned int)(w >> 32)) + hweight32((unsigned int)w);
+#elif BITS_PER_LONG == 64
+ __u64 res = w - ((w >> 1) & 0x5555555555555555ul);
+ res = (res & 0x3333333333333333ul) + ((res >> 2) & 0x3333333333333333ul);
+ res = (res + (res >> 4)) & 0x0F0F0F0F0F0F0F0Ful;
+ res = res + (res >> 8);
+ res = res + (res >> 16);
+ return (res + (res >> 32)) & 0x00000000000000FFul;
+#endif
+}