[rtems commit] bsps/powerpc: Add ppc_count_leading_zeros()

[Sebastian Huber]

Module:    rtems
Branch:    master
Commit:    4fe3ad2f99fc21db2f58c9bfb2a5e8cf5237cc63
Changeset: http://git.rtems.org/rtems/commit/?id=4fe3ad2f99fc21db2f58c9bfb2a5e8cf5237cc63

Author:    Sebastian Huber <sebastian.huber at embedded-brains.de>
Date:      Tue Jul  9 16:37:32 2013 +0200

bsps/powerpc: Add ppc_count_leading_zeros()

---

 .../powerpc/shared/include/powerpc-utility.h       |   13 +++++++++++++
 1 files changed, 13 insertions(+), 0 deletions(-)

diff --git a/c/src/lib/libcpu/powerpc/shared/include/powerpc-utility.h b/c/src/lib/libcpu/powerpc/shared/include/powerpc-utility.h
index 79024eb..71567d5 100644
--- a/c/src/lib/libcpu/powerpc/shared/include/powerpc-utility.h
+++ b/c/src/lib/libcpu/powerpc/shared/include/powerpc-utility.h
@@ -407,6 +407,19 @@ static inline void ppc_external_exceptions_disable(uint32_t msr)
   RTEMS_COMPILER_MEMORY_BARRIER();
 }
 
+static inline uint32_t ppc_count_leading_zeros(uint32_t value)
+{
+  uint32_t count;
+
+  __asm__ (
+    "cntlzw %0, %1;"
+    : "=r" (count)
+    : "r" (value)
+  );
+
+  return count;
+}
+
 /*
  *  Simple spin delay in microsecond units for device drivers.
  *  This is very dependent on the clock speed of the target.