summaryrefslogtreecommitdiff
path: root/src/base
diff options
context:
space:
mode:
authorGabe Black <gblack@eecs.umich.edu>2009-07-01 22:16:36 -0700
committerGabe Black <gblack@eecs.umich.edu>2009-07-01 22:16:36 -0700
commit7172e26cc446556e6b8241549d5d188b5cb0cd37 (patch)
tree38ac996fee85f4ed7a03c0e8e4f725a46821675e /src/base
parentf5141c23fd63c0fd89828ebf91317b1bd7f77881 (diff)
downloadgem5-7172e26cc446556e6b8241549d5d188b5cb0cd37.tar.xz
ARM: Add a findLsbSet function and use it to implement clz.
Diffstat (limited to 'src/base')
-rw-r--r--src/base/bitfield.hh17
1 files changed, 17 insertions, 0 deletions
diff --git a/src/base/bitfield.hh b/src/base/bitfield.hh
index 28093a5d4..cc3695159 100644
--- a/src/base/bitfield.hh
+++ b/src/base/bitfield.hh
@@ -161,4 +161,21 @@ findMsbSet(uint64_t val) {
return msb;
}
+/**
+ * Returns the bit position of the LSB that is set in the input
+ */
+inline int
+findLsbSet(uint64_t val) {
+ int lsb = 0;
+ if (!val)
+ return sizeof(val) * 8;
+ if (!bits(val, 31,0)) { lsb += 32; val >>= 32; }
+ if (!bits(val, 15,0)) { lsb += 16; val >>= 16; }
+ if (!bits(val, 7,0)) { lsb += 8; val >>= 8; }
+ if (!bits(val, 3,0)) { lsb += 4; val >>= 4; }
+ if (!bits(val, 1,0)) { lsb += 2; val >>= 2; }
+ if (!bits(val, 0,0)) { lsb += 1; }
+ return lsb;
+}
+
#endif // __BASE_BITFIELD_HH__