diff options
Diffstat (limited to 'lib/builtins/popcountsi2.c')
| -rw-r--r-- | lib/builtins/popcountsi2.c | 26 |
1 files changed, 12 insertions, 14 deletions
diff --git a/lib/builtins/popcountsi2.c b/lib/builtins/popcountsi2.c index 4162ba7b0..77c1a3145 100644 --- a/lib/builtins/popcountsi2.c +++ b/lib/builtins/popcountsi2.c @@ -15,18 +15,16 @@ /* Returns: count of 1 bits */ -COMPILER_RT_ABI si_int -__popcountsi2(si_int a) -{ - su_int x = (su_int)a; - x = x - ((x >> 1) & 0x55555555); - /* Every 2 bits holds the sum of every pair of bits */ - x = ((x >> 2) & 0x33333333) + (x & 0x33333333); - /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) */ - x = (x + (x >> 4)) & 0x0F0F0F0F; - /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) */ - x = (x + (x >> 16)); - /* The lower 16 bits hold two 8 bit sums (5 significant bits).*/ - /* Upper 16 bits are garbage */ - return (x + (x >> 8)) & 0x0000003F; /* (6 significant bits) */ +COMPILER_RT_ABI si_int __popcountsi2(si_int a) { + su_int x = (su_int)a; + x = x - ((x >> 1) & 0x55555555); + /* Every 2 bits holds the sum of every pair of bits */ + x = ((x >> 2) & 0x33333333) + (x & 0x33333333); + /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) */ + x = (x + (x >> 4)) & 0x0F0F0F0F; + /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) */ + x = (x + (x >> 16)); + /* The lower 16 bits hold two 8 bit sums (5 significant bits).*/ + /* Upper 16 bits are garbage */ + return (x + (x >> 8)) & 0x0000003F; /* (6 significant bits) */ } |