Import libcompiler_rt 3.9.0, LLVM's replacement for libgcc.

This is the lib/builtin directory of the compiler-rt source tarball.

comments/ok patrick@, ok kettenis@

1 files changed, 36 insertions, 0 deletions

diff --git a/lib/libcompiler_rt/popcountdi2.c b/lib/libcompiler_rt/popcountdi2.c
new file mode 100644
index 00000000000..5e8a62f075e
--- /dev/null
+++ b/lib/libcompiler_rt/popcountdi2.c
@@ -0,0 +1,36 @@
+/* ===-- popcountdi2.c - Implement __popcountdi2 ----------------------------===
+ *
+ *                     The LLVM Compiler Infrastructure
+ *
+ * This file is dual licensed under the MIT and the University of Illinois Open
+ * Source Licenses. See LICENSE.TXT for details.
+ *
+ * ===----------------------------------------------------------------------===
+ *
+ * This file implements __popcountdi2 for the compiler_rt library.
+ *
+ * ===----------------------------------------------------------------------===
+ */
+
+#include "int_lib.h"
+
+/* Returns: count of 1 bits */
+
+COMPILER_RT_ABI si_int
+__popcountdi2(di_int a)
+{
+    du_int x2 = (du_int)a;
+    x2 = x2 - ((x2 >> 1) & 0x5555555555555555uLL);
+    /* Every 2 bits holds the sum of every pair of bits (32) */
+    x2 = ((x2 >> 2) & 0x3333333333333333uLL) + (x2 & 0x3333333333333333uLL);
+    /* Every 4 bits holds the sum of every 4-set of bits (3 significant bits) (16) */
+    x2 = (x2 + (x2 >> 4)) & 0x0F0F0F0F0F0F0F0FuLL;
+    /* Every 8 bits holds the sum of every 8-set of bits (4 significant bits) (8) */
+    su_int x = (su_int)(x2 + (x2 >> 32));
+    /* The lower 32 bits hold four 16 bit sums (5 significant bits). */
+    /*   Upper 32 bits are garbage */
+    x = x + (x >> 16);
+    /* The lower 16 bits hold two 32 bit sums (6 significant bits). */
+    /*   Upper 16 bits are garbage */
+    return (x + (x >> 8)) & 0x0000007F;  /* (7 significant bits) */
+}