Initial import of compiler-rt.
-
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@74292 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/udivsi3.c b/lib/udivsi3.c
new file mode 100644
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--- /dev/null
+++ b/lib/udivsi3.c
@@ -0,0 +1,61 @@
+//===-- udivsi3.c - Implement __udivsi3 -----------------------------------===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements __udivsi3 for the compiler_rt library.
+//
+//===----------------------------------------------------------------------===//
+
+#include "int_lib.h"
+
+// Returns: a / b
+
+// Translated from Figure 3-40 of The PowerPC Compiler Writer's Guide
+
+su_int
+__udivsi3(su_int n, su_int d)
+{
+ const unsigned n_uword_bits = sizeof(su_int) * CHAR_BIT;
+ su_int q;
+ su_int r;
+ unsigned sr;
+ // special cases
+ if (d == 0)
+ return 0; // ?!
+ if (n == 0)
+ return 0;
+ sr = __builtin_clz(d) - __builtin_clz(n);
+ // 0 <= sr <= n_uword_bits - 1 or sr large
+ if (sr > n_uword_bits - 1) // d > r
+ return 0;
+ if (sr == n_uword_bits - 1) // d == 1
+ return n;
+ ++sr;
+ // 1 <= sr <= n_uword_bits - 1
+ // Not a special case
+ q = n << (n_uword_bits - sr);
+ r = n >> sr;
+ su_int carry = 0;
+ for (; sr > 0; --sr)
+ {
+ // r:q = ((r:q) << 1) | carry
+ r = (r << 1) | (q >> (n_uword_bits - 1));
+ q = (q << 1) | carry;
+ // carry = 0;
+ // if (r.all >= d.all)
+ // {
+ // r.all -= d.all;
+ // carry = 1;
+ // }
+ const si_int s = (si_int)(d - r - 1) >> (n_uword_bits - 1);
+ carry = s & 1;
+ r -= d & s;
+ }
+ q = (q << 1) | carry;
+ return q;
+}