[unsigned] int -> float soft-float conversions for single- and double-precision
git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@107535 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/floatunssidf.c b/lib/floatunssidf.c
new file mode 100644
index 0000000..c934405
--- /dev/null
+++ b/lib/floatunssidf.c
@@ -0,0 +1,45 @@
+//===-- lib/floatunssidf.c - uint -> double-precision conversion --*- C -*-===//
+//
+// The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements unsigned integer to double-precision conversion for the
+// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
+// mode.
+//
+//===----------------------------------------------------------------------===//
+
+#define DOUBLE_PRECISION
+#include "fp_lib.h"
+
+fp_t __floatunssidf(unsigned int a) {
+
+ const int aWidth = sizeof a * CHAR_BIT;
+
+ // Handle zero as a special case to protect clz
+ if (a == 0) return fromRep(0);
+
+ // Exponent of (fp_t)a is the width of abs(a).
+ const int exponent = (aWidth - 1) - __builtin_clz(a);
+ rep_t result;
+
+ // Shift a into the significand field, rounding if it is a right-shift
+ if (exponent <= significandBits) {
+ const int shift = significandBits - exponent;
+ result = (rep_t)a << shift ^ implicitBit;
+ } else {
+ const int shift = exponent - significandBits;
+ result = (rep_t)a >> shift ^ implicitBit;
+ rep_t round = (rep_t)a << (typeWidth - shift);
+ if (round > signBit) result++;
+ if (round == signBit) result += result & 1;
+ }
+
+ // Insert the exponent
+ result += (rep_t)(exponent + exponentBias) << significandBits;
+ return fromRep(result);
+}