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-rw-r--r--lib/builtins/floatunditf.c40
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diff --git a/lib/builtins/floatunditf.c b/lib/builtins/floatunditf.c
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+//===-- lib/floatunditf.c - uint -> quad-precision conversion -----*- C -*-===//
+//
+// 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 du_int to quad-precision conversion for the
+// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
+// mode.
+//
+//===----------------------------------------------------------------------===//
+
+#define QUAD_PRECISION
+#include "fp_lib.h"
+
+#if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT)
+COMPILER_RT_ABI fp_t __floatunditf(du_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_clzll(a);
+ rep_t result;
+
+ // Shift a into the significand field and clear the implicit bit.
+ const int shift = significandBits - exponent;
+ result = (rep_t)a << shift ^ implicitBit;
+
+ // Insert the exponent
+ result += (rep_t)(exponent + exponentBias) << significandBits;
+ return fromRep(result);
+}
+
+#endif