1 //===-- lib/floatunsidf.c - uint -> double-precision conversion ---*- C -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is dual licensed under the MIT and the University of Illinois Open
6 // Source Licenses. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements unsigned integer to double-precision conversion for the
11 // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even
14 //===----------------------------------------------------------------------===//
16 #define DOUBLE_PRECISION
22 __floatunsidf(unsigned int a) {
24 const int aWidth = sizeof a * CHAR_BIT;
26 // Handle zero as a special case to protect clz
27 if (a == 0) return fromRep(0);
29 // Exponent of (fp_t)a is the width of abs(a).
30 const int exponent = (aWidth - 1) - __builtin_clz(a);
33 // Shift a into the significand field and clear the implicit bit.
34 const int shift = significandBits - exponent;
35 result = (rep_t)a << shift ^ implicitBit;
37 // Insert the exponent
38 result += (rep_t)(exponent + exponentBias) << significandBits;
39 return fromRep(result);
42 #if defined(__ARM_EABI__)
43 AEABI_RTABI fp_t __aeabi_ui2d(unsigned int a) {
44 return __floatunsidf(a);