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      1 /* ===-- floatundixf.c - Implement __floatundixf ---------------------------===
      2  *
      3  *                     The LLVM Compiler Infrastructure
      4  *
      5  * This file is dual licensed under the MIT and the University of Illinois Open
      6  * Source Licenses. See LICENSE.TXT for details.
      7  *
      8  * ===----------------------------------------------------------------------===
      9  *
     10  * This file implements __floatundixf for the compiler_rt library.
     11  *
     12  * ===----------------------------------------------------------------------===
     13  */
     14 
     15 #if !_ARCH_PPC
     16 
     17 #include "int_lib.h"
     18 
     19 /* Returns: convert a to a long double, rounding toward even. */
     20 
     21 /* Assumption: long double is a IEEE 80 bit floating point type padded to 128 bits
     22  *             du_int is a 64 bit integral type
     23  */
     24 
     25 /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
     26  * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
     27  */
     28 COMPILER_RT_ABI long double
     29 __floatundixf(du_int a)
     30 {
     31     if (a == 0)
     32         return 0.0;
     33     const unsigned N = sizeof(du_int) * CHAR_BIT;
     34     int clz = __builtin_clzll(a);
     35     int e = (N - 1) - clz ;    /* exponent */
     36     long_double_bits fb;
     37     fb.u.high.s.low = (e + 16383);              /* exponent */
     38     fb.u.low.all = a << clz;                   /* mantissa */
     39     return fb.f;
     40 }
     41 
     42 #endif /* _ARCH_PPC */
     43