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      1      1.1  joerg /* ===-- floatundixf.c - Implement __floatundixf ---------------------------===
      2      1.1  joerg  *
      3      1.1  joerg  *                     The LLVM Compiler Infrastructure
      4      1.1  joerg  *
      5      1.1  joerg  * This file is dual licensed under the MIT and the University of Illinois Open
      6      1.1  joerg  * Source Licenses. See LICENSE.TXT for details.
      7      1.1  joerg  *
      8      1.1  joerg  * ===----------------------------------------------------------------------===
      9      1.1  joerg  *
     10      1.1  joerg  * This file implements __floatundixf for the compiler_rt library.
     11      1.1  joerg  *
     12      1.1  joerg  * ===----------------------------------------------------------------------===
     13      1.1  joerg  */
     14      1.1  joerg 
     15      1.1  joerg #if !_ARCH_PPC
     16      1.1  joerg 
     17      1.1  joerg #include "int_lib.h"
     18      1.1  joerg 
     19      1.1  joerg /* Returns: convert a to a long double, rounding toward even. */
     20      1.1  joerg 
     21      1.1  joerg /* Assumption: long double is a IEEE 80 bit floating point type padded to 128 bits
     22      1.1  joerg  *             du_int is a 64 bit integral type
     23      1.1  joerg  */
     24      1.1  joerg 
     25      1.1  joerg /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
     26      1.1  joerg  * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
     27      1.1  joerg  */
     28  1.1.1.2  joerg COMPILER_RT_ABI long double
     29      1.1  joerg __floatundixf(du_int a)
     30      1.1  joerg {
     31      1.1  joerg     if (a == 0)
     32      1.1  joerg         return 0.0;
     33      1.1  joerg     const unsigned N = sizeof(du_int) * CHAR_BIT;
     34      1.1  joerg     int clz = __builtin_clzll(a);
     35      1.1  joerg     int e = (N - 1) - clz ;    /* exponent */
     36      1.1  joerg     long_double_bits fb;
     37      1.1  joerg     fb.u.high.s.low = (e + 16383);              /* exponent */
     38      1.1  joerg     fb.u.low.all = a << clz;                   /* mantissa */
     39      1.1  joerg     return fb.f;
     40      1.1  joerg }
     41      1.1  joerg 
     42      1.1  joerg #endif /* _ARCH_PPC */
     43