text: //===-- floatdisf.c - Implement __floatdisf -------------------------------===//
  //
  // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
  // See https://llvm.org/LICENSE.txt for license information.
  // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
  //
  //===----------------------------------------------------------------------===//
  //
  // This file implements __floatdisf for the compiler_rt library.
  //
  //===----------------------------------------------------------------------===//
  
  // Returns: convert a to a float, rounding toward even.
  
  // Assumption: float is a IEEE 32 bit floating point type
  //             di_int is a 64 bit integral type
  
  // seee eeee emmm mmmm mmmm mmmm mmmm mmmm
  
  #include "int_lib.h"
  
  COMPILER_RT_ABI float __floatdisf(di_int a) {
    if (a == 0)
      return 0.0F;
    const unsigned N = sizeof(di_int) * CHAR_BIT;
    const di_int s = a >> (N - 1);
    a = (a ^ s) - s;
    int sd = N - __builtin_clzll(a); // number of significant digits
    int e = sd - 1;                  // exponent
    if (sd > FLT_MANT_DIG) {
      //  start:  0000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQxxxxxxxxxxxxxxxxxx
      //  finish: 000000000000000000000000000000000000001xxxxxxxxxxxxxxxxxxxxxxPQR
      //                                                12345678901234567890123456
      //  1 = msb 1 bit
      //  P = bit FLT_MANT_DIG-1 bits to the right of 1
      //  Q = bit FLT_MANT_DIG bits to the right of 1
      //  R = "or" of all bits to the right of Q
      switch (sd) {
      case FLT_MANT_DIG + 1:
        a <<= 1;
        break;
      case FLT_MANT_DIG + 2:
        break;
      default:
        a = ((du_int)a >> (sd - (FLT_MANT_DIG + 2))) |
            ((a & ((du_int)(-1) >> ((N + FLT_MANT_DIG + 2) - sd))) != 0);
      };
      // finish:
      a |= (a & 4) != 0; // Or P into R
      ++a;               // round - this step may add a significant bit
      a >>= 2;           // dump Q and R
      // a is now rounded to FLT_MANT_DIG or FLT_MANT_DIG+1 bits
      if (a & ((du_int)1 << FLT_MANT_DIG)) {
        a >>= 1;
        ++e;
      }
      // a is now rounded to FLT_MANT_DIG bits
    } else {
      a <<= (FLT_MANT_DIG - sd);
      // a is now rounded to FLT_MANT_DIG bits
    }
    float_bits fb;
    fb.u = ((su_int)s & 0x80000000) | // sign
           ((e + 127) << 23) |        // exponent
           ((su_int)a & 0x007FFFFF);  // mantissa
    return fb.f;
  }
  
  #if defined(__ARM_EABI__)
  #if defined(COMPILER_RT_ARMHF_TARGET)
  AEABI_RTABI float __aeabi_l2f(di_int a) { return __floatdisf(a); }
  #else
  COMPILER_RT_ALIAS(__floatdisf, __aeabi_l2f)
  #endif
  #endif
  