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      1 //===-- lib/fixsfsi.c - Single-precision -> integer conversion ----*- C -*-===//
      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 single-precision to integer conversion for the
     11 // compiler-rt library.  No range checking is performed; the behavior of this
     12 // conversion is undefined for out of range values in the C standard.
     13 //
     14 //===----------------------------------------------------------------------===//
     15 
     16 #define SINGLE_PRECISION
     17 #include "fp_lib.h"
     18 
     19 ARM_EABI_FNALIAS(f2iz, fixsfsi);
     20 
     21 COMPILER_RT_ABI int
     22 __fixsfsi(fp_t a) {
     23     // Break a into sign, exponent, significand
     24     const rep_t aRep = toRep(a);
     25     const rep_t aAbs = aRep & absMask;
     26     const int sign = aRep & signBit ? -1 : 1;
     27     const int exponent = (aAbs >> significandBits) - exponentBias;
     28     const rep_t significand = (aAbs & significandMask) | implicitBit;
     29 
     30     // If 0 < exponent < significandBits, right shift to get the result.
     31     if ((unsigned int)exponent < significandBits) {
     32         return sign * (significand >> (significandBits - exponent));
     33     }
     34 
     35     // If exponent is negative, the result is zero.
     36     else if (exponent < 0) {
     37         return 0;
     38     }
     39 
     40     // If significandBits < exponent, left shift to get the result.  This shift
     41     // may end up being larger than the type width, which incurs undefined
     42     // behavior, but the conversion itself is undefined in that case, so
     43     // whatever the compiler decides to do is fine.
     44     else {
     45         return sign * (significand << (exponent - significandBits));
     46     }
     47 }
     48