1 //===-- lib/fixdfsi.c - Double-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 double-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 DOUBLE_PRECISION 17 #include "fp_lib.h" 18 19 #include "int_lib.h" 20 21 ARM_EABI_FNALIAS(d2iz, fixdfsi) 22 23 COMPILER_RT_ABI int 24 __fixdfsi(fp_t a) { 25 26 // Break a into sign, exponent, significand 27 const rep_t aRep = toRep(a); 28 const rep_t aAbs = aRep & absMask; 29 const int sign = aRep & signBit ? -1 : 1; 30 const int exponent = (aAbs >> significandBits) - exponentBias; 31 const rep_t significand = (aAbs & significandMask) | implicitBit; 32 33 // If 0 < exponent < significandBits, right shift to get the result. 34 if ((unsigned int)exponent < significandBits) { 35 return sign * (significand >> (significandBits - exponent)); 36 } 37 38 // If exponent is negative, the result is zero. 39 else if (exponent < 0) { 40 return 0; 41 } 42 43 // If significandBits < exponent, left shift to get the result. This shift 44 // may end up being larger than the type width, which incurs undefined 45 // behavior, but the conversion itself is undefined in that case, so 46 // whatever the compiler decides to do is fine. 47 else { 48 return sign * (significand << (exponent - significandBits)); 49 } 50 } 51
