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 float to integer conversion for the 11 // compiler-rt library. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #include "fp_lib.h" 16 17 static __inline fixint_t __fixint(fp_t a) { 18 const fixint_t fixint_max = (fixint_t)((~(fixuint_t)0) / 2); 19 const fixint_t fixint_min = -fixint_max - 1; 20 // Break a into sign, exponent, significand 21 const rep_t aRep = toRep(a); 22 const rep_t aAbs = aRep & absMask; 23 const fixint_t sign = aRep & signBit ? -1 : 1; 24 const int exponent = (aAbs >> significandBits) - exponentBias; 25 const rep_t significand = (aAbs & significandMask) | implicitBit; 26 27 // If exponent is negative, the result is zero. 28 if (exponent < 0) 29 return 0; 30 31 // If the value is too large for the integer type, saturate. 32 if ((unsigned)exponent >= sizeof(fixint_t) * CHAR_BIT) 33 return sign == 1 ? fixint_max : fixint_min; 34 35 // If 0 <= exponent < significandBits, right shift to get the result. 36 // Otherwise, shift left. 37 if (exponent < significandBits) 38 return sign * (significand >> (significandBits - exponent)); 39 else 40 return sign * ((fixint_t)significand << (exponent - significandBits)); 41 } 42
