1 //===-- lib/floatunditf.c - uint -> quad-precision 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 du_int to quad-precision conversion for the 11 // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even 12 // mode. 13 // 14 //===----------------------------------------------------------------------===// 15 16 #define QUAD_PRECISION 17 #include "fp_lib.h" 18 19 #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) 20 COMPILER_RT_ABI fp_t __floatunditf(du_int a) { 21 22 const int aWidth = sizeof a * CHAR_BIT; 23 24 // Handle zero as a special case to protect clz 25 if (a == 0) return fromRep(0); 26 27 // Exponent of (fp_t)a is the width of abs(a). 28 const int exponent = (aWidth - 1) - __builtin_clzll(a); 29 rep_t result; 30 31 // Shift a into the significand field and clear the implicit bit. 32 const int shift = significandBits - exponent; 33 result = (rep_t)a << shift ^ implicitBit; 34 35 // Insert the exponent 36 result += (rep_t)(exponent + exponentBias) << significandBits; 37 return fromRep(result); 38 } 39 40 #endif 41
