1 //===-- lib/floatsitf.c - integer -> quad-precision conversion ----*- C -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 // 9 // This file implements integer to quad-precision conversion for the 10 // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even 11 // mode. 12 // 13 //===----------------------------------------------------------------------===// 14 15 #define QUAD_PRECISION 16 #include "fp_lib.h" 17 18 #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) __floatsitf(int a)19COMPILER_RT_ABI fp_t __floatsitf(int a) { 20 21 const int aWidth = sizeof a * CHAR_BIT; 22 23 // Handle zero as a special case to protect clz 24 if (a == 0) 25 return fromRep(0); 26 27 // All other cases begin by extracting the sign and absolute value of a 28 rep_t sign = 0; 29 unsigned aAbs = (unsigned)a; 30 if (a < 0) { 31 sign = signBit; 32 aAbs = ~(unsigned)a + 1U; 33 } 34 35 // Exponent of (fp_t)a is the width of abs(a). 36 const int exponent = (aWidth - 1) - __builtin_clz(aAbs); 37 rep_t result; 38 39 // Shift a into the significand field and clear the implicit bit. 40 const int shift = significandBits - exponent; 41 result = (rep_t)aAbs << shift ^ implicitBit; 42 43 // Insert the exponent 44 result += (rep_t)(exponent + exponentBias) << significandBits; 45 // Insert the sign bit and return 46 return fromRep(result | sign); 47 } 48 49 #endif 50