100a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger//===-- lib/floatsitf.c - integer -> quad-precision conversion ----*- C -*-===// 200a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// 300a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// The LLVM Compiler Infrastructure 400a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// 500a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// This file is dual licensed under the MIT and the University of Illinois Open 600a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// Source Licenses. See LICENSE.TXT for details. 700a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// 800a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger//===----------------------------------------------------------------------===// 900a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// 1000a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// This file implements integer to quad-precision conversion for the 1100a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even 1200a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// mode. 1300a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger// 1400a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger//===----------------------------------------------------------------------===// 1500a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 1600a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger#define QUAD_PRECISION 1700a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger#include "fp_lib.h" 1800a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 1900a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger#if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) 2000a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg SonnenbergerCOMPILER_RT_ABI fp_t __floatsitf(int a) { 2100a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 2200a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger const int aWidth = sizeof a * CHAR_BIT; 2300a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 2400a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger // Handle zero as a special case to protect clz 2500a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger if (a == 0) 2600a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger return fromRep(0); 2700a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 2800a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger // All other cases begin by extracting the sign and absolute value of a 2900a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger rep_t sign = 0; 3000a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger unsigned aAbs = (unsigned)a; 3100a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger if (a < 0) { 3200a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger sign = signBit; 3300a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger aAbs += 0x80000000; 3400a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger } 3500a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 3600a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger // Exponent of (fp_t)a is the width of abs(a). 3700a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger const int exponent = (aWidth - 1) - __builtin_clz(a); 3800a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger rep_t result; 3900a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 4000a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger // Shift a into the significand field and clear the implicit bit. Extra 4100a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger // cast to unsigned int is necessary to get the correct behavior for 4200a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger // the input INT_MIN. 4300a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger const int shift = significandBits - exponent; 4400a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger result = (rep_t)aAbs << shift ^ implicitBit; 4500a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 4600a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger // Insert the exponent 4700a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger result += (rep_t)(exponent + exponentBias) << significandBits; 4800a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger // Insert the sign bit and return 4900a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger return fromRep(result | sign); 5000a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger} 5100a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger 5200a7da1552bc8a69ccf529a831b4cd46853c77e9Joerg Sonnenberger#endif 53