1*0b57cec5SDimitry Andric //===-- lib/floatsitf.c - integer -> quad-precision conversion ----*- C -*-===// 2*0b57cec5SDimitry Andric // 3*0b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4*0b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information. 5*0b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6*0b57cec5SDimitry Andric // 7*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 8*0b57cec5SDimitry Andric // 9*0b57cec5SDimitry Andric // This file implements integer to quad-precision conversion for the 10*0b57cec5SDimitry Andric // compiler-rt library in the IEEE-754 default round-to-nearest, ties-to-even 11*0b57cec5SDimitry Andric // mode. 12*0b57cec5SDimitry Andric // 13*0b57cec5SDimitry Andric //===----------------------------------------------------------------------===// 14*0b57cec5SDimitry Andric 15*0b57cec5SDimitry Andric #define QUAD_PRECISION 16*0b57cec5SDimitry Andric #include "fp_lib.h" 17*0b57cec5SDimitry Andric 18*0b57cec5SDimitry Andric #if defined(CRT_HAS_128BIT) && defined(CRT_LDBL_128BIT) 19*0b57cec5SDimitry Andric COMPILER_RT_ABI fp_t __floatsitf(int a) { 20*0b57cec5SDimitry Andric 21*0b57cec5SDimitry Andric const int aWidth = sizeof a * CHAR_BIT; 22*0b57cec5SDimitry Andric 23*0b57cec5SDimitry Andric // Handle zero as a special case to protect clz 24*0b57cec5SDimitry Andric if (a == 0) 25*0b57cec5SDimitry Andric return fromRep(0); 26*0b57cec5SDimitry Andric 27*0b57cec5SDimitry Andric // All other cases begin by extracting the sign and absolute value of a 28*0b57cec5SDimitry Andric rep_t sign = 0; 29*0b57cec5SDimitry Andric unsigned aAbs = (unsigned)a; 30*0b57cec5SDimitry Andric if (a < 0) { 31*0b57cec5SDimitry Andric sign = signBit; 32*0b57cec5SDimitry Andric aAbs = ~(unsigned)a + 1U; 33*0b57cec5SDimitry Andric } 34*0b57cec5SDimitry Andric 35*0b57cec5SDimitry Andric // Exponent of (fp_t)a is the width of abs(a). 36*0b57cec5SDimitry Andric const int exponent = (aWidth - 1) - __builtin_clz(aAbs); 37*0b57cec5SDimitry Andric rep_t result; 38*0b57cec5SDimitry Andric 39*0b57cec5SDimitry Andric // Shift a into the significand field and clear the implicit bit. 40*0b57cec5SDimitry Andric const int shift = significandBits - exponent; 41*0b57cec5SDimitry Andric result = (rep_t)aAbs << shift ^ implicitBit; 42*0b57cec5SDimitry Andric 43*0b57cec5SDimitry Andric // Insert the exponent 44*0b57cec5SDimitry Andric result += (rep_t)(exponent + exponentBias) << significandBits; 45*0b57cec5SDimitry Andric // Insert the sign bit and return 46*0b57cec5SDimitry Andric return fromRep(result | sign); 47*0b57cec5SDimitry Andric } 48*0b57cec5SDimitry Andric 49*0b57cec5SDimitry Andric #endif 50