1 //===-- floatdixf.c - Implement __floatdixf -------------------------------===// 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 __floatdixf for the compiler_rt library. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #if !_ARCH_PPC 14 15 #include "int_lib.h" 16 17 // Returns: convert a to a long double, rounding toward even. 18 19 // Assumption: long double is a IEEE 80 bit floating point type padded to 128 20 // bits di_int is a 64 bit integral type 21 22 // gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee 23 // eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm 24 // mmmm mmmm mmmm 25 26 COMPILER_RT_ABI long double __floatdixf(di_int a) { 27 if (a == 0) 28 return 0.0; 29 const unsigned N = sizeof(di_int) * CHAR_BIT; 30 const di_int s = a >> (N - 1); 31 a = (a ^ s) - s; 32 int clz = __builtin_clzll(a); 33 int e = (N - 1) - clz; // exponent 34 long_double_bits fb; 35 fb.u.high.s.low = ((su_int)s & 0x00008000) | // sign 36 (e + 16383); // exponent 37 fb.u.low.all = a << clz; // mantissa 38 return fb.f; 39 } 40 41 #endif // !_ARCH_PPC 42