1 //===-- fixxfdi.c - Implement __fixxfdi -----------------------------------===// 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 __fixxfdi 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 signed long long, rounding toward zero. 18 19 // Assumption: long double is an intel 80 bit floating point type padded with 6 20 // bytes di_int is a 64 bit integral type value in long double is representable 21 // in di_int (no range checking performed) 22 23 // gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee 24 // eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm 25 // mmmm mmmm mmmm 26 27 #if defined(_MSC_VER) && !defined(__clang__) 28 // MSVC throws a warning about 'uninitialized variable use' here, 29 // disable it for builds that warn-as-error 30 #pragma warning(push) 31 #pragma warning(disable : 4700) 32 #endif 33 34 COMPILER_RT_ABI di_int __fixxfdi(long double a) { 35 const di_int di_max = (di_int)((~(du_int)0) / 2); 36 const di_int di_min = -di_max - 1; 37 long_double_bits fb; 38 fb.f = a; 39 int e = (fb.u.high.s.low & 0x00007FFF) - 16383; 40 if (e < 0) 41 return 0; 42 if ((unsigned)e >= sizeof(di_int) * CHAR_BIT) 43 return a > 0 ? di_max : di_min; 44 di_int s = -(si_int)((fb.u.high.s.low & 0x00008000) >> 15); 45 di_int r = fb.u.low.all; 46 r = (du_int)r >> (63 - e); 47 return (r ^ s) - s; 48 } 49 50 #if defined(_MSC_VER) && !defined(__clang__) 51 #pragma warning(pop) 52 #endif 53 54 #endif // !_ARCH_PPC 55