1 //===-- fixunsxfti.c - Implement __fixunsxfti -----------------------------===// 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 __fixunsxfti for the compiler_rt library. 10 // 11 //===----------------------------------------------------------------------===// 12 13 #include "int_lib.h" 14 15 #ifdef CRT_HAS_128BIT 16 17 // Returns: convert a to a unsigned long long, rounding toward zero. 18 // Negative values all become zero. 19 20 // Assumption: long double is an intel 80 bit floating point type padded with 6 21 // bytes tu_int is a 128 bit integral type value in long double is representable 22 // in tu_int or is negative 23 24 // gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee 25 // eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm 26 // mmmm mmmm mmmm 27 28 COMPILER_RT_ABI tu_int __fixunsxfti(long double a) { 29 long_double_bits fb; 30 fb.f = a; 31 int e = (fb.u.high.s.low & 0x00007FFF) - 16383; 32 if (e < 0 || (fb.u.high.s.low & 0x00008000)) 33 return 0; 34 if ((unsigned)e > sizeof(tu_int) * CHAR_BIT) 35 return ~(tu_int)0; 36 tu_int r = fb.u.low.all; 37 if (e > 63) 38 r <<= (e - 63); 39 else 40 r >>= (63 - e); 41 return r; 42 } 43 44 #endif // CRT_HAS_128BIT 45