1 /* ===-- fixdfti.c - Implement __fixdfti -----------------------------------=== 2 * 3 * The LLVM Compiler Infrastructure 4 * 5 * This file is dual licensed under the MIT and the University of Illinois Open 6 * Source Licenses. See LICENSE.TXT for details. 7 * 8 * ===----------------------------------------------------------------------=== 9 * 10 * This file implements __fixdfti for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15 #include "int_lib.h" 16 17 #ifdef CRT_HAS_128BIT 18 19 /* Returns: convert a to a signed long long, rounding toward zero. */ 20 21 /* Assumption: double is a IEEE 64 bit floating point type 22 * su_int is a 32 bit integral type 23 * value in double is representable in ti_int (no range checking performed) 24 */ 25 26 /* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */ 27 28 COMPILER_RT_ABI ti_int __fixdfti(double a)29 __fixdfti(double a) 30 { 31 double_bits fb; 32 fb.f = a; 33 int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023; 34 if (e < 0) 35 return 0; 36 ti_int s = (si_int)(fb.u.s.high & 0x80000000) >> 31; 37 ti_int r = 0x0010000000000000uLL | (0x000FFFFFFFFFFFFFuLL & fb.u.all); 38 if (e > 52) 39 r <<= (e - 52); 40 else 41 r >>= (52 - e); 42 return (r ^ s) - s; 43 } 44 45 #endif /* CRT_HAS_128BIT */ 46