1 /* ===-- fixunsdfti.c - Implement __fixunsdfti -----------------------------=== 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 __fixunsdfti for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15 #include "int_lib.h" 16 17 #if __x86_64 18 19 /* Returns: convert a to a unsigned long long, rounding toward zero. 20 * Negative values all become zero. 21 */ 22 23 /* Assumption: double is a IEEE 64 bit floating point type 24 * tu_int is a 64 bit integral type 25 * value in double is representable in tu_int or is negative 26 * (no range checking performed) 27 */ 28 29 /* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */ 30 31 tu_int 32 __fixunsdfti(double a) 33 { 34 double_bits fb; 35 fb.f = a; 36 int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023; 37 if (e < 0 || (fb.u.s.high & 0x80000000)) 38 return 0; 39 tu_int r = 0x0010000000000000uLL | (fb.u.all & 0x000FFFFFFFFFFFFFuLL); 40 if (e > 52) 41 r <<= (e - 52); 42 else 43 r >>= (52 - e); 44 return r; 45 } 46 47 #endif 48
