1 /* ===-- fixunsdfdi.c - Implement __fixunsdfdi -----------------------------=== 2 * 3 * The LLVM Compiler Infrastructure 4 * 5 * This file is distributed under the University of Illinois Open Source 6 * License. See LICENSE.TXT for details. 7 * 8 * ===----------------------------------------------------------------------=== 9 * 10 * This file implements __fixunsdfdi for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15 #include "int_lib.h" 16 17 /* Returns: convert a to a unsigned long long, rounding toward zero. 18 * Negative values all become zero. 19 */ 20 21 /* Assumption: double is a IEEE 64 bit floating point type 22 * du_int is a 64 bit integral type 23 * value in double is representable in du_int or is negative 24 * (no range checking performed) 25 */ 26 27 /* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */ 28 29 du_int 30 __fixunsdfdi(double a) 31 { 32 double_bits fb; 33 fb.f = a; 34 int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023; 35 if (e < 0 || (fb.u.s.high & 0x80000000)) 36 return 0; 37 udwords r; 38 r.s.high = (fb.u.s.high & 0x000FFFFF) | 0x00100000; 39 r.s.low = fb.u.s.low; 40 if (e > 52) 41 r.all <<= (e - 52); 42 else 43 r.all >>= (52 - e); 44 return r.all; 45 } 46
