fixunsdfdi.c revision 214152
1214152Sed/* ===-- fixunsdfdi.c - Implement __fixunsdfdi -----------------------------=== 2214152Sed * 3214152Sed * The LLVM Compiler Infrastructure 4214152Sed * 5214152Sed * This file is distributed under the University of Illinois Open Source 6214152Sed * License. See LICENSE.TXT for details. 7214152Sed * 8214152Sed * ===----------------------------------------------------------------------=== 9214152Sed * 10214152Sed * This file implements __fixunsdfdi for the compiler_rt library. 11214152Sed * 12214152Sed * ===----------------------------------------------------------------------=== 13214152Sed */ 14214152Sed 15214152Sed#include "int_lib.h" 16214152Sed 17214152Sed/* Returns: convert a to a unsigned long long, rounding toward zero. 18214152Sed * Negative values all become zero. 19214152Sed */ 20214152Sed 21214152Sed/* Assumption: double is a IEEE 64 bit floating point type 22214152Sed * du_int is a 64 bit integral type 23214152Sed * value in double is representable in du_int or is negative 24214152Sed * (no range checking performed) 25214152Sed */ 26214152Sed 27214152Sed/* seee eeee eeee mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm */ 28214152Sed 29214152Seddu_int 30214152Sed__fixunsdfdi(double a) 31214152Sed{ 32214152Sed double_bits fb; 33214152Sed fb.f = a; 34214152Sed int e = ((fb.u.s.high & 0x7FF00000) >> 20) - 1023; 35214152Sed if (e < 0 || (fb.u.s.high & 0x80000000)) 36214152Sed return 0; 37214152Sed udwords r; 38214152Sed r.s.high = (fb.u.s.high & 0x000FFFFF) | 0x00100000; 39214152Sed r.s.low = fb.u.s.low; 40214152Sed if (e > 52) 41214152Sed r.all <<= (e - 52); 42214152Sed else 43214152Sed r.all >>= (52 - e); 44214152Sed return r.all; 45214152Sed} 46