1 /* ===-- fixunsxfti.c - Implement __fixunsxfti -----------------------------=== 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 __fixunsxfti for the compiler_rt library. 11 * 12 * ===----------------------------------------------------------------------=== 13 */ 14 15 #if __x86_64 16 17 #include "int_lib.h" 18 19 /* Returns: convert a to a unsigned long long, rounding toward zero. 20 * Negative values all become zero. 21 */ 22 23 /* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes 24 * tu_int is a 64 bit integral type 25 * value in long double is representable in tu_int or is negative 26 * (no range checking performed) 27 */ 28 29 /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee | 30 * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm 31 */ 32 33 tu_int 34 __fixunsxfti(long double a) 35 { 36 long_double_bits fb; 37 fb.f = a; 38 int e = (fb.u.high.s.low & 0x00007FFF) - 16383; 39 if (e < 0 || (fb.u.high.s.low & 0x00008000)) 40 return 0; 41 tu_int r = fb.u.low.all; 42 if (e > 63) 43 r <<= (e - 63); 44 else 45 r >>= (63 - e); 46 return r; 47 } 48 49 #endif 50
