xref: /netbsd-src/sys/external/bsd/compiler_rt/dist/lib/builtins/fixunsxfdi.c (revision ef84fd3bd8895f4e6be1e38baf19e6dc3255bc64)
1156cd587Sjoerg /* ===-- fixunsxfdi.c - Implement __fixunsxfdi -----------------------------===
2156cd587Sjoerg  *
3156cd587Sjoerg  *                     The LLVM Compiler Infrastructure
4156cd587Sjoerg  *
5156cd587Sjoerg  * This file is dual licensed under the MIT and the University of Illinois Open
6156cd587Sjoerg  * Source Licenses. See LICENSE.TXT for details.
7156cd587Sjoerg  *
8156cd587Sjoerg  * ===----------------------------------------------------------------------===
9156cd587Sjoerg  *
10156cd587Sjoerg  * This file implements __fixunsxfdi for the compiler_rt library.
11156cd587Sjoerg  *
12156cd587Sjoerg  * ===----------------------------------------------------------------------===
13156cd587Sjoerg  */
14156cd587Sjoerg 
15156cd587Sjoerg #if !_ARCH_PPC
16156cd587Sjoerg 
17156cd587Sjoerg #include "int_lib.h"
18156cd587Sjoerg 
19156cd587Sjoerg /* Returns: convert a to a unsigned long long, rounding toward zero.
20156cd587Sjoerg  *          Negative values all become zero.
21156cd587Sjoerg  */
22156cd587Sjoerg 
23156cd587Sjoerg /* Assumption: long double is an intel 80 bit floating point type padded with 6 bytes
24156cd587Sjoerg  *             du_int is a 64 bit integral type
25156cd587Sjoerg  *             value in long double is representable in du_int or is negative
26156cd587Sjoerg  *                 (no range checking performed)
27156cd587Sjoerg  */
28156cd587Sjoerg 
29156cd587Sjoerg /* gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee eeee |
30156cd587Sjoerg  * 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm
31156cd587Sjoerg  */
32156cd587Sjoerg 
33f7f78b33Sjoerg COMPILER_RT_ABI du_int
__fixunsxfdi(long double a)34156cd587Sjoerg __fixunsxfdi(long double a)
35156cd587Sjoerg {
36156cd587Sjoerg     long_double_bits fb;
37156cd587Sjoerg     fb.f = a;
38156cd587Sjoerg     int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
39156cd587Sjoerg     if (e < 0 || (fb.u.high.s.low & 0x00008000))
40156cd587Sjoerg         return 0;
41*ef84fd3bSjoerg     if ((unsigned)e > sizeof(du_int) * CHAR_BIT)
42*ef84fd3bSjoerg         return ~(du_int)0;
43156cd587Sjoerg     return fb.u.low.all >> (63 - e);
44156cd587Sjoerg }
45156cd587Sjoerg 
46156cd587Sjoerg #endif
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