xref: /freebsd/contrib/llvm-project/compiler-rt/lib/builtins/fixunsxfti.c (revision 5f757f3ff9144b609b3c433dfd370cc6bdc191ad)
10b57cec5SDimitry Andric //===-- fixunsxfti.c - Implement __fixunsxfti -----------------------------===//
20b57cec5SDimitry Andric //
30b57cec5SDimitry Andric // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
40b57cec5SDimitry Andric // See https://llvm.org/LICENSE.txt for license information.
50b57cec5SDimitry Andric // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
60b57cec5SDimitry Andric //
70b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
80b57cec5SDimitry Andric //
90b57cec5SDimitry Andric // This file implements __fixunsxfti for the compiler_rt library.
100b57cec5SDimitry Andric //
110b57cec5SDimitry Andric //===----------------------------------------------------------------------===//
120b57cec5SDimitry Andric 
130b57cec5SDimitry Andric #include "int_lib.h"
140b57cec5SDimitry Andric 
150b57cec5SDimitry Andric #ifdef CRT_HAS_128BIT
160b57cec5SDimitry Andric 
170b57cec5SDimitry Andric // Returns: convert a to a unsigned long long, rounding toward zero.
180b57cec5SDimitry Andric //          Negative values all become zero.
190b57cec5SDimitry Andric 
200b57cec5SDimitry Andric // Assumption: long double is an intel 80 bit floating point type padded with 6
210b57cec5SDimitry Andric // bytes tu_int is a 128 bit integral type value in long double is representable
220b57cec5SDimitry Andric // in tu_int or is negative
230b57cec5SDimitry Andric 
240b57cec5SDimitry Andric // gggg gggg gggg gggg gggg gggg gggg gggg | gggg gggg gggg gggg seee eeee eeee
250b57cec5SDimitry Andric // eeee | 1mmm mmmm mmmm mmmm mmmm mmmm mmmm mmmm | mmmm mmmm mmmm mmmm mmmm
260b57cec5SDimitry Andric // mmmm mmmm mmmm
270b57cec5SDimitry Andric 
28*5f757f3fSDimitry Andric COMPILER_RT_ABI tu_int __fixunsxfti(xf_float a) {
29*5f757f3fSDimitry Andric   xf_bits fb;
300b57cec5SDimitry Andric   fb.f = a;
310b57cec5SDimitry Andric   int e = (fb.u.high.s.low & 0x00007FFF) - 16383;
320b57cec5SDimitry Andric   if (e < 0 || (fb.u.high.s.low & 0x00008000))
330b57cec5SDimitry Andric     return 0;
340b57cec5SDimitry Andric   if ((unsigned)e > sizeof(tu_int) * CHAR_BIT)
350b57cec5SDimitry Andric     return ~(tu_int)0;
360b57cec5SDimitry Andric   tu_int r = fb.u.low.all;
370b57cec5SDimitry Andric   if (e > 63)
380b57cec5SDimitry Andric     r <<= (e - 63);
390b57cec5SDimitry Andric   else
400b57cec5SDimitry Andric     r >>= (63 - e);
410b57cec5SDimitry Andric   return r;
420b57cec5SDimitry Andric }
430b57cec5SDimitry Andric 
440b57cec5SDimitry Andric #endif // CRT_HAS_128BIT
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