1 /* lround() - S390 version.
2 Copyright (C) 2019-2022 Free Software Foundation, Inc.
3
4 This file is part of the GNU C Library.
5
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public License as
8 published by the Free Software Foundation; either version 2.1 of the
9 License, or (at your option) any later version.
10
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, see
18 <https://www.gnu.org/licenses/>. */
19
20 #ifdef HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT
21 # include <math.h>
22 # include <libm-alias-double.h>
23
24 /* The sizeof (long int) differs between s390x (8byte) and s390 (4byte).
25 Thus we need different instructions as the target size is encoded there.
26 Note: On s390 this instruction is only used if build with -mzarch. */
27 # ifdef __s390x__
28 # define INSN "cgdbra"
29 # else
30 # define INSN "cfdbra"
31 # endif
32
33 long int
__lround(double x)34 __lround (double x)
35 {
36 long int y;
37 /* The z196 zarch "convert to fixed" (cgdbra) instruction is rounding
38 x to the nearest integer with "ties away from 0" rounding mode
39 (M3-field: 1) where inexact exceptions are suppressed (M4-field: 4). */
40 __asm__ (INSN " %0,1,%1,4" : "=d" (y) : "f" (x) : "cc");
41 return y;
42 }
43 libm_alias_double (__lround, lround)
44
45 #else
46 # include <sysdeps/ieee754/dbl-64/s_lround.c>
47 #endif
48