1  /* lround() - S390 version.
       2     Copyright (C) 2019-2023 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
      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