1  /* llrint() - 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  #if defined __s390x__ && defined HAVE_S390_MIN_Z196_ZARCH_ASM_SUPPORT
      21  /* We only support s390x as on s390 a long long int refers to a register pair
      22     of two 4byte registers instead of a 8byte register which is produced by the
      23     instruction.
      24     Note: On s390 this instruction would only be used if build with -mzarch.  */
      25  # include <math.h>
      26  # include <libm-alias-double.h>
      27  
      28  long long int
      29  __llrint (double x)
      30  {
      31    long long int y;
      32    /* The z196 zarch "convert to fixed" (cgdbra) instruction is rounding
      33       according to current rounding mode (M3-field: 0).
      34       First convert x with suppressed inexact exception and check if the
      35       resulting value is beyond the target limits (indicated by cc=3;
      36       Note: a nan is also indicated by cc=3).
      37       If the resulting value is within the target limits, redo
      38       without suppressing the inexact exception.  */
      39    __asm__ ("cgdbra %0,0,%1,4 \n\t"
      40  	   "jo 1f \n\t"
      41  	   "cgdbra %0,0,%1,0 \n\t"
      42  	   "1:"
      43  	   : "=&d" (y) : "f" (x) : "cc");
      44    return y;
      45  }
      46  libm_alias_double (__llrint, llrint)
      47  
      48  #else
      49  # include <sysdeps/ieee754/dbl-64/s_llrint.c>
      50  #endif