1  /* lrint() - 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  __lrint (double x)
      35  {
      36    long int y;
      37    /* The z196 zarch "convert to fixed" (cgdbra) instruction is rounding
      38       according to current rounding mode (M3-field: 0).
      39       First convert x with suppressed inexact exception and check if the
      40       resulting value is beyond the target limits (indicated by cc=3;
      41       Note: a nan is also indicated by cc=3).
      42       If the resulting value is within the target limits, redo
      43       without suppressing the inexact exception.  */
      44    __asm__ (INSN " %0,0,%1,4 \n\t"
      45  	   "jo 1f \n\t"
      46  	   INSN " %0,0,%1,0 \n\t"
      47  	   "1:"
      48  	   : "=&d" (y) : "f" (x) : "cc");
      49    return y;
      50  }
      51  libm_alias_double (__lrint, lrint)
      52  
      53  #else
      54  # include <sysdeps/ieee754/dbl-64/s_lrint.c>
      55  #endif