sysdeps/aarch64/fpu/s_lrint.c

   1 /* Copyright (C) 1996-2018 Free Software Foundation, Inc.
   2
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <http://www.gnu.org/licenses/>.  */
  18
  19 #include <math.h>
  20 #include <get-rounding-mode.h>
  21 #include <stdint.h>
  22 #include <math-barriers.h>
  23 #include <libm-alias-double.h>
  24
  25 # define IREG_SIZE 64
  26
  27 # ifdef __ILP32__
  28 #  define OREG_SIZE 32
  29 # else
  30 #  define OREG_SIZE 64
  31 # endif
  32
  33 # define IREGS "d"
  34
  35 #if OREG_SIZE == 32
  36 # define OREGS "w"
  37 #else
  38 # define OREGS "x"
  39 #endif
  40
  41
  42 long int
  43 __lrint (double x)
  44 {
  45
  46 #if IREG_SIZE == 64 && OREG_SIZE == 32
  47   long int result;
  48
  49   if (__builtin_fabs (x) > INT32_MAX)
  50     {
  51       /* Converting large values to a 32 bit int may cause the frintx/fcvtza
  52          sequence to set both FE_INVALID and FE_INEXACT.  To avoid this
  53          check the rounding mode and do a single instruction with the
  54          appropriate rounding mode.  */
  55
  56       switch (get_rounding_mode ())
  57         {
  58         case FE_TONEAREST:
  59           asm volatile ("fcvtns" "\t%" OREGS "0, %" IREGS "1"
  60                         : "=r" (result) : "w" (x));
  61           break;
  62         case FE_UPWARD:
  63           asm volatile ("fcvtps" "\t%" OREGS "0, %" IREGS "1"
  64                         : "=r" (result) : "w" (x));
  65           break;
  66         case FE_DOWNWARD:
  67           asm volatile ("fcvtms" "\t%" OREGS "0, %" IREGS "1"
  68                         : "=r" (result) : "w" (x));
  69           break;
  70         case FE_TOWARDZERO:
  71         default:
  72           asm volatile ("fcvtzs" "\t%" OREGS "0, %" IREGS "1"
  73                         : "=r" (result) : "w" (x));
  74         }
  75       return result;
  76     }
  77 #endif
  78
  79   double r =  __builtin_rint (x);
  80
  81   /* Prevent gcc from calling lrint directly when compiled with
  82      -fno-math-errno by inserting a barrier.  */
  83
  84   math_opt_barrier (r);
  85   return r;
  86 }
  87
  88 libm_alias_double (__lrint, lrint)