sysdeps/i386/fpu/e_atanhf.S

   1 /* ix87 specific implementation of arctanh function.
   2    Copyright (C) 1996, 1999, 2005, 2011-2012 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
   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
   8    License as published by the Free Software Foundation; either
   9    version 2.1 of the 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    <http://www.gnu.org/licenses/>.  */
  19
  20 #include <machine/asm.h>
  21
  22         .section .rodata
  23
  24         .align ALIGNARG(4)
  25         ASM_TYPE_DIRECTIVE(half,@object)
  26 half:   .double 0.5
  27         ASM_SIZE_DIRECTIVE(half)
  28         ASM_TYPE_DIRECTIVE(one,@object)
  29 one:    .double 1.0
  30         ASM_SIZE_DIRECTIVE(one)
  31         ASM_TYPE_DIRECTIVE(limit,@object)
  32 limit:  .double 0.29
  33         ASM_SIZE_DIRECTIVE(limit)
  34         .align ALIGNARG(4)
  35         ASM_TYPE_DIRECTIVE(ln2_2,@object)
  36 ln2_2:  .tfloat 0.3465735902799726547086160
  37         ASM_SIZE_DIRECTIVE(ln2_2)
  38
  39 #ifdef PIC
  40 #define MO(op) op##@GOTOFF(%edx)
  41 #else
  42 #define MO(op) op
  43 #endif
  44
  45         .text
  46 ENTRY(__ieee754_atanhf)
  47         movl    4(%esp), %ecx
  48
  49         movl    %ecx, %eax
  50         andl    $0x7fffffff, %eax
  51         cmpl    $0x7f800000, %eax
  52         ja      5f
  53
  54 #ifdef PIC
  55         LOAD_PIC_REG (dx)
  56 #endif
  57
  58         andl    $0x80000000, %ecx // ECX == 0 iff X >= 0
  59
  60         fldt    MO(ln2_2)       // 0.5*ln2
  61         xorl    %ecx, 4(%esp)
  62         flds    4(%esp)         // |x| : 0.5*ln2
  63         fcoml   MO(half)        // |x| : 0.5*ln2
  64         fld     %st(0)          // |x| : |x| : 0.5*ln2
  65         fnstsw                  // |x| : |x| : 0.5*ln2
  66         sahf
  67         jae     2f
  68         fadd    %st, %st(1)     // |x| : 2*|x| : 0.5*ln2
  69         fld     %st             // |x| : |x| : 2*|x| : 0.5*ln2
  70         fsubrl  MO(one)         // 1-|x| : |x| : 2*|x| : 0.5*ln2
  71         fxch                    // |x| : 1-|x| : 2*|x| : 0.5*ln2
  72         fmul    %st(2)          // 2*|x|^2 : 1-|x| : 2*|x| : 0.5*ln2
  73         fdivp                   // (2*|x|^2)/(1-|x|) : 2*|x| : 0.5*ln2
  74         faddp                   // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
  75         fcoml   MO(limit)       // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
  76         fnstsw                  // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
  77         sahf
  78         jae     4f
  79         fyl2xp1                 // 0.5*ln2*ld(1+2*|x|+(2*|x|^2)/(1-|x|))
  80         jecxz   3f
  81         fchs                    // 0.5*ln2*ld(1+2*x+(2*x^2)/(1-x))
  82 3:      ret
  83
  84         .align ALIGNARG(4)
  85 4:      faddl   MO(one)         // 1+2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
  86         fyl2x                   // 0.5*ln2*ld(1+2*|x|+(2*|x|^2)/(1-|x|))
  87         jecxz   3f
  88         fchs                    // 0.5*ln2*ld(1+2*x+(2*x^2)/(1-x))
  89 3:      ret
  90
  91         .align ALIGNARG(4)
  92 2:      faddl   MO(one)         // 1+|x| : |x| : 0.5*ln2
  93         fxch                    // |x| : 1+|x| : 0.5*ln2
  94         fsubrl  MO(one)         // 1-|x| : 1+|x| : 0.5*ln2
  95         fdivrp                  // (1+|x|)/(1-|x|) : 0.5*ln2
  96         fyl2x                   // 0.5*ln2*ld((1+|x|)/(1-|x|))
  97         jecxz   3f
  98         fchs                    // 0.5*ln2*ld((1+x)/(1-x))
  99 3:      ret
 100
 101         // x == NaN
 102 5:      flds    4(%esp)
 103         ret
 104 END(__ieee754_atanhf)
 105 strong_alias (__ieee754_atanhf, __atanhf_finite)