1 /* ix87 specific implementation of arctanh function.
2 Copyright (C) 1996, 1999, 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.
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.
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.
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/>. */
20 #include <machine/asm.h>
25 /* Please note that we use double values for 0.5 and 1.0. These
26 numbers have exact representations and so we don't get accuracy
27 problems. The advantage is that the code is simpler. */
30 ASM_SIZE_DIRECTIVE(half)
33 ASM_SIZE_DIRECTIVE(one)
34 /* It is not important that this constant is precise. It is only
35 a value which is known to be on the safe side for using the
36 fyl2xp1 instruction. */
39 ASM_SIZE_DIRECTIVE(limit)
42 ln2_2: .tfloat 0.3465735902799726547086160
43 ASM_SIZE_DIRECTIVE(ln2_2)
46 #define MO(op) op##@GOTOFF(%edx)
52 ENTRY(__ieee754_atanhl)
65 andl $0x8000, %ecx // ECX == 0 iff X >= 0
67 fldt MO(ln2_2) // 0.5*ln2
69 fldt 4(%esp) // |x| : 0.5*ln2
70 fcoml MO(half) // |x| : 0.5*ln2
71 fld %st(0) // |x| : |x| : 0.5*ln2
72 fnstsw // |x| : |x| : 0.5*ln2
75 fadd %st, %st(1) // |x| : 2*|x| : 0.5*ln2
76 fld %st // |x| : |x| : 2*|x| : 0.5*ln2
77 fsubrl MO(one) // 1-|x| : |x| : 2*|x| : 0.5*ln2
78 fxch // |x| : 1-|x| : 2*|x| : 0.5*ln2
79 fmul %st(2) // 2*|x|^2 : 1-|x| : 2*|x| : 0.5*ln2
80 fdivp // (2*|x|^2)/(1-|x|) : 2*|x| : 0.5*ln2
81 faddp // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
82 fcoml MO(limit) // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
83 fnstsw // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
86 fyl2xp1 // 0.5*ln2*ld(1+2*|x|+(2*|x|^2)/(1-|x|))
88 fchs // 0.5*ln2*ld(1+2*x+(2*x^2)/(1-x))
92 4: faddl MO(one) // 1+2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
93 fyl2x // 0.5*ln2*ld(1+2*|x|+(2*|x|^2)/(1-|x|))
95 fchs // 0.5*ln2*ld(1+2*x+(2*x^2)/(1-x))
99 2: faddl MO(one) // 1+|x| : |x| : 0.5*ln2
100 fxch // |x| : 1+|x| : 0.5*ln2
101 fsubrl MO(one) // 1-|x| : 1+|x| : 0.5*ln2
102 fdivrp // (1+|x|)/(1-|x|) : 0.5*ln2
103 fyl2x // 0.5*ln2*ld((1+|x|)/(1-|x|))
105 fchs // 0.5*ln2*ld((1+x)/(1-x))
109 5: cmpl $0x80000000, 8(%esp)
115 END(__ieee754_atanhl)
116 strong_alias (__ieee754_atanhl, __atanhl_finite)