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109 lines
3.2 KiB
ArmAsm
109 lines
3.2 KiB
ArmAsm
/* ix87 specific implementation of arctanh function.
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Copyright (C) 1996 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If not,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <machine/asm.h>
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#ifdef __ELF__
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.section .rodata
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#else
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.text
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#endif
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.align ALIGNARG(4)
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/* Please note that we use double values for 0.5 and 1.0. These
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numbers have exact representations and so we don't get accuracy
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problems. The advantage is that the code is simpler. */
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ASM_TYPE_DIRECTIVE(half,@object)
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half: .double 0.5
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ASM_SIZE_DIRECTIVE(half)
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ASM_TYPE_DIRECTIVE(one,@object)
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one: .double 1.0
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ASM_SIZE_DIRECTIVE(one)
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/* It is not important that this constant is precise. It is only
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a value which is known to be on the safe side for using the
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fyl2xp1 instruction. */
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ASM_TYPE_DIRECTIVE(limit,@object)
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limit: .double 0.29
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ASM_SIZE_DIRECTIVE(limit)
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.align ALIGNARG(4)
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ASM_TYPE_DIRECTIVE(ln2_2,@object)
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ln2_2: .tfloat 0.3465735902799726547086160
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ASM_SIZE_DIRECTIVE(ln2_2)
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#ifdef PIC
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#define MO(op) op##@GOTOFF(%edx)
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#else
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#define MO(op) op
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#endif
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.text
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ENTRY(__ieee754_atanhl)
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movl 12(%esp), %ecx
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#ifdef PIC
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call 1f
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1: popl %edx
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addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %edx
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#endif
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andl $0x8000, %ecx // ECX == 0 iff X >= 0
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fldt MO(ln2_2) // 0.5*ln2
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xorl %ecx, 12(%esp)
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fldt 4(%esp) // |x| : 0.5*ln2
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fcoml MO(half) // |x| : 0.5*ln2
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fld %st(0) // |x| : |x| : 0.5*ln2
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fnstsw // |x| : |x| : 0.5*ln2
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sahf
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jae 2f
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fadd %st, %st(1) // |x| : 2*|x| : 0.5*ln2
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fld %st // |x| : |x| : 2*|x| : 0.5*ln2
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fsubrl MO(one) // 1-|x| : |x| : 2*|x| : 0.5*ln2
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fxch // |x| : 1-|x| : 2*|x| : 0.5*ln2
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fmul %st(2) // 2*|x|^2 : 1-|x| : 2*|x| : 0.5*ln2
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fdivp // (2*|x|^2)/(1-|x|) : 2*|x| : 0.5*ln2
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faddp // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
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fcoml MO(limit) // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
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fnstsw // 2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
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sahf
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jae 4f
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fyl2xp1 // 0.5*ln2*ld(1+2*|x|+(2*|x|^2)/(1-|x|))
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jecxz 3f
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fchs // 0.5*ln2*ld(1+2*x+(2*x^2)/(1-x))
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3: ret
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.align ALIGNARG(4)
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4: faddl MO(one) // 1+2*|x|+(2*|x|^2)/(1-|x|) : 0.5*ln2
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fyl2x // 0.5*ln2*ld(1+2*|x|+(2*|x|^2)/(1-|x|))
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jecxz 3f
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fchs // 0.5*ln2*ld(1+2*x+(2*x^2)/(1-x))
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3: ret
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.align ALIGNARG(4)
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2: faddl MO(one) // 1+|x| : |x| : 0.5*ln2
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fxch // |x| : 1+|x| : 0.5*ln2
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fsubrl MO(one) // 1-|x| : 1+|x| : 0.5*ln2
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fdivrp // (1+|x|)/(1-|x|) : 0.5*ln2
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fyl2x // 0.5*ln2*ld((1+|x|)/(1-|x|))
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jecxz 3f
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fchs // 0.5*ln2*ld((1+x)/(1-x))
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3: ret
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END(__ieee754_atanhl)
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