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89 lines
2.7 KiB
ArmAsm
89 lines
2.7 KiB
ArmAsm
/* ix87 specific implementation of exp(x)-1.
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Copyright (C) 1996, 1997 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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Based on code by John C. Bowman <bowman@ipp-garching.mpg.de>.
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Corrections by H.J. Lu (hjl@gnu.ai.mit.edu), 1997.
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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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/* Using: e^x - 1 = 2^(x * log2(e)) - 1 */
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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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ASM_TYPE_DIRECTIVE(minus1,@object)
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minus1: .double -1.0
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ASM_SIZE_DIRECTIVE(minus1)
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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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ASM_TYPE_DIRECTIVE(l2e,@object)
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l2e: .tfloat 1.442695040888963407359924681002
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ASM_SIZE_DIRECTIVE(l2e)
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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(__expm1l)
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fldt 4(%esp) // x
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fxam // Is NaN or +-Inf?
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fstsw %ax
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movb $0x45, %ch
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andb %ah, %ch
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cmpb $0x40, %ch
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je 3f // If +-0, jump.
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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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cmpb $0x05, %ch
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je 2f // If +-Inf, jump.
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fldt MO(l2e) // log2(e) : x
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fmulp // log2(e)*x
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fld %st // log2(e)*x : log2(e)*x
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frndint // int(log2(e)*x) : log2(e)*x
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fsubr %st, %st(1) // int(log2(e)*x) : fract(log2(e)*x)
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fxch // fract(log2(e)*x) : int(log2(e)*x)
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f2xm1 // 2^fract(log2(e)*x)-1 : int(log2(e)*x)
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fscale // 2^(log2(e)*x)-2^int(log2(e)*x) : int(log2(e)*x)
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fxch // int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
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fldl MO(one) // 1 : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
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fscale // 2^int(log2(e)*x) : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
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fsubrl MO(one) // 1-2^int(log2(e)*x) : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
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fstp %st(1) // 1-2^int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
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fsubrp %st, %st(1) // 2^(log2(e)*x)
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ret
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2: testl $0x200, %eax // Test sign.
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jz 3f // If positive, jump.
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fstp %st
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fldl MO(minus1) // Set result to -1.0.
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3: ret
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END(__expm1l)
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weak_alias (__expm1l, expm1l)
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