mirror of
git://sourceware.org/git/glibc.git
synced 2024-12-09 04:11:27 +08:00
90 lines
2.8 KiB
ArmAsm
90 lines
2.8 KiB
ArmAsm
/* ix87 specific implementation of exp(x)-1.
|
|
Copyright (C) 1996-1997, 2005, 2012 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
Contributed by Ulrich Drepper <drepper@cygnus.com>, 1996.
|
|
Based on code by John C. Bowman <bowman@ipp-garching.mpg.de>.
|
|
Corrections by H.J. Lu (hjl@gnu.ai.mit.edu), 1997.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, write to the Free
|
|
Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
|
|
02111-1307 USA. */
|
|
|
|
/* Using: e^x - 1 = 2^(x * log2(e)) - 1 */
|
|
|
|
#include <sysdep.h>
|
|
#include <machine/asm.h>
|
|
|
|
.section .rodata
|
|
|
|
.align ALIGNARG(4)
|
|
ASM_TYPE_DIRECTIVE(minus1,@object)
|
|
minus1: .double -1.0
|
|
ASM_SIZE_DIRECTIVE(minus1)
|
|
ASM_TYPE_DIRECTIVE(one,@object)
|
|
one: .double 1.0
|
|
ASM_SIZE_DIRECTIVE(one)
|
|
ASM_TYPE_DIRECTIVE(l2e,@object)
|
|
l2e: .tfloat 1.442695040888963407359924681002
|
|
ASM_SIZE_DIRECTIVE(l2e)
|
|
|
|
#ifdef PIC
|
|
#define MO(op) op##@GOTOFF(%edx)
|
|
#else
|
|
#define MO(op) op
|
|
#endif
|
|
|
|
.text
|
|
ENTRY(__expm1)
|
|
movzwl 4+6(%esp), %eax
|
|
xorb $0x80, %ah // invert sign bit (now 1 is "positive")
|
|
cmpl $0xc086, %eax // is num >= 704?
|
|
jae HIDDEN_JUMPTARGET (__exp)
|
|
|
|
fldl 4(%esp) // x
|
|
fxam // Is NaN or +-Inf?
|
|
fstsw %ax
|
|
movb $0x45, %ch
|
|
andb %ah, %ch
|
|
cmpb $0x40, %ch
|
|
je 3f // If +-0, jump.
|
|
#ifdef PIC
|
|
LOAD_PIC_REG (dx)
|
|
#endif
|
|
cmpb $0x05, %ch
|
|
je 2f // If +-Inf, jump.
|
|
|
|
fldt MO(l2e) // log2(e) : x
|
|
fmulp // log2(e)*x
|
|
fld %st // log2(e)*x : log2(e)*x
|
|
frndint // int(log2(e)*x) : log2(e)*x
|
|
fsubr %st, %st(1) // int(log2(e)*x) : fract(log2(e)*x)
|
|
fxch // fract(log2(e)*x) : int(log2(e)*x)
|
|
f2xm1 // 2^fract(log2(e)*x)-1 : int(log2(e)*x)
|
|
fscale // 2^(log2(e)*x)-2^int(log2(e)*x) : int(log2(e)*x)
|
|
fxch // int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
|
|
fldl MO(one) // 1 : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
|
|
fscale // 2^int(log2(e)*x) : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
|
|
fsubrl MO(one) // 1-2^int(log2(e)*x) : int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
|
|
fstp %st(1) // 1-2^int(log2(e)*x) : 2^(log2(e)*x)-2^int(log2(e)*x)
|
|
fsubrp %st, %st(1) // 2^(log2(e)*x)
|
|
ret
|
|
|
|
2: testl $0x200, %eax // Test sign.
|
|
jz 3f // If positive, jump.
|
|
fstp %st
|
|
fldl MO(minus1) // Set result to -1.0.
|
|
3: ret
|
|
END(__expm1)
|
|
weak_alias (__expm1, expm1)
|