97 lines
3.0 KiB
ArmAsm
97 lines
3.0 KiB
ArmAsm
/*
|
|
* Copyright (c) 1993,94 Winning Strategies, Inc.
|
|
* All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in the
|
|
* documentation and/or other materials provided with the distribution.
|
|
* 3. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by Winning Strategies, Inc.
|
|
* 4. The name of the author may not be used to endorse or promote products
|
|
* derived from this software without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
|
|
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
|
|
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
|
|
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
|
|
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
|
|
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
|
|
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
|
|
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
*/
|
|
|
|
/*
|
|
* Written by:
|
|
* J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
|
|
*/
|
|
|
|
#include <machine/asm.h>
|
|
|
|
RCSID("$Id: e_exp.S,v 1.6 1997/02/22 15:08:46 peter Exp $")
|
|
|
|
/* e^x = 2^(x * log2(e)) */
|
|
ENTRY(__ieee754_exp)
|
|
/*
|
|
* If x is +-Inf, then the subtraction would give Inf-Inf = NaN.
|
|
* Avoid this. Also avoid it if x is NaN for convenience.
|
|
*/
|
|
movl 8(%esp),%eax
|
|
andl $0x7fffffff,%eax
|
|
cmpl $0x7ff00000,%eax
|
|
jae x_Inf_or_NaN
|
|
|
|
fldl 4(%esp)
|
|
|
|
/*
|
|
* Ensure that the rounding mode is to nearest (to give the smallest
|
|
* possible fraction) and that the precision is as high as possible.
|
|
* We may as well mask interrupts if we switch the mode.
|
|
*/
|
|
fstcw 4(%esp)
|
|
movl 4(%esp),%eax
|
|
andl $0x0300,%eax
|
|
cmpl $0x0300,%eax /* RC == 0 && PC == 3? */
|
|
je 1f /* jump if mode is good */
|
|
movl $0x137f,8(%esp)
|
|
fldcw 8(%esp)
|
|
1:
|
|
fldl2e
|
|
fmulp /* x * log2(e) */
|
|
fstl %st(1)
|
|
frndint /* int(x * log2(e)) */
|
|
fstl %st(2)
|
|
fsubrp /* fract(x * log2(e)) */
|
|
f2xm1 /* 2^(fract(x * log2(e))) - 1 */
|
|
fld1
|
|
faddp /* 2^(fract(x * log2(e))) */
|
|
fscale /* e^x */
|
|
fstpl %st(1)
|
|
je 1f
|
|
fldcw 4(%esp)
|
|
1:
|
|
ret
|
|
|
|
x_Inf_or_NaN:
|
|
/*
|
|
* Return 0 if x is -Inf. Otherwise just return x, although the
|
|
* C version would return (x + x) (Real Indefinite) if x is a NaN.
|
|
*/
|
|
cmpl $0xfff00000,8(%esp)
|
|
jne x_not_minus_Inf
|
|
cmpl $0,4(%esp)
|
|
jne x_not_minus_Inf
|
|
fldz
|
|
ret
|
|
|
|
x_not_minus_Inf:
|
|
fldl 4(%esp)
|
|
ret
|