xref: /freebsd/lib/msun/i387/e_exp.S (revision 3a8617a83f16ffc9db4f96e1f0f21af94078e6b1)
1/*
2 * Copyright (c) 1993,94 Winning Strategies, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *      This product includes software developed by Winning Strategies, Inc.
16 * 4. The name of the author may not be used to endorse or promote products
17 *    derived from this software without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 */
30
31/*
32 * Written by:
33 *	J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
34 */
35
36#include <machine/asm.h>
37
38RCSID("$Id: e_exp.S,v 1.2 1994/03/12 01:30:27 jtc Exp $")
39
40/* e^x = 2^(x * log2(e)) */
41ENTRY(__ieee754_exp)
42	fldl	4(%esp)
43	fldl2e
44	fmulp				/* x * log2(e) */
45	fstl	%st(1)
46	frndint				/* int(x * log2(e)) */
47	fstl	%st(2)
48	fsubrp				/* fract(x * log2(e)) */
49	f2xm1				/* 2^(fract(x * log2(e))) - 1 */
50	fld1
51	faddp				/* 2^(fract(x * log2(e))) */
52	fscale				/* e^x */
53	ret
54