2 * Copyright (c) 1993,94 Winning Strategies, Inc.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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.
30 * $FreeBSD: head/lib/msun/i387/e_exp.S 217108 2011-01-07 16:13:12Z kib $
35 * J.T. Conklin (jtc@wimsey.com), Winning Strategies, Inc.
38 #include <machine/asm.h>
40 /* e^x = 2^(x * log2(e)) */
43 * If x is +-Inf, then the subtraction would give Inf-Inf = NaN.
44 * Avoid this. Also avoid it if x is NaN for convenience.
54 * Extended precision is needed to reduce the maximum error from
55 * hundreds of ulps to less than 1 ulp. Switch to it if necessary.
56 * We may as well set the rounding mode to to-nearest and mask traps
62 cmpl $0x0300,%eax /* RC == 0 && PC == 3? */
63 je 1f /* jump if mode is good */
68 fmulp /* x * log2(e) */
70 frndint /* int(x * log2(e)) */
72 fsubrp /* fract(x * log2(e)) */
73 f2xm1 /* 2^(fract(x * log2(e))) - 1 */
75 faddp /* 2^(fract(x * log2(e))) */
85 * Return 0 if x is -Inf. Otherwise just return x; when x is Inf
86 * this gives Inf, and when x is a NaN this gives the same result
87 * as (x + x) (x quieted).
89 cmpl $0xfff00000,8(%esp)
101 .section .note.GNU-stack,"",%progbits