blob: 2884efa6ce116e2b8abbd007276f97bced79e702 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
|
/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*
* Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>.
*/
#include <machine/asm.h>
RCSID("$NetBSD: $")
/* e^x = 2^(x * log2l(e)) */
ENTRY(__ieee754_expl)
fldt 4(%esp)
/* I added the following ugly construct because expl(+-Inf) resulted
in NaN. The ugliness results from the bright minds at Intel.
For the i686 the code can be written better.
-- drepper@cygnus.com. */
fxam /* Is NaN or +-Inf? */
fstsw %ax
sahf
jnc .LnoInfNaN /* No, jump. */
jp .LisInf /* Is +-Inf, jump. */
.LnoInfNaN:
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 */
ret
.LisInf:
andb $2, %ah /* Test sign. */
jz .LpInf /* If positive, jump. */
fldz /* Set result to 0. */
.LpInf: ret
PSEUDO_END (__ieee754_expl)
|
