blob: 95efc8f7a2fbae8d9f9fe01e68e99bfeea731d52 (
plain) (
blame)
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
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
|
/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*
* Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>.
*/
#include <machine/asm.h>
RCSID("$NetBSD: e_log10.S,v 1.4 1995/05/08 23:49:24 jtc Exp $")
#ifdef __ELF__
.section .rodata
#else
.text
#endif
.align ALIGNARG(4)
ASM_TYPE_DIRECTIVE(one,@object)
one: .double 1.0
ASM_SIZE_DIRECTIVE(one)
/* It is not important that this constant is precise. It is only
a value which is known to be on the safe side for using the
fyl2xp1 instruction. */
ASM_TYPE_DIRECTIVE(limit,@object)
limit: .double 0.29
ASM_SIZE_DIRECTIVE(limit)
#ifdef PIC
#define MO(op) op##@GOTOFF(%edx)
#else
#define MO(op) op
#endif
.text
ENTRY(__ieee754_log10)
fldlg2 // log10(2)
fldl 4(%esp) // x : log10(2)
#ifdef PIC
call 1f
1: popl %edx
addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %edx
#endif
fld %st // x : x : log10(2)
fsubl MO(one) // x-1 : x : log10(2)
fld %st // x-1 : x-1 : x : log10(2)
fabs // |x-1| : x-1 : x : log10(2)
fcompl MO(limit) // x-1 : x : log10(2)
fnstsw // x-1 : x : log10(2)
sahf
ja 2f
fstp %st(1) // x-1 : log10(2)
fyl2xp1 // log10(x)
ret
2: fincstp // x : log10(2)
fyl2x // log10(x)
ret
END (__ieee754_log10)
|
