projects / thirdparty / glibc.git / blame
| Commit | Line | Data |
|---|---|---|
| d38cd08c UD |
1 | /* |
| 2 | * Written by J.T. Conklin <jtc@netbsd.org>. | |
| 3 | * Public domain. | |
| 4 | * Adapted for float by Ulrich Drepper <drepper@cygnus.com>. | |
| 5 | * | |
| 6 | * Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>. | |
| 7 | */ | |
| 8 | ||
| 9 | #include <machine/asm.h> | |
| 10 | ||
| 11 | RCSID("$NetBSD: e_log.S,v 1.4 1995/05/08 23:48:39 jtc Exp $") | |
| 12 | ||
| 13 | #ifdef __ELF__ | |
| 14 | .section .rodata | |
| 15 | #else | |
| 16 | .text | |
| 17 | #endif | |
| 18 | .align ALIGNARG(4) | |
| 19 | ASM_TYPE_DIRECTIVE(one,@object) | |
| 20 | one: .double 1.0 | |
| 21 | ASM_SIZE_DIRECTIVE(one) | |
| 22 | /* It is not important that this constant is precise. It is only | |
| 23 | a value which is known to be on the safe side for using the | |
| 24 | fyl2xp1 instruction. */ | |
| 25 | ASM_TYPE_DIRECTIVE(limit,@object) | |
| 26 | limit: .double 0.29 | |
| 27 | ASM_SIZE_DIRECTIVE(limit) | |
| 28 | ||
| 29 | ||
| 30 | #ifdef PIC | |
| 31 | #define MO(op) op##@GOTOFF(%edx) | |
| 32 | #else | |
| 33 | #define MO(op) op | |
| 34 | #endif | |
| 35 | ||
| 36 | .text | |
| 37 | ENTRY(__ieee754_logf) | |
| 38 | fldln2 // log(2) | |
| 39 | flds 4(%esp) // x : log(2) | |
| 32c075e1 JJ |
40 | fxam |
| 41 | fnstsw | |
| d38cd08c | 42 | #ifdef PIC |
| fee732e5 | 43 | LOAD_PIC_REG (dx) |
| d38cd08c UD |
44 | #endif |
| 45 | fld %st // x : x : log(2) | |
| 32c075e1 JJ |
46 | sahf |
| 47 | jc 3f // in case x is NaN or +-Inf | |
| 48 | 4: fsubl MO(one) // x-1 : x : log(2) | |
| d38cd08c UD |
49 | fld %st // x-1 : x-1 : x : log(2) |
| 50 | fabs // |x-1| : x-1 : x : log(2) | |
| 51 | fcompl MO(limit) // x-1 : x : log(2) | |
| 52 | fnstsw // x-1 : x : log(2) | |
| 0d8733c4 UD |
53 | andb $0x45, %ah |
| 54 | jz 2f | |
| d38cd08c UD |
55 | fstp %st(1) // x-1 : log(2) |
| 56 | fyl2xp1 // log(x) | |
| 57 | ret | |
| 58 | ||
| 6bc31da0 | 59 | 2: fstp %st(0) // x : log(2) |
| d38cd08c UD |
60 | fyl2x // log(x) |
| 61 | ret | |
| 32c075e1 JJ |
62 | |
| 63 | 3: jp 4b // in case x is +-Inf | |
| 64 | fstp %st(1) | |
| 65 | fstp %st(1) | |
| 66 | ret | |
| d38cd08c | 67 | END (__ieee754_logf) |