diff options
Diffstat (limited to 'sysdeps/libm-i387/e_log.S')
| -rw-r--r-- | sysdeps/libm-i387/e_log.S | 52 |
1 files changed, 48 insertions, 4 deletions
diff --git a/sysdeps/libm-i387/e_log.S b/sysdeps/libm-i387/e_log.S index 2a51d7520c..43d430332c 100644 --- a/sysdeps/libm-i387/e_log.S +++ b/sysdeps/libm-i387/e_log.S @@ -1,15 +1,59 @@ /* * 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_log.S,v 1.4 1995/05/08 23:48:39 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_log) - fldln2 - fldl 4(%esp) - fyl2x + fldln2 // log(2) + fldl 4(%esp) // x : log(2) +#ifdef PIC + call 1f +1: popl %edx + addl $_GLOBAL_OFFSET_TABLE_+[.-1b], %edx +#endif + fld %st // x : x : log(2) + fsubl MO(one) // x-1 : x : log(2) + fld %st // x-1 : x-1 : x : log(2) + fabs // |x-1| : x-1 : x : log(2) + fcompl MO(limit) // x-1 : x : log(2) + fnstsw // x-1 : x : log(2) + sahf + ja 2f + fstp %st(1) // x-1 : log(2) + fyl2xp1 // log(x) + ret + +2: fincstp // x : log(2) + fyl2x // log(x) ret -PSEUDO_END (__ieee754_log) +END (__ieee754_log) |