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/*
* Written by J.T. Conklin <jtc@netbsd.org>.
* Public domain.
*/
#include <machine/asm.h>
#include <i386-math-asm.h>
RCSID("$NetBSD: s_log1p.S,v 1.7 1995/05/09 00:10:58 jtc Exp $")
.section .rodata
.align ALIGNARG(4)
/* The fyl2xp1 can only be used for values in
-1 + sqrt(2) / 2 <= x <= 1 - sqrt(2) / 2
0.29 is a safe value.
*/
limit: .double 0.29
one: .double 1.0
DEFINE_DBL_MIN
#ifdef PIC
# define MO(op) op##@GOTOFF(%edx)
#else
# define MO(op) op
#endif
/*
* Use the fyl2xp1 function when the argument is in the range -0.29 to 0.29,
* otherwise fyl2x with the needed extra computation.
*/
.text
ENTRY(__log1p)
fldln2
fldl 4(%esp)
#ifdef PIC
LOAD_PIC_REG (dx)
#endif
fxam
fnstsw
fld %st
sahf
jc 3f // in case x is NaN or ±Inf
4: fabs
fcompl MO(limit)
fnstsw
sahf
jc 2f
faddl MO(one)
fyl2x
ret
2: fyl2xp1
DBL_CHECK_FORCE_UFLOW_NONNAN
ret
3: jp 4b // in case x is ±Inf
fstp %st(1)
fstp %st(1)
ret
END (__log1p)
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