/*

 * Written by J.T. Conklin <jtc@netbsd.org>.

 * Public domain.

 *

 * Adapted for `long double' by Ulrich Drepper <drepper@cygnus.com>.

 * Adapted for x86-64 by Andreas Jaeger <aj@suse.de>.

 */

#include <machine/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:	.tfloat 0.29

	/* Please note:	 we use a double value here.  Since 1.0 has

	   an exact representation this does not effect the accuracy

	   but it helps to optimize the code.  */

one:	.double 1.0

/*

 * Use the fyl2xp1 function when the argument is in the range -0.29 to 0.29,

 * otherwise fyl2x with the needed extra computation.

 */

#ifdef PIC

#define MO(op) op##(%rip)

#else

#define MO(op) op

#endif

	.text

ENTRY(__log1pl)

	fldln2

	fldt	8(%rsp)

	fxam

	fnstsw

	fld	%st

	testb	$1, %ah

	jnz	3f		// in case x is NaN or ±Inf

4:

	fabs

	fldt	MO(limit)

	fcompp

	fnstsw

	andb	$1,%ah

	jz	2f

	movzwl	8+8(%rsp), %eax

	xorb	$0x80, %ah

	cmpl	$0xc040, %eax

	jae	5f

	faddl	MO(one)

5:	fyl2x

	ret

2:	fyl2xp1

	ret

3:	testb	$4, %ah

	jnz	4b		// in case x is ±Inf

	fstp	%st(1)

	fstp	%st(1)

	fadd	%st(0)

	ret

END (__log1pl)