/* * Written by J.T. Conklin <jtc@netbsd.org>. * Adapted for use as log2 by Ulrich Drepper <drepper@cygnus.com>. * Public domain. * * Changed to use fyl2xp1 for values near 1, <drepper@cygnus.com>. */#include <machine/asm.h>#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	.textENTRY(__ieee754_log2l)#ifdef PIC	LOAD_PIC_REG (dx)#endif	fldl	MO(one)	fldt	4(%esp)		// x : 1	fxam	fnstsw	fld	%st		// x : x : 1	sahf	jc	3f		// in case x is NaN or 盜nf4:	fsub	%st(2), %st	// x-1 : x : 1	fld	%st		// x-1 : x-1 : x : 1	fabs			// |x-1| : x-1 : x : 1	fcompl	MO(limit)	// x-1 : x : 1	fnstsw			// x-1 : x : 1	andb	$0x45, %ah	jz	2f	fstp	%st(1)		// x-1 : 1	fyl2xp1			// log(x)	ret2:	fstp	%st(0)		// x : 1	fyl2x			// log(x)	ret3:	jp	4b		// in case x is 盜nf	fstp	%st(1)	fstp	%st(1)	retEND (__ieee754_log2l)