kfrexpd.s

早期freebsd实现

/*-
 * Copyright (c) 1985 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Computer Consoles Inc.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)Kfrexpd.s	7.1 (Berkeley) 12/6/90
 */

#include "../tahoe/SYS.h"

	.text
ENTRY(Kfrexpd, 0)
	subl3	$60,fp,sp
	clrl	-60(fp)
	clrl	-56(fp)
	tstl	4(fp)
	jgeq	1f
	lnd	4(fp)
	std	4(fp)
	movl	$1,-56(fp)
1:
	cmpd2	4(fp),one
	jleq	1f
2:
	cmpd2	4(fp),one
	jleq	3f
	addl2	$1,-60(fp)
	pushl	16(fp)		# hfs
	pushl	two+4		# ldd	2.0
	pushl	two
	pushl	8(fp)
	pushl	4(fp)		# acc
	callf	$24,_Kdivd
	ldd	r0
	std	4(fp)
	jbr	2b
1:	cmpd2	4(fp),half
	jlss	2f
	jbr	3f
0:
	subl2	$1,-60(fp)
	pushl	16(fp)		# hfs
	ldd	two; pushd	# 2.0
	ldd	4(fp); pushd	# acc
	callf	$24,_Kmuld
	ldd	r0
	std	4(fp)
2:
	cmpd2	4(fp),half
	jlss	0b
3:	movl	-60(fp),*12(fp)
	tstl	-56(fp)
	jeql	1f
	lnd	4(fp)
	std	4(fp)
1:
	movl	8(fp),r1
	movl	4(fp),r0
	ret
	.data
	.align 2
one:	.long	0x40800000, 0x00000000 # .double 1
two:	.long	0x41000000, 0x00000000 # .double 2
half:	.long	0x40000000, 0x00000000 # .double 0.5