n_scalbn.S revision 1.2 
1/*-
2 * Copyright (c) 2011 The NetBSD Foundation, Inc.
3 * All rights reserved.
4 *
5 * This code is derived from software contributed to The NetBSD Foundation
6 * by Matt Thomas of 3am Software Foundry.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
18 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
19 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
20 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
21 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
22 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
23 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
24 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
25 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
26 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
27 * POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <machine/asm.h>
31#include <sys/errno.h>
32
33RCSID("$NetBSD: n_scalbn.S,v 1.2 2013/04/27 18:39:28 joerg Exp $")
34
35WEAK_ALIAS(ldexp,_scalbln)
36WEAK_ALIAS(ldexpf,_scalblnf)
37WEAK_ALIAS(ldexpl,_scalblnl)
38
39ENTRY(scalbnf, 0)
40	cvtfd	4(%ap), %r0
41	movl	8(%ap), %r2
42	jr	1f
43
44ALTENTRY(scalbnl)
45ENTRY(scalbn, 0)
46	movd	4(%ap), %r0
47	movl	12(%ap), %r2
48
49	/*
50	 * First see if the result will be within bounds
51	 */
521:	cmpl	%r2,$(256+55)
53	jgeq	overflow
54	cmpl	%r2,$-(256+55)
55	jleq	underflow
56
57	extzv	$7, $9, %r0, %r3	/* extract exponent */
58	jneq	5f			/* 0 * N is still 0 */
59	cmpw	%r3, $-256		/* is this a NAN? */
60	jgtr	2f			/*    nope */
61	ret
62
632:	movzbl	%r3, %r3		/* clear sign bit */
64	addl2	%r2, %r3		/* add to exponent */
65	jleq	underflow		/*   <= 0? */
66
673:	jbs	$8, %r3, overflow	/* did exponent overflow? */
68	insv	$7, $8, %r3, %r0	/* replace exponent */
69	ret
70
71underflow:
72	clrq	%r0			/* return 0.0 */
73	jr	copysign		/* or mabye -0.0 */
74overflow:
75	pushl	$ERANGE			/* overflow */
76	calls	$1, _C_LABEL(infnan)	/* possibly signal */
77copysign:
78	jbc	$15, 4(%ap), 5f		/* if clear, don't set sign-bit */
79	bisw2	$0x8000, %r0		/* preserve sign-bit */
805:
81	ret
82