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 1.8 2024/05/07 15:15:31 riastradh Exp $")
34
35WEAK_ALIAS(scalbn,_scalbn)
36WEAK_ALIAS(scalbnl,_scalbnl)
37WEAK_ALIAS(scalbnf,_scalbnf)
38WEAK_ALIAS(ldexp,_scalbn)
39WEAK_ALIAS(ldexpf,_scalbnf)
40WEAK_ALIAS(ldexpl,_scalbnl)
41
42ENTRY(_scalbnf, 0)
43	cvtfd	4(%ap), %r0
44	movl	8(%ap), %r2
45	jr	1f
46END(_scalbnf)
47
48STRONG_ALIAS(_scalbnl, _scalbn)
49ENTRY(_scalbn, 0)
50	movd	4(%ap), %r0
51	movl	12(%ap), %r2
52
53	/*
54	 * First see if the result will be within bounds
55	 */
561:	cmpl	%r2,$(256+55)
57	jgeq	overflow
58	cmpl	%r2,$-(256+55)
59	jleq	underflow
60
61	extzv	$7, $9, %r0, %r3	/* extract exponent */
62	jneq	5f			/* 0 * N is still 0 */
63	cmpw	%r3, $-256		/* is this a NAN? */
64	jgtr	2f			/*    nope */
65	ret
66
672:	movzbl	%r3, %r3		/* clear sign bit */
68	addl2	%r2, %r3		/* add to exponent */
69	jleq	underflow		/*   <= 0? */
70
713:	jbs	$8, %r3, overflow	/* did exponent overflow? */
72	insv	$7, $8, %r3, %r0	/* replace exponent */
73	ret
74
75underflow:
76	clrq	%r0			/* return 0.0 */
77	jr	copysign		/* or maybe -0.0 */
78overflow:
79	pushl	$ERANGE			/* overflow */
80	calls	$1, _C_LABEL(infnan)	/* possibly signal */
81copysign:
82	jbc	$15, 4(%ap), 5f		/* if clear, don't set sign-bit */
83	bisw2	$0x8000, %r0		/* preserve sign-bit */
845:
85	ret
86END(_scalbn)
87