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