1/*	$NetBSD: n_tan.S,v 1.8 2024/05/06 15:33:04 riastradh Exp $	*/
2/*
3 * Copyright (c) 1985, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. Neither the name of the University nor the names of its contributors
15 *    may be used to endorse or promote products derived from this software
16 *    without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
28 * SUCH DAMAGE.
29 *
30 *	@(#)tan.s	8.1 (Berkeley) 6/4/93
31 */
32
33#include <machine/asm.h>
34
35/*  This is the implementation of Peter Tang's double precision
36 *  tangent for the VAX using Bob Corbett's argument reduction.
37 *
38 *  Notes:
39 *       under 1,024,000 random arguments testing on [0,2*pi]
40 *       tan() observed maximum error = 2.15 ulps
41 *
42 * double tan(arg)
43 * double arg;
44 * method: true range reduction to [-pi/4,pi/4], P. Tang  &  B. Corbett
45 * S. McDonald, April 4,  1985
46 */
47
48WEAK_ALIAS(tanl, _tanl)
49STRONG_ALIAS(_tanl, _tan)
50
51WEAK_ALIAS(tan, _tan)
52ENTRY(_tan, 0x0fc0)		# save %r6-%r11
53	movq	4(%ap),%r0
54	bicw3	$0x807f,%r0,%r2
55	beql	1f		# if x is zero or reserved operand then return x
56/*
57 * Save the PSL's IV & FU bits on the stack.
58 */
59	movpsl	%r2
60	bicw3	$0xff9f,%r2,-(%sp)
61/*
62 *  Clear the IV & FU bits.
63 */
64	bicpsw	$0x0060
65	jsb	_C_LABEL(__libm_argred)+2
66/*
67 *  At this point,
68 *	   %r0  contains the quadrant number, 0, 1, 2, or 3;
69 *	%r2/%r1  contains the reduced argument as a D-format number;
70 *  	   %r3  contains a F-format extension to the reduced argument;
71 *
72 *  Save  %r3/%r0  so that we can call cosine after calling sine.
73 */
74	movq	%r2,-(%sp)
75	movq	%r0,-(%sp)
76/*
77 *  Call sine.  %r4 = 0  implies sine.
78 */
79	movl	$0,%r4
80	jsb	_C_LABEL(__libm_sincos)+2
81/*
82 *  Save  sin(x)  in  %r11/%r10 .
83 */
84	movd	%r0,%r10
85/*
86 *  Call cosine.  %r4 = 1  implies cosine.
87 */
88	movq	(%sp)+,%r0
89	movq	(%sp)+,%r2
90	movl	$1,%r4
91	jsb	_C_LABEL(__libm_sincos)+2
92	divd3	%r0,%r10,%r0
93	bispsw	(%sp)+
941:	ret
95END(_tan)
96
97WEAK_ALIAS(tanf, _tanf)
98ENTRY(_tanf, 0)
99	cvtfd	4(%ap),-(%sp)
100	calls	$2,_C_LABEL(_tan)
101	cvtdf	%r0,%r0
102	ret
103END(_tanf)
104