1/* $NetBSD: n_tan.S,v 1.5 2002/02/24 01:06:21 matt 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 */ 47ENTRY(tan, 0x0fc0) # save %r6-%r11 48 movq 4(%ap),%r0 49 bicw3 $0x807f,%r0,%r2 50 beql 1f # if x is zero or reserved operand then return x 51/* 52 * Save the PSL's IV & FU bits on the stack. 53 */ 54 movpsl %r2 55 bicw3 $0xff9f,%r2,-(%sp) 56/* 57 * Clear the IV & FU bits. 58 */ 59 bicpsw $0x0060 60 jsb _C_LABEL(__libm_argred)+2 61/* 62 * At this point, 63 * %r0 contains the quadrant number, 0, 1, 2, or 3; 64 * %r2/%r1 contains the reduced argument as a D-format number; 65 * %r3 contains a F-format extension to the reduced argument; 66 * 67 * Save %r3/%r0 so that we can call cosine after calling sine. 68 */ 69 movq %r2,-(%sp) 70 movq %r0,-(%sp) 71/* 72 * Call sine. %r4 = 0 implies sine. 73 */ 74 movl $0,%r4 75 jsb _C_LABEL(__libm_sincos)+2 76/* 77 * Save sin(x) in %r11/%r10 . 78 */ 79 movd %r0,%r10 80/* 81 * Call cosine. %r4 = 1 implies cosine. 82 */ 83 movq (%sp)+,%r0 84 movq (%sp)+,%r2 85 movl $1,%r4 86 jsb _C_LABEL(__libm_sincos)+2 87 divd3 %r0,%r10,%r0 88 bispsw (%sp)+ 891: ret 90