1/* $NetBSD: n_tan.S,v 1.4 2000/07/14 04:51:00 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. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by the University of 17 * California, Berkeley and its contributors. 18 * 4. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 * @(#)tan.s 8.1 (Berkeley) 6/4/93 35 */ 36 37#include <machine/asm.h> 38 39/* This is the implementation of Peter Tang's double precision 40 * tangent for the VAX using Bob Corbett's argument reduction. 41 * 42 * Notes: 43 * under 1,024,000 random arguments testing on [0,2*pi] 44 * tan() observed maximum error = 2.15 ulps 45 * 46 * double tan(arg) 47 * double arg; 48 * method: true range reduction to [-pi/4,pi/4], P. Tang & B. Corbett 49 * S. McDonald, April 4, 1985 50 */ 51ENTRY(tan, 0x0fc0) # save r6-r11 52 movq 4(ap),r0 53 bicw3 $0x807f,r0,r2 54 beql 1f # if x is zero or reserved operand then return x 55/* 56 * Save the PSL's IV & FU bits on the stack. 57 */ 58 movpsl r2 59 bicw3 $0xff9f,r2,-(sp) 60/* 61 * Clear the IV & FU bits. 62 */ 63 bicpsw $0x0060 64 jsb _C_LABEL(__libm_argred)+2 65/* 66 * At this point, 67 * r0 contains the quadrant number, 0, 1, 2, or 3; 68 * r2/r1 contains the reduced argument as a D-format number; 69 * r3 contains a F-format extension to the reduced argument; 70 * 71 * Save r3/r0 so that we can call cosine after calling sine. 72 */ 73 movq r2,-(sp) 74 movq r0,-(sp) 75/* 76 * Call sine. r4 = 0 implies sine. 77 */ 78 movl $0,r4 79 jsb _C_LABEL(__libm_sincos)+2 80/* 81 * Save sin(x) in r11/r10 . 82 */ 83 movd r0,r10 84/* 85 * Call cosine. r4 = 1 implies cosine. 86 */ 87 movq (sp)+,r0 88 movq (sp)+,r2 89 movl $1,r4 90 jsb _C_LABEL(__libm_sincos)+2 91 divd3 r0,r10,r0 92 bispsw (sp)+ 931: ret 94