1998-10-31 05:06:01 +03:00
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/* $NetBSD: n_tan.S,v 1.2 1998/10/31 02:06:02 matt Exp $ */
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1995-10-11 02:40:21 +03:00
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/*
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* Copyright (c) 1985, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* @(#)tan.s 8.1 (Berkeley) 6/4/93
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*/
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/* This is the implementation of Peter Tang's double precision
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* tangent for the VAX using Bob Corbett's argument reduction.
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*
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* Notes:
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* under 1,024,000 random arguments testing on [0,2*pi]
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* tan() observed maximum error = 2.15 ulps
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*
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* double tan(arg)
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* double arg;
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* method: true range reduction to [-pi/4,pi/4], P. Tang & B. Corbett
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* S. McDonald, April 4, 1985
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*/
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.text
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.align 1
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1998-10-31 05:06:01 +03:00
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.globl _tan
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.type _tan,@function
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1995-10-11 02:40:21 +03:00
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_tan: .word 0xffc # save r2-r11
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movq 4(ap),r0
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bicw3 $0x807f,r0,r2
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beql 1f # if x is zero or reserved operand then return x
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/*
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* Save the PSL's IV & FU bits on the stack.
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*/
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movpsl r2
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bicw3 $0xff9f,r2,-(sp)
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/*
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* Clear the IV & FU bits.
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*/
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bicpsw $0x0060
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jsb libm$argred
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/*
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* At this point,
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* r0 contains the quadrant number, 0, 1, 2, or 3;
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* r2/r1 contains the reduced argument as a D-format number;
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* r3 contains a F-format extension to the reduced argument;
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*
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* Save r3/r0 so that we can call cosine after calling sine.
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*/
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movq r2,-(sp)
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movq r0,-(sp)
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/*
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* Call sine. r4 = 0 implies sine.
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*/
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movl $0,r4
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jsb libm$sincos
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/*
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* Save sin(x) in r11/r10 .
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*/
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movd r0,r10
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/*
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* Call cosine. r4 = 1 implies cosine.
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*/
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movq (sp)+,r0
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movq (sp)+,r2
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movl $1,r4
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jsb libm$sincos
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divd3 r0,r10,r0
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bispsw (sp)+
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1: ret
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