34 lines
767 B
C
34 lines
767 B
C
/*
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* This file is part of the UCB release of Plan 9. It is subject to the license
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* terms in the LICENSE file found in the top-level directory of this
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* distribution and at http://akaros.cs.berkeley.edu/files/Plan9License. No
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* part of the UCB release of Plan 9, including this file, may be copied,
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* modified, propagated, or distributed except according to the terms contained
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* in the LICENSE file.
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*/
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#include <u.h>
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#include <libc.h>
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/*
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atan2 discovers what quadrant the angle
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is in and calls atan.
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*/
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double
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jehanne_atan2(double arg1, double arg2)
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{
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if(arg1+arg2 == arg1) {
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if(arg1 >= 0)
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return PIO2;
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return -PIO2;
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}
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arg1 = jehanne_atan(arg1/arg2);
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if(arg2 < 0) {
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if(arg1 <= 0)
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return arg1 + PI;
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return arg1 - PI;
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}
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return arg1;
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}
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