61 lines
1.2 KiB
C++
61 lines
1.2 KiB
C++
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/* Copyright 1987 Manx Software Systems, Inc */
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#include <math.h>
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#include <errno.h>
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static double sincos(double x, register double y, int sgn);
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double cos(double x)
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{
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return sincos(x, fabs(x) + 1.57079632679489661923, 0);
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}
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double sin(register double x)
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{
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if (x < 0.0)
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return sincos(x,-x,1);
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else
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return sincos(x,x,0);
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}
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#define R1 -0.16666666666666665052e+00
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#define R2 +0.83333333333331650314e-02
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#define R3 -0.19841269841201840457e-03
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#define R4 +0.27557319210152756119e-05
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#define R5 -0.25052106798274584544e-07
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#define R6 +0.16058936490371589114e-09
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#define R7 -0.76429178068910467734e-12
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#define R8 +0.27204790957888846175e-14
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#define YMAX 6.7465e09
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static
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double sincos(double x, register double y, int sgn)
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{
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double xn;
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register double f;
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# define g (y)
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if (y >= YMAX) {
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errno = ERANGE;
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return 0.0;
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}
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if (modf(y * 0.31830988618379067154, &xn) >= 0.5)
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++xn;
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if ((int)xn & 1)
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sgn = !sgn;
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if (fabs(x) != y)
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xn -= 0.5;
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g = modf(fabs(x), &x); /* break into fraction and integer parts */
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f = ((x - xn*(3217.0/1024)) + g) - xn*-8.9089102067615373566e-6;
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if (fabs(f) > 2.3283e-10) {
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g = f*f;
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f = (((((((R8*g R7)*g R6)*g R5)*g
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R4)*g R3)*g R2)*g R1)*g*f+f;
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}
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if (sgn)
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f = -f;
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return f;
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#undef g
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}
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