3   fp_trig.c: floating-point math routines for the Linux-m68k
6   Copyright (c) 1998-1999 David Huggins-Daines / Roman Zippel.
25 extern struct fp_ext *fp_fadd(struct fp_ext *dest, const struct fp_ext *src);
26 extern struct fp_ext *fp_fdiv(struct fp_ext *dest, const struct fp_ext *src);
29 fp_fsqrt(struct fp_ext *dest, struct fp_ext *src)  in fp_fsqrt()  argument
36 	fp_monadic_check(dest, src);  in fp_fsqrt()
41 	if (dest->sign) {  in fp_fsqrt()
49 	 *		 sqrt(m) * 2^(p)	, if e = 2*p  in fp_fsqrt()
50 	 * sqrt(m*2^e) =  in fp_fsqrt()
51 	 *		 sqrt(2*m) * 2^(p)	, if e = 2*p + 1  in fp_fsqrt()
54 	 * use the m or 2*m.  in fp_fsqrt()
57 	 * the integer part is assumed to be one, we place a 1 or 2 into  in fp_fsqrt()
60 	exp = dest->exp;  in fp_fsqrt()
61 	dest->exp = 0x3FFF;  in fp_fsqrt()
63 		dest->exp++;  in fp_fsqrt()
68 	 *	sqrt(x) = sqrt(a) + 1/(2*sqrt(a))*(x-a) + R  in fp_fsqrt()
70 	 *	sqrt(x) = 1 + 1/2*(x-1)  in fp_fsqrt()
71 	 *		= 1/2*(1+x)  in fp_fsqrt()
74 	dest->exp--;		/* * 1/2 */  in fp_fsqrt()
78 	 *	f(x) := x^2 - r  in fp_fsqrt()
82 	 *	x' := x - f(x)/f'(x)  in fp_fsqrt()
83 	 *	    = x - (x^2 -r)/(2*x)  in fp_fsqrt()
84 	 *	    = x - (x - r/x)/2  in fp_fsqrt()
85 	 *          = (2*x - x + r/x)/2  in fp_fsqrt()
86 	 *	    = (x + r/x)/2  in fp_fsqrt()
93 		dest->exp--;  in fp_fsqrt()
96 	dest->exp += (exp - 0x3FFF) / 2;  in fp_fsqrt()
102 fp_fetoxm1(struct fp_ext *dest, struct fp_ext *src)  in fp_fetoxm1()  argument
106 	fp_monadic_check(dest, src);  in fp_fetoxm1()
112 fp_fetox(struct fp_ext *dest, struct fp_ext *src)  in fp_fetox()  argument
116 	fp_monadic_check(dest, src);  in fp_fetox()
122 fp_ftwotox(struct fp_ext *dest, struct fp_ext *src)  in fp_ftwotox()  argument
126 	fp_monadic_check(dest, src);  in fp_ftwotox()
132 fp_ftentox(struct fp_ext *dest, struct fp_ext *src)  in fp_ftentox()  argument
136 	fp_monadic_check(dest, src);  in fp_ftentox()
142 fp_flogn(struct fp_ext *dest, struct fp_ext *src)  in fp_flogn()  argument
146 	fp_monadic_check(dest, src);  in fp_flogn()
152 fp_flognp1(struct fp_ext *dest, struct fp_ext *src)  in fp_flognp1()  argument
156 	fp_monadic_check(dest, src);  in fp_flognp1()
162 fp_flog10(struct fp_ext *dest, struct fp_ext *src)  in fp_flog10()  argument
166 	fp_monadic_check(dest, src);  in fp_flog10()
172 fp_flog2(struct fp_ext *dest, struct fp_ext *src)  in fp_flog2()  argument
176 	fp_monadic_check(dest, src);  in fp_flog2()
182 fp_fgetexp(struct fp_ext *dest, struct fp_ext *src)  in fp_fgetexp()  argument
186 	fp_monadic_check(dest, src);  in fp_fgetexp()
195 	fp_conv_long2ext(dest, (int)dest->exp - 0x3FFF);  in fp_fgetexp()
203 fp_fgetman(struct fp_ext *dest, struct fp_ext *src)  in fp_fgetman()  argument
207 	fp_monadic_check(dest, src);  in fp_fgetman()
215 	dest->exp = 0x3FFF;  in fp_fgetman()