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37 /* PROLOG END TAG zYx */
38 #ifdef __SPU__
39 #ifndef _COSHF4_H_
40 #define _COSHF4_H_ 1
41
42 #include <spu_intrinsics.h>
43
44 #include "expf4.h"
45 #include "recipf4.h"
46
47
48 /*
49 * FUNCTION
50 * vector float _coshf4(vector float x)
51 *
52 * DESCRIPTION
53 * The _coshf4 function computes the hyperbolic cosines of a vector of
54 * angles (expressed in radians) to an accuracy of a single precision
55 * floating point.
56 *
57 */
_coshf4(vector float x)58 static __inline vector float _coshf4(vector float x)
59 {
60 // 1.0000 (above this number, use sinh(x) = 0.5 * (e^x - e^-x)
61 vec_uint4 threshold = (vec_uint4)spu_splats(0x3F800000);
62
63 vec_uint4 sign_mask = (vec_uint4)spu_splats(0x80000000);
64
65 // Coefficents for the Taylor series
66 vec_float4 f02 = spu_splats(5.0000000000000000E-1f); // 1/2!
67 vec_float4 f04 = spu_splats(4.1666666666666667E-2f); // 1/4!
68 vec_float4 f06 = spu_splats(1.3888888888888889E-3f); // 1/6!
69 vec_float4 f08 = spu_splats(2.4801587301587302E-5f); // 1/8!
70 vec_float4 f10 = spu_splats(2.7557319223985891E-7f); // 1/10!
71 vec_float4 f12 = spu_splats(2.0876756987868099E-9f); // 1/12!
72
73 // Perform the calculation as a Taylor series
74 vec_float4 result;
75 vector float x2 = spu_mul(x,x);
76 result = spu_madd(x2,f12,f10);
77 result = spu_madd(x2,result,f08);
78 result = spu_madd(x2,result,f06);
79 result = spu_madd(x2,result,f04);
80 result = spu_madd(x2,result,f02);
81 result = spu_madd(x2,result,spu_splats(1.0f));
82
83
84 // Perform calculation as a function of 0.5 * (e^x - e^-x)
85 vec_float4 ex = _expf4(x);
86 vec_float4 ex_inv = _recipf4(ex);
87
88 vec_float4 r2= spu_add(ex,ex_inv);
89 r2 = spu_mul(r2,f02); // we can reused f02 here
90
91 vec_uint4 xabs = spu_andc((vec_uint4)x,sign_mask);
92 vec_uint4 use_exp = spu_cmpgt(xabs,threshold);
93
94 // Select either the Taylor or exp version
95 result = spu_sel(result,r2,use_exp);
96
97 return result;
98 }
99 #endif /* _COSHF4_H_ */
100 #endif /* __SPU__ */
101
