| /* -------------------------------------------------------------- */ |
| /* (C)Copyright 2001,2008, */ |
| /* International Business Machines Corporation, */ |
| /* Sony Computer Entertainment, Incorporated, */ |
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| /* -------------------------------------------------------------- */ |
| /* PROLOG END TAG zYx */ |
| #ifdef __SPU__ |
| |
| #ifndef _ASINF4_H_ |
| #define _ASINF4_H_ 1 |
| |
| #include <spu_intrinsics.h> |
| |
| #include "divf4.h" |
| #include "sqrtf4.h" |
| |
| /* |
| * FUNCTION |
| * vector float _asinf4(vector float x) |
| * |
| * DESCRIPTION |
| * The _asinf4 function computes the arc sine for a vector of values x; |
| * that is the values whose sine is x. Results are undefined if x is |
| * outside the range [-1, 1]. |
| * |
| */ |
| static __inline vector float _asinf4(vector float x) |
| { |
| /* The arcsin is computed using two different algorithms, depending |
| * upon the absolute value of the input. For inputs in the range |
| * [0, PI/4], it is computed as the ratio of two polynomials. |
| * |
| * asin(x) = p/q; |
| * |
| * where p = P11*x^11 + P09*x^9 + P07*x^7 + P05*x^5 + P03*x3 + x |
| * q = Q08*x^8 + Q06*x^6 + Q04*x^4 + Q02*x^2 + Q00 |
| * |
| * For the range of value [PI/4, 1], the arcsin is computed using: |
| * |
| * asin = PI/2 - sqrt(1 - x) * r; |
| * |
| * where r = C07*x^7 + C06*x^6 + C05*x^5 + C04*x^4 + C03*x^3 + C02*x^2 |
| * C01*x + C00; |
| */ |
| vector float r, r1, r2, r_hi, r_lo; |
| vector float xabs, x2, x4, x6; |
| vector float p, p_hi, p_lo; |
| vector float q, q_hi, q_lo; |
| vector float pi_over_2 = spu_splats(1.5707963267949f); |
| vector float pi_over_4 = spu_splats(0.7853981633974f); |
| vector unsigned int msb = spu_splats(0x80000000); |
| |
| |
| x2 = spu_mul(x, x); |
| x4 = spu_mul(x2, x2); |
| x6 = spu_mul(x4, x2); |
| |
| xabs = spu_andc(x, (vector float)msb); |
| |
| /* Compute arc-sin for values in the range [0, PI/4] |
| */ |
| p_hi = spu_madd(spu_splats(0.0000347933107596021167570f), x2, |
| spu_splats(0.000791534994289814532176f)); |
| p_hi = spu_madd(p_hi, x2, spu_splats(-0.0400555345006794114027f)); |
| |
| p_lo = spu_madd(spu_splats(0.201212532134862925881f), x2, |
| spu_splats(-0.325565818622400915405f)); |
| p_lo = spu_madd(p_lo, x2, spu_splats(0.166666666666666657415f)); |
| |
| p = spu_madd(p_hi, x6, p_lo); |
| |
| q_hi = spu_madd(spu_splats(0.0770381505559019352791f), x2, |
| spu_splats(-0.688283971605453293030f)); |
| q_hi = spu_madd(q_hi, x2, spu_splats(2.02094576023350569471f)); |
| |
| q_lo = spu_madd(spu_splats(-2.40339491173441421878f), x2, |
| spu_splats(1.0f)); |
| |
| q = spu_madd(q_hi, x4, q_lo); |
| |
| r1 = spu_madd(_divf4(p, q), spu_mul(xabs, x2), xabs); |
| |
| /* Compute arc-sin for values in the range [PI/4, 1] |
| */ |
| r_hi = spu_madd(spu_splats(-0.0012624911f), xabs, |
| spu_splats(0.0066700901f)); |
| r_hi = spu_madd(r_hi, xabs, spu_splats(-0.0170881256f)); |
| r_hi = spu_madd(r_hi, xabs, spu_splats(0.0308918810f)); |
| |
| r_lo = spu_madd(spu_splats(-0.0501743046f), xabs, |
| spu_splats(0.0889789874f)); |
| r_lo = spu_madd(r_lo, xabs, spu_splats(-0.2145988016f)); |
| r_lo = spu_madd(r_lo, xabs, pi_over_2); |
| |
| r = spu_madd(r_hi, x4, r_lo); |
| |
| r2 = spu_nmsub(r, _sqrtf4(spu_sub(spu_splats(1.0f), xabs)), |
| pi_over_2); |
| |
| /* Select the result depending upon the input value. Correct the |
| * sign of the result. |
| */ |
| return (spu_sel(spu_sel(r1, r2, spu_cmpgt(xabs, pi_over_4)), |
| x, msb)); |
| } |
| |
| #endif /* _ASINF4_H_ */ |
| #endif /* __SPU__ */ |
| |
| |