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| /* International Business Machines Corporation, */ |
| /* Sony Computer Entertainment, Incorporated, */ |
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| /* -------------------------------------------------------------- */ |
| /* PROLOG END TAG zYx */ |
| #ifdef __SPU__ |
| |
| #ifndef _ACOSF4_H_ |
| #define _ACOSF4_H_ 1 |
| |
| #include <spu_intrinsics.h> |
| |
| #include "divf4.h" |
| #include "sqrtf4.h" |
| |
| /* |
| * FUNCTION |
| * vector float _acosf4(vector float x) |
| * |
| * DESCRIPTION |
| * The _acosf4 function computes the arc cosine for a vector of values x; |
| * that is the values whose cosine is x. Results are undefined if x is |
| * outside the range [-1, 1]. |
| * |
| * RETURNS |
| * The _acosf4 function returns the arc cosine in radians and the value is |
| * mathematically defined to be in the range [0, pi]. |
| * |
| */ |
| static __inline vector float _acosf4(vector float x) |
| { |
| vec_float4 zero = spu_splats(0.0f); |
| vec_float4 half = spu_splats(0.5f); |
| vec_float4 one = spu_splats(1.0f); |
| vec_float4 two = spu_splats(2.0f); |
| vec_float4 pi = spu_splats(3.1415925026e+00f); |
| vec_float4 pio2_hi = spu_splats(1.5707962513e+00f); |
| vec_float4 pio2_lo = spu_splats(7.5497894159e-08f); |
| |
| vec_float4 snan = (vec_float4)spu_splats((unsigned int)0x7FC00000); |
| vec_uint4 denorm_threshold = spu_splats((unsigned int)0x23000000); |
| vec_uint4 sign_mask = spu_splats((unsigned int)0x80000000); |
| |
| |
| vec_float4 p0 = (vec_float4)spu_splats((unsigned int)0x3E2AAAAB); |
| vec_float4 p1 = (vec_float4)spu_splats((unsigned int)0xBEA6B090); |
| vec_float4 p2 = (vec_float4)spu_splats((unsigned int)0x3E4E0AA8); |
| vec_float4 p3 = (vec_float4)spu_splats((unsigned int)0xBD241146); |
| vec_float4 p4 = (vec_float4)spu_splats((unsigned int)0x3A4F7F04); |
| vec_float4 p5 = (vec_float4)spu_splats((unsigned int)0x3811EF08); |
| |
| vec_float4 q1 = (vec_float4)spu_splats((unsigned int)0xC019D139); |
| vec_float4 q2 = (vec_float4)spu_splats((unsigned int)0x4001572D); |
| vec_float4 q3 = (vec_float4)spu_splats((unsigned int)0xBF303361); |
| vec_float4 q4 = (vec_float4)spu_splats((unsigned int)0x3D9DC62E); |
| |
| |
| vec_uint4 x_abs = spu_andc((vec_uint4)x,sign_mask); |
| vec_uint4 x_pos = spu_cmpgt(sign_mask,(vec_uint4)x); |
| |
| |
| vec_uint4 almost_half = spu_splats((unsigned int)0x3EFFFFFF); |
| vec_uint4 sel0 = spu_nand(spu_splats((unsigned int)0xFFFFFFFF),spu_cmpgt(x_abs,almost_half)); |
| vec_uint4 sel1 = spu_andc(x_pos,sel0); // pos |
| |
| vec_float4 za = spu_sel(spu_sel(spu_add(one,x),spu_sub(one,x),sel1) ,x,sel0); |
| vec_float4 zb = spu_sel(half,x,sel0); |
| |
| vec_float4 z = spu_mul(za,zb); |
| |
| vec_float4 p; |
| p = spu_madd(z,p5,p4); |
| p = spu_madd(p,z,p3); |
| p = spu_madd(p,z,p2); |
| p = spu_madd(p,z,p1); |
| p = spu_madd(p,z,p0); |
| p = spu_mul(p,z); |
| |
| vec_float4 q; |
| q = spu_madd(z,q4,q3); |
| q = spu_madd(q,z,q2); |
| q = spu_madd(q,z,q1); |
| q = spu_madd(q,z,one); |
| |
| // Only used by secondaries |
| vec_float4 s = _sqrtf4(z); |
| |
| vec_float4 r = _divf4(p,q); |
| |
| vec_float4 w1 = spu_msub(r,s,pio2_lo); |
| |
| |
| vec_float4 df = (vec_float4)spu_and((vec_uint4)s,0xFFFFF000); |
| vec_float4 c = _divf4(spu_nmsub(df,df,z),spu_add(s,df)); |
| vec_float4 w2 = spu_madd(r,s,c); |
| |
| vec_float4 result0 = spu_sub(pio2_hi,spu_sub(x,spu_nmsub(x,r,pio2_lo))); |
| |
| |
| vec_float4 result1 = spu_mul(two,spu_add(df,w2)); |
| vec_float4 result2 = spu_nmsub(two,spu_add(s,w1),pi); |
| |
| |
| vec_float4 result; |
| |
| result = spu_sel(result2,result1,sel1); |
| result = spu_sel(result,result0,sel0); |
| |
| // If |x|==1 then: |
| // if x == 1, return 0 |
| // else return pi |
| |
| vec_uint4 abs_one = spu_cmpeq(x_abs,(vec_uint4)one); |
| vec_uint4 out_of_bounds = spu_cmpgt(x_abs,(vec_uint4)one); |
| vec_uint4 underflow = spu_cmpgt(denorm_threshold,x_abs); |
| |
| |
| |
| result = spu_sel(result,spu_sel(pi,zero,x_pos),abs_one); |
| |
| // If 1 < |x| then return sNaN |
| result = spu_sel(result,snan,out_of_bounds); |
| |
| // If |x| < 2**-57, then return pi/2 (OFF BY 1 ULP) |
| result = spu_sel(result,spu_add(pio2_hi,pio2_lo),underflow); |
| |
| return result; |
| } |
| |
| #endif /* _ACOSF4_H_ */ |
| #endif /* __SPU__ */ |
| |
| |
