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/* -------------------------------------------------------------- */
/* (C)Copyright 2001,2008, */
/* International Business Machines Corporation, */
/* Sony Computer Entertainment, Incorporated, */
/* Toshiba Corporation, */
/* */
/* All Rights Reserved. */
/* */
/* Redistribution and use in source and binary forms, with or */
/* without modification, are permitted provided that the */
/* following conditions are met: */
/* */
/* - Redistributions of source code must retain the above copyright*/
/* notice, this list of conditions and the following disclaimer. */
/* */
/* - Redistributions in binary form must reproduce the above */
/* copyright notice, this list of conditions and the following */
/* disclaimer in the documentation and/or other materials */
/* provided with the distribution. */
/* */
/* - Neither the name of IBM Corporation nor the names of its */
/* contributors may be used to endorse or promote products */
/* derived from this software without specific prior written */
/* permission. */
/* */
/* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND */
/* CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, */
/* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF */
/* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE */
/* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR */
/* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, */
/* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT */
/* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; */
/* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) */
/* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN */
/* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR */
/* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, */
/* EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
/* -------------------------------------------------------------- */
/* 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__ */
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