sincosd2.h

Newlib 嵌入式 C库 标准实现代码

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/* PROLOG END TAG zYx                                              */
#ifdef __SPU__
#ifndef _SINCOSD2_H_
#define _SINCOSD2_H_	1

#include <spu_intrinsics.h>

#include "cos_sin.h"

/*
 * FUNCTION
 *  void _sincosd2(vector double x, vector double *sx, vector double *cx)
 *
 * DESCRIPTION
 *	The _sincosd2 function computes the sine and cosine of a vector of 
 *	angles (expressed in radians) to an accuracy of a double precision
 *	floating point.
 *
 *
 */

static __inline void _sincosd2(vector double angle, 
                               vector double *sinx,
                               vector double *cosx)
{
    vec_int4    octant;
    vec_ullong2 select;
    vec_double2 cos, sin;
    vec_double2 toggle_sign;

    /* Range reduce the input angle x into the range -PI/4 to PI/4
     * by performing simple modulus.
     */
    MOD_PI_OVER_FOUR(angle, octant);

    /* Compute the cosine and sine of the range reduced input.
     */
    COMPUTE_COS_SIN(angle, cos, sin);

    /*
     * See the comments for the sind2 and cosd2 functions for an
     * explanation of the following steps.
     */
    octant = spu_shuffle(octant, octant, ((vec_uchar16) { 0,1,2,3, 0,1,2,3, 8,9,10,11, 8,9,10,11 }));
    select = (vec_ullong2)spu_cmpeq(spu_and(octant, 2), 0);

    toggle_sign = (vec_double2)spu_sl(spu_and(spu_add(octant, 2), 4), ((vec_uint4) { 29,32,29,32 }));
    *cosx = spu_xor(spu_sel(sin, cos, select), toggle_sign);

    toggle_sign = (vec_double2)spu_sl(spu_and(octant, 4), ((vec_uint4) { 29,32,29,32 }));
    *sinx = spu_xor(spu_sel(cos, sin, select), toggle_sign);

    return;
}

#endif /* _SINCOSD2_H_ */
#endif /* __SPU__ */