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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 _EXP2D2_H_ #define _EXP2D2_H_ 1 #include /* * FUNCTION * vector double _exp2d2(vector double x) * * DESCRIPTION * _exp2d2 computes 2 raised to the input x for each * of the double word elements of x. Computation is * performed by observing the 2^(a+b) = 2^a * 2^b. * We decompose x into a and b (above) by letting. * a = ceil(x), b = x - a; * * 2^a is easily computed by placing a into the exponent * or a floating point number whose mantissa is all zeros. * * 2^b is computed using the polynomial approximation. * * __13_ * \ * \ * 2^x = / Ci*x^i * /____ * i=0 * * for x in the range 0.0 to 1.0. * */ #define EXP_C00 1.0 #define EXP_C01 6.93147180559945286227e-01 #define EXP_C02 2.40226506959100694072e-01 #define EXP_C03 5.55041086648215761801e-02 #define EXP_C04 9.61812910762847687873e-03 #define EXP_C05 1.33335581464284411157e-03 #define EXP_C06 1.54035303933816060656e-04 #define EXP_C07 1.52527338040598376946e-05 #define EXP_C08 1.32154867901443052734e-06 #define EXP_C09 1.01780860092396959520e-07 #define EXP_C10 7.05491162080112087744e-09 #define EXP_C11 4.44553827187081007394e-10 #define EXP_C12 2.56784359934881958182e-11 #define EXP_C13 1.36914888539041240648e-12 static __inline vector double _exp2d2(vector double vx) { vec_int4 ix, exp; vec_uint4 overflow, underflow; vec_float4 vxf; vec_double2 p1, p2, x2, x4, x8; vec_double2 vy, vxw, out_of_range; /* Compute: vxw = x - ceil(x) */ vxw = spu_add(vx, spu_splats(0.5)); vxf = spu_roundtf(vxw); ix = spu_convts(vxf, 0); ix = spu_add(ix, (vec_int4)spu_andc(spu_cmpgt(spu_splats(0.0f), vxf), spu_cmpeq(ix, spu_splats((int)0x80000000)))); vxf = spu_convtf(ix, 0); vxw = spu_sub(vx, spu_extend(vxf)); /* Detect overflow and underflow. If overflow, force the result * to infinity (at the end). */ exp = spu_shuffle(ix, ix, ((vec_uchar16) { 0,1,2,3, 0,1,2,3, 8,9,10,11, 8,9,10,11 })); overflow = spu_cmpgt(exp, 1023); underflow = spu_cmpgt(exp, -1023); out_of_range = (vec_double2)spu_and(overflow, ((vec_uint4) { 0x7FF00000, 0, 0x7FF00000, 0 })); /* Calculate the result by evaluating the 13th order polynomial. * For efficiency, the polynomial is broken into two parts and * evaluate then using nested * * result = (((((c13*x + c12)*x + c11)*x + c10)*x + c9)*x + c8)*x^8 + * ((((((c7*x + c6)*x + c5)*x + c4)*x + c3)*x + c2)*x + c1)*x + c0 */ p2 = spu_madd(spu_splats(EXP_C07), vxw, spu_splats(EXP_C06)); p1 = spu_madd(spu_splats(EXP_C13), vxw, spu_splats(EXP_C12)); x2 = spu_mul(vxw, vxw); p2 = spu_madd(vxw, p2, spu_splats(EXP_C05)); p1 = spu_madd(vxw, p1, spu_splats(EXP_C11)); x4 = spu_mul(x2, x2); p2 = spu_madd(vxw, p2, spu_splats(EXP_C04)); p1 = spu_madd(vxw, p1, spu_splats(EXP_C10)); p2 = spu_madd(vxw, p2, spu_splats(EXP_C03)); p1 = spu_madd(vxw, p1, spu_splats(EXP_C09)); x8 = spu_mul(x4, x4); p2 = spu_madd(vxw, p2, spu_splats(EXP_C02)); p1 = spu_madd(vxw, p1, spu_splats(EXP_C08)); p2 = spu_madd(vxw, p2, spu_splats(EXP_C01)); p2 = spu_madd(vxw, p2, spu_splats(EXP_C00)); vy = spu_madd(x8, p1, p2); /* Align the integer integer portion of x with the exponent. */ ix = spu_sl(ix, ((vec_uint4) { 20, 32, 20, 32 })); vy = (vec_double2)spu_add((vec_int4)vy, ix); /* Select the result if not overflow or underflow. Otherwise select the * the out of range value. */ return (spu_sel(vy, out_of_range, (vec_ullong2)spu_orc(overflow, underflow))); } #endif /* _EXP2D2_H_ */ #endif /* __SPU__ */