Texas Instruments TMS320C64X manual Math, DSPdotpsqr, Vector Dot Product and Square

DSP_dotp_sqr

4.5 Math

DSP_dotp_sqr	Vector Dot Product and Square
Function
		int DSP_dotp_sqr(int G, const short * restrict x, const short * restrict y, int *
		restrict r, int nx)
Arguments		G	Calculated value of G (used in the VSELP coder).
		x[nx]	First vector array
		y[nx]	Second vector array
		r	Result of vector dot product of x and y.
		nx	Number of elements. Must be multiple of 4, and ≥12.
		return int	New value of G.
Description		This routine performs an nx element dot product of x[ ] and y[ ] and stores it
		in r. It also squares each element of y[ ] and accumulates it in G. G is passed
		back to the calling function in register A4. This computation of G is used in the
		VSELP coder.
Algorithm		This is the C equivalent of the assembly code without restrictions. Note that
		the assembly code is hand optimized and restrictions may apply.

int DSP_dotp_sqr (int G,short *x,short *y,int *r, int nx)

{

short *y2; short *endPtr2; y2 = x;

for (endPtr2 = y2 + nx; y2 < endPtr2; y2++){ *r += *y * *y2;

G += *y * *y; y++;

}

return(G);

}

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