Texas Instruments TMS320C64X manual DSPwvec, Weighted Vector Sum

DSP_w_vec

DSP_w_vec	Weighted Vector Sum
Function
		void DSP_w_vec(const short * restrict x, const short * restrict y, short m, short
		* restrict r, short nr)
Arguments		x[nr]	Vector being weighted. Must be double-word aligned.
		y[nr]	Summation vector. Must be double-word aligned.
		m	Weighting factor
		r[nr]	Output vector
		nr	Dimensions of the vectors. Must be multiple of 8 and ≥8.
Description		This routine is used to obtain the weighted vector sum. Both the inputs and
		output are 16-bit numbers.
Algorithm		This is the C equivalent of the assembly code without restrictions. Note that
		the assembly code is hand optimized and restrictions may apply.
		void DSP_w_vec(short x[ ],short y[ ],short m,
		short r[ ],short nr)
	{

short i;

for (i=0; i<nr; i++) {

r[i] = ((m * x[i]) >> 15) + y[i];

}

}

Special Requirements

-nr must be a multiple of 8 and ≥ 8.

-Vectors x[ ] and y[ ] must be double-word aligned.

Implementation Notes

- Bank Conflicts: No bank conflicts occur.

- Interruptibility: The code is interrupt-tolerant but not interruptible. - Input is loaded in double-words.

- Use of packed data processing to sustain throughput.

Benchmarks	Cycles	3 * nr/8 + 18
	Codesize	144 bytes

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