Texas Instruments TMS320C64X manual DSPfirgenhM17rA8X8

DSP_fir_gen_hM17_rA8X8

DSP_fir_gen_hM17_rA8X8		FIR Filter
Function	void DSP_fir_gen_hM17_rA8X8 (const short * restrict x, const short * restrict
	h, short * restrict r, int nh, int nr)
Arguments	x[nr+nh−1]		Pointer to input array of size nr + nh − 1.
	h[nh]		Pointer to coefficient array of size nh (coefficients must be in
			reverse order).
	r[nr]		Pointer to output array of size nr. Must be double word
			aligned.
	nh		Number of coefficients. Must be ≥17.
	nr		Number of samples to calculate. Must be a multiple of 8.
Description	Computes a real FIR filter (direct-form) using coefficients stored in vector h[ ].
	The real data input is stored in vector x[ ]. The filter output result is stored in
	vector r[ ]. It operates on 16-bit data with a 32-bit accumulate. The filter
	calculates nr output samples using nh coefficients.
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_fir_gen(short *x, short *h, short *r, int nh, int nr)

{

int i, j, sum;

for (j = 0; j < nr; j++) { sum = 0;

for (i = 0; i < nh; i++) sum += x[i + j] * h[i];

r[j] = sum >> 15;

}

}

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