nrf_axon_xty_16_16_32_output_stride()

nrf_axon_result_e nrf_axon_xty_16_16_32_output_stride	(	const int16_t *	x_ptr,
		const int16_t *	y_ptr,
		int32_t *	out_ptr,
		uint16_t	length,
		uint8_t	rounding_bits,
		uint8_t	output_extra_stride,
		nrf_axon_syncmode_blocking_e	block_mode,
		bool	keep_reservation )

#include <include/drivers/axon/nrf_axon_dsp_intrinsics.h>

"xty output_stride" => "vector x times vector y with output_stride gaps between outputs" vector multiplies 2 16bit vectors to produce a 32bit vector, with option to have unpacked output vector.

Useful for applying a hamming window on real input before performing an FFT, which requires complex input. Pass output_extra_stride=1 and the output will be placed every other word in the real coefficients slots. A separate function would need to be called to 0 out the imaginary coefficients.

If output_extra_stride is not needed it can be set to 0, but using axon_xty_16_16_32() is preferred for better performance. It performs multiplication of 2 16bit vectors and produces a 32bit output.

Parameters

x_ptr	x vector input. 16bit integers packed.
y_ptr	y vector input. 16bit integers packed.
out_ptr	location to place output. Can safely overlap either input
length	number of of elements in the input vectors. Maximum value is 512.
rounding_bits	number of bits to round the output by.
output_extra_stride	number of gap words between each output.
block_mode	recommnended to be set to NRF_AXON_SYNC_MODE_BLOCKING_POLLING.
keep_reservation	set to true if there are subsequent axon operations to execute immediately on completion. true prevents axon from be taken by another user and/or being powered off. Set to false if axon will not be used immediately after to free axon for other users and/or power down if idle.

Returns

kAxonResultSuccess on success or a negative error code (see nrf_axon_result_e)