Complex FFT Q15

Macros
#define	FFTINIT(EXT, SIZE)
#define	CFFTINIT_Q15(LEN, LENTWIDDLE)

Functions
	CFFTINIT_Q15 (4096, 4096)
	Initialization function for the cfft q15 function for 4096 samples. More...
	CFFTINIT_Q15 (2048, 1024)
	Initialization function for the cfft q15 function for 2048 samples. More...
	CFFTINIT_Q15 (1024, 1024)
	Initialization function for the cfft q15 function for 1024 samples. More...
	CFFTINIT_Q15 (512, 256)
	Initialization function for the cfft q15 function for 512 samples. More...
	CFFTINIT_Q15 (256, 256)
	Initialization function for the cfft q15 function for 256 samples. More...
	CFFTINIT_Q15 (128, 64)
	Initialization function for the cfft q15 function for 128 samples. More...
	CFFTINIT_Q15 (64, 64)
	Initialization function for the cfft q15 function for 64 samples. More...
	CFFTINIT_Q15 (32, 16)
	Initialization function for the cfft q15 function for 32 samples. More...
	CFFTINIT_Q15 (16, 16)
	Initialization function for the cfft q15 function for 16 samples. More...
riscv_status	riscv_cfft_init_q15 (riscv_cfft_instance_q15 *S, uint16_t fftLen)
	Generic initialization function for the cfft q15 function. More...
void	riscv_cfft_q15 (const riscv_cfft_instance_q15 *S, q15_t *p1, uint8_t ifftFlag, uint8_t bitReverseFlag)
	Processing function for Q15 complex FFT. More...

Detailed Description

Macro Definition Documentation

CFFTINIT_Q15

#define CFFTINIT_Q15	(		LEN,
			LENTWIDDLE
	)

FFTINIT

#define FFTINIT	(		EXT,
			SIZE
	)

Function Documentation

CFFTINIT_Q15() [1/9]

CFFTINIT_Q15	(	1024	,
		1024
	)

Initialization function for the cfft q15 function for 1024 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

CFFTINIT_Q15() [2/9]

CFFTINIT_Q15	(	128	,
		64
	)

Initialization function for the cfft q15 function for 128 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

CFFTINIT_Q15() [3/9]

CFFTINIT_Q15	(	16	,
		16
	)

Initialization function for the cfft q15 function for 16 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

CFFTINIT_Q15() [4/9]

CFFTINIT_Q15	(	2048	,
		1024
	)

Initialization function for the cfft q15 function for 2048 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

CFFTINIT_Q15() [5/9]

CFFTINIT_Q15	(	256	,
		256
	)

Initialization function for the cfft q15 function for 256 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

CFFTINIT_Q15() [6/9]

CFFTINIT_Q15	(	32	,
		16
	)

Initialization function for the cfft q15 function for 32 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

CFFTINIT_Q15() [7/9]

CFFTINIT_Q15	(	4096	,
		4096
	)

Initialization function for the cfft q15 function for 4096 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

CFFTINIT_Q15() [8/9]

CFFTINIT_Q15	(	512	,
		256
	)

Initialization function for the cfft q15 function for 512 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

CFFTINIT_Q15() [9/9]

CFFTINIT_Q15	(	64	,
		64
	)

Initialization function for the cfft q15 function for 64 samples.

Parameters

[in,out]

S

points to an instance of the floating-point CFFT structure

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

riscv_cfft_init_q15()

riscv_status riscv_cfft_init_q15	(	riscv_cfft_instance_q15 *	S,
		uint16_t	fftLen
	)

Generic initialization function for the cfft q15 function.

Parameters

[in,out]	S	points to an instance of the floating-point CFFT structure
[in]	fftLen	fft length (number of complex samples)

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : an error is detected

Use of this function is mandatory only for the MVE version of the FFT.

Other versions can still initialize directly the data structure using variables declared in riscv_const_structs.h

This function should be used only if you don't know the FFT sizes that you'll need at build time. The use of this function will prevent the linker from removing the FFT tables that are not needed and the library code size will be bigger than needed.

If you use NMSIS-DSP as a static library, and if you know the FFT sizes that you need at build time, then it is better to use the initialization functions defined for each FFT size.

riscv_cfft_q15()

void riscv_cfft_q15	(	const riscv_cfft_instance_q15 *	S,
		q15_t *	p1,
		uint8_t	ifftFlag,
		uint8_t	bitReverseFlag
	)

Processing function for Q15 complex FFT.

Parameters

[in]	S	points to an instance of Q15 CFFT structure
[in,out]	p1	points to the complex data buffer of size 2*fftLen. Processing occurs in-place
[in]	ifftFlag	flag that selects transform direction value = 0: forward transform value = 1: inverse transform
[in]	bitReverseFlag	flag that enables / disables bit reversal of output value = 0: disables bit reversal of output value = 1: enables bit reversal of output

Returns

none