Real FFT F64 Functions

Functions
RISCV_DSP_ATTRIBUTE void	riscv_rfft_fast_f64 (riscv_rfft_fast_instance_f64 *S, float64_t *p, float64_t *pOut, uint8_t ifftFlag)
	Processing function for the Double Precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_32_f64 (riscv_rfft_fast_instance_f64 *S)
	Initialization function for the 32pt double precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_64_f64 (riscv_rfft_fast_instance_f64 *S)
	Initialization function for the 64pt Double Precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_128_f64 (riscv_rfft_fast_instance_f64 *S)
	Initialization function for the 128pt Double Precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_256_f64 (riscv_rfft_fast_instance_f64 *S)
	Initialization function for the 256pt Double Precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_512_f64 (riscv_rfft_fast_instance_f64 *S)
	Initialization function for the 512pt Double Precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_1024_f64 (riscv_rfft_fast_instance_f64 *S)
	Initialization function for the 1024pt Double Precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_2048_f64 (riscv_rfft_fast_instance_f64 *S)
	Initialization function for the 2048pt Double Precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_4096_f64 (riscv_rfft_fast_instance_f64 *S)
	Initialization function for the 4096pt Double Precision floating-point real FFT. More...
RISCV_DSP_ATTRIBUTE riscv_status	riscv_rfft_fast_init_f64 (riscv_rfft_fast_instance_f64 *S, uint16_t fftLen)
	Generic initialization function for the Double Precision floating-point real FFT. More...

Detailed Description

Function Documentation

riscv_rfft_fast_f64()

RISCV_DSP_ATTRIBUTE void riscv_rfft_fast_f64	(	riscv_rfft_fast_instance_f64 *	S,
		float64_t *	p,
		float64_t *	pOut,
		uint8_t	ifftFlag
	)

Processing function for the Double Precision floating-point real FFT.

Parameters

[in]	S	points to an riscv_rfft_fast_instance_f64 structure
[in]	p	points to input buffer (Source buffer is modified by this function.)
[in]	pOut	points to output buffer
[in]	ifftFlag	value = 0: RFFT value = 1: RIFFT

riscv_rfft_fast_init_1024_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_1024_f64

(

riscv_rfft_fast_instance_f64 *

S

)

Initialization function for the 1024pt Double Precision floating-point real FFT.

Parameters

[in,out]

S

points to an riscv_rfft_fast_instance_f64 structure

Returns

execution status

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

riscv_rfft_fast_init_128_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_128_f64

(

riscv_rfft_fast_instance_f64 *

S

)

Initialization function for the 128pt Double Precision floating-point real FFT.

Parameters

[in,out]

S

points to an riscv_rfft_fast_instance_f64 structure

Returns

execution status

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

riscv_rfft_fast_init_2048_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_2048_f64

(

riscv_rfft_fast_instance_f64 *

S

)

Initialization function for the 2048pt Double Precision floating-point real FFT.

Parameters

[in,out]

S

points to an riscv_rfft_fast_instance_f64 structure

Returns

execution status

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

riscv_rfft_fast_init_256_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_256_f64

(

riscv_rfft_fast_instance_f64 *

S

)

Initialization function for the 256pt Double Precision floating-point real FFT.

Parameters

[in,out]

S

points to an riscv_rfft_fast_instance_f64 structure

Returns

execution status

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

riscv_rfft_fast_init_32_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_32_f64

(

riscv_rfft_fast_instance_f64 *

S

)

Initialization function for the 32pt double precision floating-point real FFT.

Parameters

[in,out]

S

points to an riscv_rfft_fast_instance_f64 structure

Returns

execution status

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

riscv_rfft_fast_init_4096_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_4096_f64

(

riscv_rfft_fast_instance_f64 *

S

)

Initialization function for the 4096pt Double Precision floating-point real FFT.

Parameters

[in,out]

S

points to an riscv_rfft_fast_instance_f64 structure

Returns

execution status

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

riscv_rfft_fast_init_512_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_512_f64

(

riscv_rfft_fast_instance_f64 *

S

)

Initialization function for the 512pt Double Precision floating-point real FFT.

Parameters

[in,out]

S

points to an riscv_rfft_fast_instance_f64 structure

Returns

execution status

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

riscv_rfft_fast_init_64_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_64_f64

(

riscv_rfft_fast_instance_f64 *

S

)

Initialization function for the 64pt Double Precision floating-point real FFT.

Parameters

[in,out]

S

points to an riscv_rfft_fast_instance_f64 structure

Returns

execution status

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

riscv_rfft_fast_init_f64()

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_fast_init_f64	(	riscv_rfft_fast_instance_f64 *	S,
		uint16_t	fftLen
	)

Generic initialization function for the Double Precision floating-point real FFT.

Parameters

[in,out]	S	points to an riscv_rfft_fast_instance_f64 structure
[in]	fftLen	length of the Real Sequence

Returns

execution status

• RISCV_MATH_SUCCESS : Operation successful
• RISCV_MATH_ARGUMENT_ERROR : fftLen is not a supported length

Description

The parameter fftLen specifies the length of RFFT/CIFFT process. Supported FFT Lengths are 32, 64, 128, 256, 512, 1024, 2048, 4096.

This Function also initializes Twiddle factor table pointer and Bit reversal table pointer.

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 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.