Complex FFT Q15

CFFTINIT_Q15 (4096, 4096)
CFFTINIT_Q15 (2048, 1024)
CFFTINIT_Q15 (1024, 1024)
CFFTINIT_Q15 (512, 256)
CFFTINIT_Q15 (256, 256)
CFFTINIT_Q15 (128, 64)
CFFTINIT_Q15 (64, 64)
CFFTINIT_Q15 (32, 16)
CFFTINIT_Q15 (16, 16)
riscv_status riscv_cfft_init_q15(riscv_cfft_instance_q15 *S, uint16_t fftLen)
void riscv_cfft_q15(const riscv_cfft_instance_q15 *S, q15_t *p1, uint8_t ifftFlag, uint8_t bitReverseFlag)
FFTINIT(EXT, SIZE)
CFFTINIT_Q15(LEN, LENTWIDDLE)
group ComplexFFTQ15

Defines

FFTINIT(EXT, SIZE)
CFFTINIT_Q15(LEN, LENTWIDDLE)

Functions

CFFTINIT_Q15 (4096, 4096)

Initialization function for the cfft q15 function for 4096 samples.

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

Parameters

S[inout] 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

CFFTINIT_Q15 (2048, 1024)

Initialization function for the cfft q15 function for 2048 samples.

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

Parameters

S[inout] 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

CFFTINIT_Q15 (1024, 1024)

Initialization function for the cfft q15 function for 1024 samples.

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

Parameters

S[inout] 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

CFFTINIT_Q15 (512, 256)

Initialization function for the cfft q15 function for 512 samples.

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

Parameters

S[inout] 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

CFFTINIT_Q15 (256, 256)

Initialization function for the cfft q15 function for 256 samples.

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

Parameters

S[inout] 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

CFFTINIT_Q15 (128, 64)

Initialization function for the cfft q15 function for 128 samples.

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

Parameters

S[inout] 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

CFFTINIT_Q15 (64, 64)

Initialization function for the cfft q15 function for 64 samples.

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

Parameters

S[inout] 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

CFFTINIT_Q15 (32, 16)

Initialization function for the cfft q15 function for 32 samples.

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

Parameters

S[inout] 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

CFFTINIT_Q15 (16, 16)

Initialization function for the cfft q15 function for 16 samples.

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

Parameters

S[inout] 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

riscv_status riscv_cfft_init_q15(riscv_cfft_instance_q15 *S, uint16_t fftLen)

Generic initialization function for the cfft q15 function.

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.

Parameters
  • S[inout] points to an instance of the floating-point CFFT structure

  • fftLen[in] fft length (number of complex samples)

Returns

execution status

  • RISCV_MATH_SUCCESS : Operation successful

  • RISCV_MATH_ARGUMENT_ERROR : an error is detected

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
  • S[in] points to an instance of Q15 CFFT structure

  • p1[inout] points to the complex data buffer of size 2*fftLen. Processing occurs in-place

  • ifftFlag[in] flag that selects transform direction

    • value = 0: forward transform

    • value = 1: inverse transform

  • bitReverseFlag[in] flag that enables / disables bit reversal of output

    • value = 0: disables bit reversal of output

    • value = 1: enables bit reversal of output

Returns

none