Deprecated Real FFT Functions

RISCV_DSP_ATTRIBUTE void riscv_rfft_f32 (const riscv_rfft_instance_f32 *S, float32_t *pSrc, float32_t *pDst)
RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_init_f32 (riscv_rfft_instance_f32 *S, riscv_cfft_radix4_instance_f32 *S_CFFT, uint32_t fftLenReal, uint32_t ifftFlagR, uint32_t bitReverseFlag)
group Deprecated Real FFT Functions

Functions

RISCV_DSP_ATTRIBUTE void riscv_rfft_f32 (const riscv_rfft_instance_f32 *S, float32_t *pSrc, float32_t *pDst)

Processing function for the floating-point RFFT/RIFFT. Source buffer is modified by this function.

Deprecated:

Do not use this function. It has been superceded by riscv_rfft_fast_f32 and will be removed in the future.

Parameters:

  • S – [in] points to an instance of the floating-point RFFT/RIFFT structure

  • pSrc – [in] points to the input buffer

  • pDst – [out] points to the output buffer

RISCV_DSP_ATTRIBUTE riscv_status riscv_rfft_init_f32 (riscv_rfft_instance_f32 *S, riscv_cfft_radix4_instance_f32 *S_CFFT, uint32_t fftLenReal, uint32_t ifftFlagR, uint32_t bitReverseFlag)

Initialization function for the floating-point RFFT/RIFFT.

Deprecated:

Do not use this function. It has been superceded by riscv_rfft_fast_init_f32 and will be removed in the future.

Description

The parameter fftLenRealspecifies length of RFFT/RIFFT Process. Supported FFT Lengths are 128, 512, 2048.

The parameter ifftFlagR controls whether a forward or inverse transform is computed. Set(=1) ifftFlagR to calculate RIFFT, otherwise RFFT is calculated.

The parameter bitReverseFlag controls whether output is in normal order or bit reversed order. Set(=1) bitReverseFlag for output to be in normal order otherwise output is in bit reversed order.

This function also initializes Twiddle factor table.

Parameters:

  • S – [inout] points to an instance of the floating-point RFFT/RIFFT structure

  • S_CFFT – [inout] points to an instance of the floating-point CFFT/CIFFT structure

  • fftLenReal – [in] length of the FFT.

  • ifftFlagR – [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:

execution status

  • RISCV_MATH_SUCCESS : Operation successful

  • RISCV_MATH_ARGUMENT_ERROR : fftLenReal is not a supported length