Vector Scale

void riscv_scale_f32(const float32_t *pSrc, float32_t scale, float32_t *pDst, uint32_t blockSize)
void riscv_scale_q15(const q15_t *pSrc, q15_t scaleFract, int8_t shift, q15_t *pDst, uint32_t blockSize)
void riscv_scale_q31(const q31_t *pSrc, q31_t scaleFract, int8_t shift, q31_t *pDst, uint32_t blockSize)
void riscv_scale_q7(const q7_t *pSrc, q7_t scaleFract, int8_t shift, q7_t *pDst, uint32_t blockSize)
group BasicScale

Multiply a vector by a scalar value. For floating-point data, the algorithm used is:

In the fixed-point Q7, Q15, and Q31 functions, scale is represented by a fractional multiplication scaleFract and an arithmetic shift shift. The shift allows the gain of the scaling operation to exceed 1.0. The algorithm used with fixed-point data is:

The overall scale factor applied to the fixed-point data is

The functions support in-place computation allowing the source and destination pointers to reference the same memory buffer.

Functions

void riscv_scale_f32(const float32_t *pSrc, float32_t scale, float32_t *pDst, uint32_t blockSize)

Multiplies a floating-point vector by a scalar.

Return

none

Parameters
  • [in] pSrc: points to the input vector

  • [in] scale: scale factor to be applied

  • [out] pDst: points to the output vector

  • [in] blockSize: number of samples in each vector

void riscv_scale_q15(const q15_t *pSrc, q15_t scaleFract, int8_t shift, q15_t *pDst, uint32_t blockSize)

Multiplies a Q15 vector by a scalar.

Return

none

Scaling and Overflow Behavior

The input data *pSrc and scaleFract are in 1.15 format. These are multiplied to yield a 2.30 intermediate result and this is shifted with saturation to 1.15 format.

Parameters
  • [in] pSrc: points to the input vector

  • [in] scaleFract: fractional portion of the scale value

  • [in] shift: number of bits to shift the result by

  • [out] pDst: points to the output vector

  • [in] blockSize: number of samples in each vector

void riscv_scale_q31(const q31_t *pSrc, q31_t scaleFract, int8_t shift, q31_t *pDst, uint32_t blockSize)

Multiplies a Q31 vector by a scalar.

Return

none

Scaling and Overflow Behavior

The input data *pSrc and scaleFract are in 1.31 format. These are multiplied to yield a 2.62 intermediate result and this is shifted with saturation to 1.31 format.

Parameters
  • [in] pSrc: points to the input vector

  • [in] scaleFract: fractional portion of the scale value

  • [in] shift: number of bits to shift the result by

  • [out] pDst: points to the output vector

  • [in] blockSize: number of samples in each vector

void riscv_scale_q7(const q7_t *pSrc, q7_t scaleFract, int8_t shift, q7_t *pDst, uint32_t blockSize)

Multiplies a Q7 vector by a scalar.

Return

none

Scaling and Overflow Behavior

The input data *pSrc and scaleFract are in 1.7 format. These are multiplied to yield a 2.14 intermediate result and this is shifted with saturation to 1.7 format.

Parameters
  • [in] pSrc: points to the input vector

  • [in] scaleFract: fractional portion of the scale value

  • [in] shift: number of bits to shift the result by

  • [out] pDst: points to the output vector

  • [in] blockSize: number of samples in each vector