 CMSIS-DSP  Version 1.9.0 CMSIS DSP Software Library

## Functions

void arm_scale_f16 (const float16_t *pSrc, float16_t scale, float16_t *pDst, uint32_t blockSize)
Multiplies a floating-point vector by a scalar. More...

void arm_scale_f32 (const float32_t *pSrc, float32_t scale, float32_t *pDst, uint32_t blockSize)
Multiplies a floating-point vector by a scalar. More...

void arm_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. More...

void arm_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. More...

void arm_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. More...

## Description

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

```    pDst[n] = pSrc[n] * scale,   0 <= n < blockSize.
```

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:

```    pDst[n] = (pSrc[n] * scaleFract) << shift,   0 <= n < blockSize.
```

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

```    scale = scaleFract * 2^shift.
```

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

## Function Documentation

 void arm_scale_f16 ( const float16_t * pSrc, float16_t scale, float16_t * pDst, uint32_t blockSize )
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
Returns
none
 void arm_scale_f32 ( const float32_t * pSrc, float32_t scale, float32_t * pDst, uint32_t blockSize )
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
Returns
none
 void arm_scale_q15 ( const q15_t * pSrc, q15_t scaleFract, int8_t shift, q15_t * pDst, uint32_t blockSize )
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
Returns
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.
 void arm_scale_q31 ( const q31_t * pSrc, q31_t scaleFract, int8_t shift, q31_t * pDst, uint32_t blockSize )
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
Returns
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.
 void arm_scale_q7 ( const q7_t * pSrc, q7_t scaleFract, int8_t shift, q7_t * pDst, uint32_t blockSize )
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
Returns
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.