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Removed error on fat32 library, seems now to be able navigate among sectors in...
Removed error on fat32 library, seems now to be able navigate among sectors in both directions. Improved SDLCD drawing performances by almost 1000x.
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arm_fir_interpolate_f32.c
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/ lib / src / stm32f4 / CPU / CMSIS / DSP_Lib / Source / FilteringFunctions / arm_fir_interpolate_f32.c
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Added ARM CMSIS for fast math and circle drawing function for ili9328 driver.
 r41 /* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date: 15. July 2011
* $Revision: V1.0.10
*
* Project: CMSIS DSP Library
* Title: arm_fir_interpolate_f32.c
*
* Description: FIR interpolation for floating-point sequences.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.0.10 2011/7/15
* Big Endian support added and Merged M0 and M3/M4 Source code.
*
* Version 1.0.3 2010/11/29
* Re-organized the CMSIS folders and updated documentation.
*
* Version 1.0.2 2010/11/11
* Documentation updated.
*
* Version 1.0.1 2010/10/05
* Production release and review comments incorporated.
*
* Version 1.0.0 2010/09/20
* Production release and review comments incorporated
*
* Version 0.0.7 2010/06/10
* Misra-C changes done
* -------------------------------------------------------------------- */
#include "arm_math.h"
/**
* @defgroup FIR_Interpolate Finite Impulse Response (FIR) Interpolator
*
* These functions combine an upsampler (zero stuffer) and an FIR filter.
* They are used in multirate systems for increasing the sample rate of a signal without introducing high frequency images.
* Conceptually, the functions are equivalent to the block diagram below:
* \image html FIRInterpolator.gif "Components included in the FIR Interpolator functions"
* After upsampling by a factor of <code>L</code>, the signal should be filtered by a lowpass filter with a normalized
* cutoff frequency of <code>1/L</code> in order to eliminate high frequency copies of the spectrum.
* The user of the function is responsible for providing the filter coefficients.
*
* The FIR interpolator functions provided in the CMSIS DSP Library combine the upsampler and FIR filter in an efficient manner.
* The upsampler inserts <code>L-1</code> zeros between each sample.
* Instead of multiplying by these zero values, the FIR filter is designed to skip them.
* This leads to an efficient implementation without any wasted effort.
* The functions operate on blocks of input and output data.
* <code>pSrc</code> points to an array of <code>blockSize</code> input values and
* <code>pDst</code> points to an array of <code>blockSize*L</code> output values.
*
* The library provides separate functions for Q15, Q31, and floating-point data types.
*
* \par Algorithm:
* The functions use a polyphase filter structure:
* <pre>
* y[n] = b[0] * x[n] + b[L] * x[n-1] + ... + b[L*(phaseLength-1)] * x[n-phaseLength+1]
* y[n+1] = b[1] * x[n] + b[L+1] * x[n-1] + ... + b[L*(phaseLength-1)+1] * x[n-phaseLength+1]
* ...
* y[n+(L-1)] = b[L-1] * x[n] + b[2*L-1] * x[n-1] + ....+ b[L*(phaseLength-1)+(L-1)] * x[n-phaseLength+1]
* </pre>
* This approach is more efficient than straightforward upsample-then-filter algorithms.
* With this method the computation is reduced by a factor of <code>1/L</code> when compared to using a standard FIR filter.
* \par
* <code>pCoeffs</code> points to a coefficient array of size <code>numTaps</code>.
* <code>numTaps</code> must be a multiple of the interpolation factor <code>L</code> and this is checked by the
* initialization functions.
* Internally, the function divides the FIR filter's impulse response into shorter filters of length
* <code>phaseLength=numTaps/L</code>.
* Coefficients are stored in time reversed order.
* \par
* <pre>
* {b[numTaps-1], b[numTaps-2], b[N-2], ..., b[1], b[0]}
* </pre>
* \par
* <code>pState</code> points to a state array of size <code>blockSize + phaseLength - 1</code>.
* Samples in the state buffer are stored in the order:
* \par
* <pre>
* {x[n-phaseLength+1], x[n-phaseLength], x[n-phaseLength-1], x[n-phaseLength-2]....x[0], x[1], ..., x[blockSize-1]}
* </pre>
* The state variables are updated after each block of data is processed, the coefficients are untouched.
*
* \par Instance Structure
* The coefficients and state variables for a filter are stored together in an instance data structure.
* A separate instance structure must be defined for each filter.
* Coefficient arrays may be shared among several instances while state variable array should be allocated separately.
* There are separate instance structure declarations for each of the 3 supported data types.
*
* \par Initialization Functions
* There is also an associated initialization function for each data type.
* The initialization function performs the following operations:
* - Sets the values of the internal structure fields.
* - Zeros out the values in the state buffer.
* - Checks to make sure that the length of the filter is a multiple of the interpolation factor.
*
* \par
* Use of the initialization function is optional.
* However, if the initialization function is used, then the instance structure cannot be placed into a const data section.
* To place an instance structure into a const data section, the instance structure must be manually initialized.
* The code below statically initializes each of the 3 different data type filter instance structures
* <pre>
* arm_fir_interpolate_instance_f32 S = {L, phaseLength, pCoeffs, pState};
* arm_fir_interpolate_instance_q31 S = {L, phaseLength, pCoeffs, pState};
* arm_fir_interpolate_instance_q15 S = {L, phaseLength, pCoeffs, pState};
* </pre>
* where <code>L</code> is the interpolation factor; <code>phaseLength=numTaps/L</code> is the
* length of each of the shorter FIR filters used internally,
* <code>pCoeffs</code> is the address of the coefficient buffer;
* <code>pState</code> is the address of the state buffer.
* Be sure to set the values in the state buffer to zeros when doing static initialization.
*
* \par Fixed-Point Behavior
* Care must be taken when using the fixed-point versions of the FIR interpolate filter functions.
* In particular, the overflow and saturation behavior of the accumulator used in each function must be considered.
* Refer to the function specific documentation below for usage guidelines.
*/
/**
* @addtogroup FIR_Interpolate
* @{
*/
/**
* @brief Processing function for the floating-point FIR interpolator.
* @param[in] *S points to an instance of the floating-point FIR interpolator structure.
* @param[in] *pSrc points to the block of input data.
* @param[out] *pDst points to the block of output data.
* @param[in] blockSize number of input samples to process per call.
* @return none.
*/
void arm_fir_interpolate_f32(
const arm_fir_interpolate_instance_f32 * S,
float32_t * pSrc,
float32_t * pDst,
uint32_t blockSize)
{
float32_t *pState = S->pState; /* State pointer */
float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
float32_t *pStateCurnt; /* Points to the current sample of the state */
float32_t *ptr1, *ptr2; /* Temporary pointers for state and coefficient buffers */
#ifndef ARM_MATH_CM0
/* Run the below code for Cortex-M4 and Cortex-M3 */
float32_t sum0; /* Accumulators */
float32_t x0, c0; /* Temporary variables to hold state and coefficient values */
uint32_t i, blkCnt, j; /* Loop counters */
uint16_t phaseLen = S->phaseLength, tapCnt; /* Length of each polyphase filter component */
/* S->pState buffer contains previous frame (phaseLen - 1) samples */
/* pStateCurnt points to the location where the new input data should be written */
pStateCurnt = S->pState + (phaseLen - 1u);
/* Total number of intput samples */
blkCnt = blockSize;
/* Loop over the blockSize. */
while(blkCnt > 0u)
{
/* Copy new input sample into the state buffer */
*pStateCurnt++ = *pSrc++;
/* Address modifier index of coefficient buffer */
j = 1u;
/* Loop over the Interpolation factor. */
i = S->L;
while(i > 0u)
{
/* Set accumulator to zero */
sum0 = 0.0f;
/* Initialize state pointer */
ptr1 = pState;
/* Initialize coefficient pointer */
ptr2 = pCoeffs + (S->L - j);
/* Loop over the polyPhase length. Unroll by a factor of 4.
** Repeat until we've computed numTaps-(4*S->L) coefficients. */
tapCnt = phaseLen >> 2u;
while(tapCnt > 0u)
{
/* Read the coefficient */
c0 = *(ptr2);
/* Upsampling is done by stuffing L-1 zeros between each sample.
* So instead of multiplying zeros with coefficients,
* Increment the coefficient pointer by interpolation factor times. */
ptr2 += S->L;
/* Read the input sample */
x0 = *(ptr1++);
/* Perform the multiply-accumulate */
sum0 += x0 * c0;
/* Read the coefficient */
c0 = *(ptr2);
/* Increment the coefficient pointer by interpolation factor times. */
ptr2 += S->L;
/* Read the input sample */
x0 = *(ptr1++);
/* Perform the multiply-accumulate */
sum0 += x0 * c0;
/* Read the coefficient */
c0 = *(ptr2);
/* Increment the coefficient pointer by interpolation factor times. */
ptr2 += S->L;
/* Read the input sample */
x0 = *(ptr1++);
/* Perform the multiply-accumulate */
sum0 += x0 * c0;
/* Read the coefficient */
c0 = *(ptr2);
/* Increment the coefficient pointer by interpolation factor times. */
ptr2 += S->L;
/* Read the input sample */
x0 = *(ptr1++);
/* Perform the multiply-accumulate */
sum0 += x0 * c0;
/* Decrement the loop counter */
tapCnt--;
}
/* If the polyPhase length is not a multiple of 4, compute the remaining filter taps */
tapCnt = phaseLen % 0x4u;
while(tapCnt > 0u)
{
/* Perform the multiply-accumulate */
sum0 += *(ptr1++) * (*ptr2);
/* Increment the coefficient pointer by interpolation factor times. */
ptr2 += S->L;
/* Decrement the loop counter */
tapCnt--;
}
/* The result is in the accumulator, store in the destination buffer. */
*pDst++ = sum0;
/* Increment the address modifier index of coefficient buffer */
j++;
/* Decrement the loop counter */
i--;
}
/* Advance the state pointer by 1
* to process the next group of interpolation factor number samples */
pState = pState + 1;
/* Decrement the loop counter */
blkCnt--;
}
/* Processing is complete.
** Now copy the last phaseLen - 1 samples to the satrt of the state buffer.
** This prepares the state buffer for the next function call. */
/* Points to the start of the state buffer */
pStateCurnt = S->pState;
tapCnt = (phaseLen - 1u) >> 2u;
/* copy data */
while(tapCnt > 0u)
{
*pStateCurnt++ = *pState++;
*pStateCurnt++ = *pState++;
*pStateCurnt++ = *pState++;
*pStateCurnt++ = *pState++;
/* Decrement the loop counter */
tapCnt--;
}
tapCnt = (phaseLen - 1u) % 0x04u;
while(tapCnt > 0u)
{
*pStateCurnt++ = *pState++;
/* Decrement the loop counter */
tapCnt--;
}
#else
/* Run the below code for Cortex-M0 */
float32_t sum; /* Accumulator */
uint32_t i, blkCnt; /* Loop counters */
uint16_t phaseLen = S->phaseLength, tapCnt; /* Length of each polyphase filter component */
/* S->pState buffer contains previous frame (phaseLen - 1) samples */
/* pStateCurnt points to the location where the new input data should be written */
pStateCurnt = S->pState + (phaseLen - 1u);
/* Total number of intput samples */
blkCnt = blockSize;
/* Loop over the blockSize. */
while(blkCnt > 0u)
{
/* Copy new input sample into the state buffer */
*pStateCurnt++ = *pSrc++;
/* Loop over the Interpolation factor. */
i = S->L;
while(i > 0u)
{
/* Set accumulator to zero */
sum = 0.0f;
/* Initialize state pointer */
ptr1 = pState;
/* Initialize coefficient pointer */
ptr2 = pCoeffs + (i - 1u);
/* Loop over the polyPhase length */
tapCnt = phaseLen;
while(tapCnt > 0u)
{
/* Perform the multiply-accumulate */
sum += *ptr1++ * *ptr2;
/* Increment the coefficient pointer by interpolation factor times. */
ptr2 += S->L;
/* Decrement the loop counter */
tapCnt--;
}
/* The result is in the accumulator, store in the destination buffer. */
*pDst++ = sum;
/* Decrement the loop counter */
i--;
}
/* Advance the state pointer by 1
* to process the next group of interpolation factor number samples */
pState = pState + 1;
/* Decrement the loop counter */
blkCnt--;
}
/* Processing is complete.
** Now copy the last phaseLen - 1 samples to the start of the state buffer.
** This prepares the state buffer for the next function call. */
/* Points to the start of the state buffer */
pStateCurnt = S->pState;
tapCnt = phaseLen - 1u;
while(tapCnt > 0u)
{
*pStateCurnt++ = *pState++;
/* Decrement the loop counter */
tapCnt--;
}
#endif /* #ifndef ARM_MATH_CM0 */
}
/**
* @} end of FIR_Interpolate group
*/