pigweed / third_party / github / STMicroelectronics / cmsis_core / cb6d9400754e6c9050487dfa573949b61152ac99 / . / DSP / Source / FilteringFunctions / arm_conv_partial_q31.c

/* ---------------------------------------------------------------------- | |

* Project: CMSIS DSP Library | |

* Title: arm_conv_partial_q31.c | |

* Description: Partial convolution of Q31 sequences | |

* | |

* $Date: 27. January 2017 | |

* $Revision: V.1.5.1 | |

* | |

* Target Processor: Cortex-M cores | |

* -------------------------------------------------------------------- */ | |

/* | |

* Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved. | |

* | |

* SPDX-License-Identifier: Apache-2.0 | |

* | |

* Licensed under the Apache License, Version 2.0 (the License); you may | |

* not use this file except in compliance with the License. | |

* You may obtain a copy of the License at | |

* | |

* www.apache.org/licenses/LICENSE-2.0 | |

* | |

* Unless required by applicable law or agreed to in writing, software | |

* distributed under the License is distributed on an AS IS BASIS, WITHOUT | |

* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. | |

* See the License for the specific language governing permissions and | |

* limitations under the License. | |

*/ | |

#include "arm_math.h" | |

/** | |

* @ingroup groupFilters | |

*/ | |

/** | |

* @addtogroup PartialConv | |

* @{ | |

*/ | |

/** | |

* @brief Partial convolution of Q31 sequences. | |

* @param[in] *pSrcA points to the first input sequence. | |

* @param[in] srcALen length of the first input sequence. | |

* @param[in] *pSrcB points to the second input sequence. | |

* @param[in] srcBLen length of the second input sequence. | |

* @param[out] *pDst points to the location where the output result is written. | |

* @param[in] firstIndex is the first output sample to start with. | |

* @param[in] numPoints is the number of output points to be computed. | |

* @return Returns either ARM_MATH_SUCCESS if the function completed correctly or ARM_MATH_ARGUMENT_ERROR if the requested subset is not in the range [0 srcALen+srcBLen-2]. | |

* | |

* See <code>arm_conv_partial_fast_q31()</code> for a faster but less precise implementation of this function for Cortex-M3 and Cortex-M4. | |

*/ | |

arm_status arm_conv_partial_q31( | |

q31_t * pSrcA, | |

uint32_t srcALen, | |

q31_t * pSrcB, | |

uint32_t srcBLen, | |

q31_t * pDst, | |

uint32_t firstIndex, | |

uint32_t numPoints) | |

{ | |

#if defined (ARM_MATH_DSP) | |

/* Run the below code for Cortex-M4 and Cortex-M3 */ | |

q31_t *pIn1; /* inputA pointer */ | |

q31_t *pIn2; /* inputB pointer */ | |

q31_t *pOut = pDst; /* output pointer */ | |

q31_t *px; /* Intermediate inputA pointer */ | |

q31_t *py; /* Intermediate inputB pointer */ | |

q31_t *pSrc1, *pSrc2; /* Intermediate pointers */ | |

q63_t sum, acc0, acc1, acc2; /* Accumulator */ | |

q31_t x0, x1, x2, c0; | |

uint32_t j, k, count, check, blkCnt; | |

int32_t blockSize1, blockSize2, blockSize3; /* loop counter */ | |

arm_status status; /* status of Partial convolution */ | |

/* Check for range of output samples to be calculated */ | |

if ((firstIndex + numPoints) > ((srcALen + (srcBLen - 1U)))) | |

{ | |

/* Set status as ARM_MATH_ARGUMENT_ERROR */ | |

status = ARM_MATH_ARGUMENT_ERROR; | |

} | |

else | |

{ | |

/* The algorithm implementation is based on the lengths of the inputs. */ | |

/* srcB is always made to slide across srcA. */ | |

/* So srcBLen is always considered as shorter or equal to srcALen */ | |

if (srcALen >= srcBLen) | |

{ | |

/* Initialization of inputA pointer */ | |

pIn1 = pSrcA; | |

/* Initialization of inputB pointer */ | |

pIn2 = pSrcB; | |

} | |

else | |

{ | |

/* Initialization of inputA pointer */ | |

pIn1 = pSrcB; | |

/* Initialization of inputB pointer */ | |

pIn2 = pSrcA; | |

/* srcBLen is always considered as shorter or equal to srcALen */ | |

j = srcBLen; | |

srcBLen = srcALen; | |

srcALen = j; | |

} | |

/* Conditions to check which loopCounter holds | |

* the first and last indices of the output samples to be calculated. */ | |

check = firstIndex + numPoints; | |

blockSize3 = ((int32_t)check > (int32_t)srcALen) ? (int32_t)check - (int32_t)srcALen : 0; | |

blockSize3 = ((int32_t)firstIndex > (int32_t)srcALen - 1) ? blockSize3 - (int32_t)firstIndex + (int32_t)srcALen : blockSize3; | |

blockSize1 = (((int32_t) srcBLen - 1) - (int32_t) firstIndex); | |

blockSize1 = (blockSize1 > 0) ? ((check > (srcBLen - 1U)) ? blockSize1 : | |

(int32_t) numPoints) : 0; | |

blockSize2 = (int32_t) check - ((blockSize3 + blockSize1) + | |

(int32_t) firstIndex); | |

blockSize2 = (blockSize2 > 0) ? blockSize2 : 0; | |

/* conv(x,y) at n = x[n] * y[0] + x[n-1] * y[1] + x[n-2] * y[2] + ...+ x[n-N+1] * y[N -1] */ | |

/* The function is internally | |

* divided into three stages according to the number of multiplications that has to be | |

* taken place between inputA samples and inputB samples. In the first stage of the | |

* algorithm, the multiplications increase by one for every iteration. | |

* In the second stage of the algorithm, srcBLen number of multiplications are done. | |

* In the third stage of the algorithm, the multiplications decrease by one | |

* for every iteration. */ | |

/* Set the output pointer to point to the firstIndex | |

* of the output sample to be calculated. */ | |

pOut = pDst + firstIndex; | |

/* -------------------------- | |

* Initializations of stage1 | |

* -------------------------*/ | |

/* sum = x[0] * y[0] | |

* sum = x[0] * y[1] + x[1] * y[0] | |

* .... | |

* sum = x[0] * y[srcBlen - 1] + x[1] * y[srcBlen - 2] +...+ x[srcBLen - 1] * y[0] | |

*/ | |

/* In this stage the MAC operations are increased by 1 for every iteration. | |

The count variable holds the number of MAC operations performed. | |

Since the partial convolution starts from firstIndex | |

Number of Macs to be performed is firstIndex + 1 */ | |

count = 1U + firstIndex; | |

/* Working pointer of inputA */ | |

px = pIn1; | |

/* Working pointer of inputB */ | |

pSrc2 = pIn2 + firstIndex; | |

py = pSrc2; | |

/* ------------------------ | |

* Stage1 process | |

* ----------------------*/ | |

/* The first loop starts here */ | |

while (blockSize1 > 0) | |

{ | |

/* Accumulator is made zero for every iteration */ | |

sum = 0; | |

/* Apply loop unrolling and compute 4 MACs simultaneously. */ | |

k = count >> 2U; | |

/* First part of the processing with loop unrolling. Compute 4 MACs at a time. | |

** a second loop below computes MACs for the remaining 1 to 3 samples. */ | |

while (k > 0U) | |

{ | |

/* x[0] * y[srcBLen - 1] */ | |

sum += (q63_t) * px++ * (*py--); | |

/* x[1] * y[srcBLen - 2] */ | |

sum += (q63_t) * px++ * (*py--); | |

/* x[2] * y[srcBLen - 3] */ | |

sum += (q63_t) * px++ * (*py--); | |

/* x[3] * y[srcBLen - 4] */ | |

sum += (q63_t) * px++ * (*py--); | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* If the count is not a multiple of 4, compute any remaining MACs here. | |

** No loop unrolling is used. */ | |

k = count % 0x4U; | |

while (k > 0U) | |

{ | |

/* Perform the multiply-accumulate */ | |

sum += (q63_t) * px++ * (*py--); | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* Store the result in the accumulator in the destination buffer. */ | |

*pOut++ = (q31_t) (sum >> 31); | |

/* Update the inputA and inputB pointers for next MAC calculation */ | |

py = ++pSrc2; | |

px = pIn1; | |

/* Increment the MAC count */ | |

count++; | |

/* Decrement the loop counter */ | |

blockSize1--; | |

} | |

/* -------------------------- | |

* Initializations of stage2 | |

* ------------------------*/ | |

/* sum = x[0] * y[srcBLen-1] + x[1] * y[srcBLen-2] +...+ x[srcBLen-1] * y[0] | |

* sum = x[1] * y[srcBLen-1] + x[2] * y[srcBLen-2] +...+ x[srcBLen] * y[0] | |

* .... | |

* sum = x[srcALen-srcBLen-2] * y[srcBLen-1] + x[srcALen] * y[srcBLen-2] +...+ x[srcALen-1] * y[0] | |

*/ | |

/* Working pointer of inputA */ | |

if ((int32_t)firstIndex - (int32_t)srcBLen + 1 > 0) | |

{ | |

px = pIn1 + firstIndex - srcBLen + 1; | |

} | |

else | |

{ | |

px = pIn1; | |

} | |

/* Working pointer of inputB */ | |

pSrc2 = pIn2 + (srcBLen - 1U); | |

py = pSrc2; | |

/* count is index by which the pointer pIn1 to be incremented */ | |

count = 0U; | |

/* ------------------- | |

* Stage2 process | |

* ------------------*/ | |

/* Stage2 depends on srcBLen as in this stage srcBLen number of MACS are performed. | |

* So, to loop unroll over blockSize2, | |

* srcBLen should be greater than or equal to 4 */ | |

if (srcBLen >= 4U) | |

{ | |

/* Loop unroll over blkCnt */ | |

blkCnt = blockSize2 / 3; | |

while (blkCnt > 0U) | |

{ | |

/* Set all accumulators to zero */ | |

acc0 = 0; | |

acc1 = 0; | |

acc2 = 0; | |

/* read x[0], x[1] samples */ | |

x0 = *(px++); | |

x1 = *(px++); | |

/* Apply loop unrolling and compute 3 MACs simultaneously. */ | |

k = srcBLen / 3; | |

/* First part of the processing with loop unrolling. Compute 3 MACs at a time. | |

** a second loop below computes MACs for the remaining 1 to 2 samples. */ | |

do | |

{ | |

/* Read y[srcBLen - 1] sample */ | |

c0 = *(py); | |

/* Read x[2] sample */ | |

x2 = *(px); | |

/* Perform the multiply-accumulates */ | |

/* acc0 += x[0] * y[srcBLen - 1] */ | |

acc0 += (q63_t) x0 *c0; | |

/* acc1 += x[1] * y[srcBLen - 1] */ | |

acc1 += (q63_t) x1 *c0; | |

/* acc2 += x[2] * y[srcBLen - 1] */ | |

acc2 += (q63_t) x2 *c0; | |

/* Read y[srcBLen - 2] sample */ | |

c0 = *(py - 1U); | |

/* Read x[3] sample */ | |

x0 = *(px + 1U); | |

/* Perform the multiply-accumulate */ | |

/* acc0 += x[1] * y[srcBLen - 2] */ | |

acc0 += (q63_t) x1 *c0; | |

/* acc1 += x[2] * y[srcBLen - 2] */ | |

acc1 += (q63_t) x2 *c0; | |

/* acc2 += x[3] * y[srcBLen - 2] */ | |

acc2 += (q63_t) x0 *c0; | |

/* Read y[srcBLen - 3] sample */ | |

c0 = *(py - 2U); | |

/* Read x[4] sample */ | |

x1 = *(px + 2U); | |

/* Perform the multiply-accumulates */ | |

/* acc0 += x[2] * y[srcBLen - 3] */ | |

acc0 += (q63_t) x2 *c0; | |

/* acc1 += x[3] * y[srcBLen - 2] */ | |

acc1 += (q63_t) x0 *c0; | |

/* acc2 += x[4] * y[srcBLen - 2] */ | |

acc2 += (q63_t) x1 *c0; | |

px += 3U; | |

py -= 3U; | |

} while (--k); | |

/* If the srcBLen is not a multiple of 3, compute any remaining MACs here. | |

** No loop unrolling is used. */ | |

k = srcBLen - (3 * (srcBLen / 3)); | |

while (k > 0U) | |

{ | |

/* Read y[srcBLen - 5] sample */ | |

c0 = *(py--); | |

/* Read x[7] sample */ | |

x2 = *(px++); | |

/* Perform the multiply-accumulates */ | |

/* acc0 += x[4] * y[srcBLen - 5] */ | |

acc0 += (q63_t) x0 *c0; | |

/* acc1 += x[5] * y[srcBLen - 5] */ | |

acc1 += (q63_t) x1 *c0; | |

/* acc2 += x[6] * y[srcBLen - 5] */ | |

acc2 += (q63_t) x2 *c0; | |

/* Reuse the present samples for the next MAC */ | |

x0 = x1; | |

x1 = x2; | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* Store the result in the accumulator in the destination buffer. */ | |

*pOut++ = (q31_t) (acc0 >> 31); | |

*pOut++ = (q31_t) (acc1 >> 31); | |

*pOut++ = (q31_t) (acc2 >> 31); | |

/* Increment the pointer pIn1 index, count by 3 */ | |

count += 3U; | |

/* Update the inputA and inputB pointers for next MAC calculation */ | |

if ((int32_t)firstIndex - (int32_t)srcBLen + 1 > 0) | |

{ | |

px = pIn1 + firstIndex - srcBLen + 1 + count; | |

} | |

else | |

{ | |

px = pIn1 + count; | |

} | |

py = pSrc2; | |

/* Decrement the loop counter */ | |

blkCnt--; | |

} | |

/* If the blockSize2 is not a multiple of 3, compute any remaining output samples here. | |

** No loop unrolling is used. */ | |

blkCnt = blockSize2 - 3 * (blockSize2 / 3); | |

while (blkCnt > 0U) | |

{ | |

/* Accumulator is made zero for every iteration */ | |

sum = 0; | |

/* Apply loop unrolling and compute 4 MACs simultaneously. */ | |

k = srcBLen >> 2U; | |

/* First part of the processing with loop unrolling. Compute 4 MACs at a time. | |

** a second loop below computes MACs for the remaining 1 to 3 samples. */ | |

while (k > 0U) | |

{ | |

/* Perform the multiply-accumulates */ | |

sum += (q63_t) * px++ * (*py--); | |

sum += (q63_t) * px++ * (*py--); | |

sum += (q63_t) * px++ * (*py--); | |

sum += (q63_t) * px++ * (*py--); | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* If the srcBLen is not a multiple of 4, compute any remaining MACs here. | |

** No loop unrolling is used. */ | |

k = srcBLen % 0x4U; | |

while (k > 0U) | |

{ | |

/* Perform the multiply-accumulate */ | |

sum += (q63_t) * px++ * (*py--); | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* Store the result in the accumulator in the destination buffer. */ | |

*pOut++ = (q31_t) (sum >> 31); | |

/* Increment the MAC count */ | |

count++; | |

/* Update the inputA and inputB pointers for next MAC calculation */ | |

if ((int32_t)firstIndex - (int32_t)srcBLen + 1 > 0) | |

{ | |

px = pIn1 + firstIndex - srcBLen + 1 + count; | |

} | |

else | |

{ | |

px = pIn1 + count; | |

} | |

py = pSrc2; | |

/* Decrement the loop counter */ | |

blkCnt--; | |

} | |

} | |

else | |

{ | |

/* If the srcBLen is not a multiple of 4, | |

* the blockSize2 loop cannot be unrolled by 4 */ | |

blkCnt = (uint32_t) blockSize2; | |

while (blkCnt > 0U) | |

{ | |

/* Accumulator is made zero for every iteration */ | |

sum = 0; | |

/* srcBLen number of MACS should be performed */ | |

k = srcBLen; | |

while (k > 0U) | |

{ | |

/* Perform the multiply-accumulate */ | |

sum += (q63_t) * px++ * (*py--); | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* Store the result in the accumulator in the destination buffer. */ | |

*pOut++ = (q31_t) (sum >> 31); | |

/* Increment the MAC count */ | |

count++; | |

/* Update the inputA and inputB pointers for next MAC calculation */ | |

if ((int32_t)firstIndex - (int32_t)srcBLen + 1 > 0) | |

{ | |

px = pIn1 + firstIndex - srcBLen + 1 + count; | |

} | |

else | |

{ | |

px = pIn1 + count; | |

} | |

py = pSrc2; | |

/* Decrement the loop counter */ | |

blkCnt--; | |

} | |

} | |

/* -------------------------- | |

* Initializations of stage3 | |

* -------------------------*/ | |

/* sum += x[srcALen-srcBLen+1] * y[srcBLen-1] + x[srcALen-srcBLen+2] * y[srcBLen-2] +...+ x[srcALen-1] * y[1] | |

* sum += x[srcALen-srcBLen+2] * y[srcBLen-1] + x[srcALen-srcBLen+3] * y[srcBLen-2] +...+ x[srcALen-1] * y[2] | |

* .... | |

* sum += x[srcALen-2] * y[srcBLen-1] + x[srcALen-1] * y[srcBLen-2] | |

* sum += x[srcALen-1] * y[srcBLen-1] | |

*/ | |

/* In this stage the MAC operations are decreased by 1 for every iteration. | |

The blockSize3 variable holds the number of MAC operations performed */ | |

count = srcBLen - 1U; | |

/* Working pointer of inputA */ | |

pSrc1 = (pIn1 + srcALen) - (srcBLen - 1U); | |

px = pSrc1; | |

/* Working pointer of inputB */ | |

pSrc2 = pIn2 + (srcBLen - 1U); | |

py = pSrc2; | |

/* ------------------- | |

* Stage3 process | |

* ------------------*/ | |

while (blockSize3 > 0) | |

{ | |

/* Accumulator is made zero for every iteration */ | |

sum = 0; | |

/* Apply loop unrolling and compute 4 MACs simultaneously. */ | |

k = count >> 2U; | |

/* First part of the processing with loop unrolling. Compute 4 MACs at a time. | |

** a second loop below computes MACs for the remaining 1 to 3 samples. */ | |

while (k > 0U) | |

{ | |

sum += (q63_t) * px++ * (*py--); | |

sum += (q63_t) * px++ * (*py--); | |

sum += (q63_t) * px++ * (*py--); | |

sum += (q63_t) * px++ * (*py--); | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* If the blockSize3 is not a multiple of 4, compute any remaining MACs here. | |

** No loop unrolling is used. */ | |

k = count % 0x4U; | |

while (k > 0U) | |

{ | |

/* Perform the multiply-accumulate */ | |

sum += (q63_t) * px++ * (*py--); | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* Store the result in the accumulator in the destination buffer. */ | |

*pOut++ = (q31_t) (sum >> 31); | |

/* Update the inputA and inputB pointers for next MAC calculation */ | |

px = ++pSrc1; | |

py = pSrc2; | |

/* Decrement the MAC count */ | |

count--; | |

/* Decrement the loop counter */ | |

blockSize3--; | |

} | |

/* set status as ARM_MATH_SUCCESS */ | |

status = ARM_MATH_SUCCESS; | |

} | |

/* Return to application */ | |

return (status); | |

#else | |

/* Run the below code for Cortex-M0 */ | |

q31_t *pIn1 = pSrcA; /* inputA pointer */ | |

q31_t *pIn2 = pSrcB; /* inputB pointer */ | |

q63_t sum; /* Accumulator */ | |

uint32_t i, j; /* loop counters */ | |

arm_status status; /* status of Partial convolution */ | |

/* Check for range of output samples to be calculated */ | |

if ((firstIndex + numPoints) > ((srcALen + (srcBLen - 1U)))) | |

{ | |

/* Set status as ARM_ARGUMENT_ERROR */ | |

status = ARM_MATH_ARGUMENT_ERROR; | |

} | |

else | |

{ | |

/* Loop to calculate convolution for output length number of values */ | |

for (i = firstIndex; i <= (firstIndex + numPoints - 1); i++) | |

{ | |

/* Initialize sum with zero to carry on MAC operations */ | |

sum = 0; | |

/* Loop to perform MAC operations according to convolution equation */ | |

for (j = 0; j <= i; j++) | |

{ | |

/* Check the array limitations */ | |

if (((i - j) < srcBLen) && (j < srcALen)) | |

{ | |

/* z[i] += x[i-j] * y[j] */ | |

sum += ((q63_t) pIn1[j] * (pIn2[i - j])); | |

} | |

} | |

/* Store the output in the destination buffer */ | |

pDst[i] = (q31_t) (sum >> 31U); | |

} | |

/* set status as ARM_SUCCESS as there are no argument errors */ | |

status = ARM_MATH_SUCCESS; | |

} | |

return (status); | |

#endif /* #if defined (ARM_MATH_DSP) */ | |

} | |

/** | |

* @} end of PartialConv group | |

*/ |