/* ----------------------------------------------------------------------
* Copyright (C) 2010 ARM Limited. All rights reserved.
*
* $Date: 15. February 2012
* $Revision: V1.1.0
*
* Project: CMSIS DSP Library
* Title: arm_conv_q7.c
*
* Description: Convolution of Q7 sequences.
*
* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
*
* Version 1.1.0 2012/02/15
* Updated with more optimizations, bug fixes and minor API changes.
*
* Version 1.0.11 2011/10/18
* Bug Fix in conv, correlation, partial convolution.
*
* 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"
/**
* @ingroup groupFilters
*/
/**
* @addtogroup Conv
* @{
*/
/**
* @brief Convolution of Q7 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. Length srcALen+srcBLen-1.
* @return none.
*
* @details
* Scaling and Overflow Behavior:
*
* \par
* The function is implemented using a 32-bit internal accumulator.
* Both the inputs are represented in 1.7 format and multiplications yield a 2.14 result.
* The 2.14 intermediate results are accumulated in a 32-bit accumulator in 18.14 format.
* This approach provides 17 guard bits and there is no risk of overflow as long as max(srcALen, srcBLen)<131072
.
* The 18.14 result is then truncated to 18.7 format by discarding the low 7 bits and then saturated to 1.7 format.
*
* \par
* Refer the function arm_conv_opt_q7()
for a faster implementation of this function.
*
*/
void arm_conv_q7(
q7_t * pSrcA,
uint32_t srcALen,
q7_t * pSrcB,
uint32_t srcBLen,
q7_t * pDst)
{
#ifndef ARM_MATH_CM0
/* Run the below code for Cortex-M4 and Cortex-M3 */
q7_t *pIn1; /* inputA pointer */
q7_t *pIn2; /* inputB pointer */
q7_t *pOut = pDst; /* output pointer */
q7_t *px; /* Intermediate inputA pointer */
q7_t *py; /* Intermediate inputB pointer */
q7_t *pSrc1, *pSrc2; /* Intermediate pointers */
q7_t x0, x1, x2, x3, c0, c1; /* Temporary variables to hold state and coefficient values */
q31_t sum, acc0, acc1, acc2, acc3; /* Accumulator */
q31_t input1, input2; /* Temporary input variables */
q15_t in1, in2; /* Temporary input variables */
uint32_t j, k, count, blkCnt, blockSize1, blockSize2, blockSize3; /* loop counter */
/* 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;
}
/* 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. */
/* The algorithm is implemented in three stages.
The loop counters of each stage is initiated here. */
blockSize1 = srcBLen - 1u;
blockSize2 = (srcALen - srcBLen) + 1u;
blockSize3 = blockSize1;
/* --------------------------
* 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 */
count = 1u;
/* Working pointer of inputA */
px = pIn1;
/* Working pointer of inputB */
py = pIn2;
/* ------------------------
* Stage1 process
* ----------------------*/
/* The first stage starts here */
while(blockSize1 > 0u)
{
/* 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] , x[1] */
in1 = (q15_t) * px++;
in2 = (q15_t) * px++;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* y[srcBLen - 1] , y[srcBLen - 2] */
in1 = (q15_t) * py--;
in2 = (q15_t) * py--;
input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* x[0] * y[srcBLen - 1] */
/* x[1] * y[srcBLen - 2] */
sum = __SMLAD(input1, input2, sum);
/* x[2] , x[3] */
in1 = (q15_t) * px++;
in2 = (q15_t) * px++;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* y[srcBLen - 3] , y[srcBLen - 4] */
in1 = (q15_t) * py--;
in2 = (q15_t) * py--;
input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* x[2] * y[srcBLen - 3] */
/* x[3] * y[srcBLen - 4] */
sum = __SMLAD(input1, input2, sum);
/* 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-accumulates */
sum += ((q15_t) * px++ * *py--);
/* Decrement the loop counter */
k--;
}
/* Store the result in the accumulator in the destination buffer. */
*pOut++ = (q7_t) (__SSAT(sum >> 7u, 8));
/* Update the inputA and inputB pointers for next MAC calculation */
py = pIn2 + count;
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 */
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 blockSize2, by 4 */
blkCnt = blockSize2 >> 2u;
while(blkCnt > 0u)
{
/* Set all accumulators to zero */
acc0 = 0;
acc1 = 0;
acc2 = 0;
acc3 = 0;
/* read x[0], x[1], x[2] samples */
x0 = *(px++);
x1 = *(px++);
x2 = *(px++);
/* 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. */
do
{
/* Read y[srcBLen - 1] sample */
c0 = *(py--);
/* Read y[srcBLen - 2] sample */
c1 = *(py--);
/* Read x[3] sample */
x3 = *(px++);
/* x[0] and x[1] are packed */
in1 = (q15_t) x0;
in2 = (q15_t) x1;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* y[srcBLen - 1] and y[srcBLen - 2] are packed */
in1 = (q15_t) c0;
in2 = (q15_t) c1;
input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* acc0 += x[0] * y[srcBLen - 1] + x[1] * y[srcBLen - 2] */
acc0 = __SMLAD(input1, input2, acc0);
/* x[1] and x[2] are packed */
in1 = (q15_t) x1;
in2 = (q15_t) x2;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* acc1 += x[1] * y[srcBLen - 1] + x[2] * y[srcBLen - 2] */
acc1 = __SMLAD(input1, input2, acc1);
/* x[2] and x[3] are packed */
in1 = (q15_t) x2;
in2 = (q15_t) x3;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* acc2 += x[2] * y[srcBLen - 1] + x[3] * y[srcBLen - 2] */
acc2 = __SMLAD(input1, input2, acc2);
/* Read x[4] sample */
x0 = *(px++);
/* x[3] and x[4] are packed */
in1 = (q15_t) x3;
in2 = (q15_t) x0;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* acc3 += x[3] * y[srcBLen - 1] + x[4] * y[srcBLen - 2] */
acc3 = __SMLAD(input1, input2, acc3);
/* Read y[srcBLen - 3] sample */
c0 = *(py--);
/* Read y[srcBLen - 4] sample */
c1 = *(py--);
/* Read x[5] sample */
x1 = *(px++);
/* x[2] and x[3] are packed */
in1 = (q15_t) x2;
in2 = (q15_t) x3;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* y[srcBLen - 3] and y[srcBLen - 4] are packed */
in1 = (q15_t) c0;
in2 = (q15_t) c1;
input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* acc0 += x[2] * y[srcBLen - 3] + x[3] * y[srcBLen - 4] */
acc0 = __SMLAD(input1, input2, acc0);
/* x[3] and x[4] are packed */
in1 = (q15_t) x3;
in2 = (q15_t) x0;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* acc1 += x[3] * y[srcBLen - 3] + x[4] * y[srcBLen - 4] */
acc1 = __SMLAD(input1, input2, acc1);
/* x[4] and x[5] are packed */
in1 = (q15_t) x0;
in2 = (q15_t) x1;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* acc2 += x[4] * y[srcBLen - 3] + x[5] * y[srcBLen - 4] */
acc2 = __SMLAD(input1, input2, acc2);
/* Read x[6] sample */
x2 = *(px++);
/* x[5] and x[6] are packed */
in1 = (q15_t) x1;
in2 = (q15_t) x2;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* acc3 += x[5] * y[srcBLen - 3] + x[6] * y[srcBLen - 4] */
acc3 = __SMLAD(input1, input2, acc3);
} while(--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)
{
/* Read y[srcBLen - 5] sample */
c0 = *(py--);
/* Read x[7] sample */
x3 = *(px++);
/* Perform the multiply-accumulates */
/* acc0 += x[4] * y[srcBLen - 5] */
acc0 += ((q15_t) x0 * c0);
/* acc1 += x[5] * y[srcBLen - 5] */
acc1 += ((q15_t) x1 * c0);
/* acc2 += x[6] * y[srcBLen - 5] */
acc2 += ((q15_t) x2 * c0);
/* acc3 += x[7] * y[srcBLen - 5] */
acc3 += ((q15_t) x3 * c0);
/* Reuse the present samples for the next MAC */
x0 = x1;
x1 = x2;
x2 = x3;
/* Decrement the loop counter */
k--;
}
/* Store the result in the accumulator in the destination buffer. */
*pOut++ = (q7_t) (__SSAT(acc0 >> 7u, 8));
*pOut++ = (q7_t) (__SSAT(acc1 >> 7u, 8));
*pOut++ = (q7_t) (__SSAT(acc2 >> 7u, 8));
*pOut++ = (q7_t) (__SSAT(acc3 >> 7u, 8));
/* Increment the pointer pIn1 index, count by 4 */
count += 4u;
/* Update the inputA and inputB pointers for next MAC calculation */
px = pIn1 + count;
py = pSrc2;
/* Decrement the loop counter */
blkCnt--;
}
/* If the blockSize2 is not a multiple of 4, compute any remaining output samples here.
** No loop unrolling is used. */
blkCnt = blockSize2 % 0x4u;
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)
{
/* Reading two inputs of SrcA buffer and packing */
in1 = (q15_t) * px++;
in2 = (q15_t) * px++;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* Reading two inputs of SrcB buffer and packing */
in1 = (q15_t) * py--;
in2 = (q15_t) * py--;
input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* Perform the multiply-accumulates */
sum = __SMLAD(input1, input2, sum);
/* Reading two inputs of SrcA buffer and packing */
in1 = (q15_t) * px++;
in2 = (q15_t) * px++;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* Reading two inputs of SrcB buffer and packing */
in1 = (q15_t) * py--;
in2 = (q15_t) * py--;
input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* Perform the multiply-accumulates */
sum = __SMLAD(input1, input2, sum);
/* 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-accumulates */
sum += ((q15_t) * px++ * *py--);
/* Decrement the loop counter */
k--;
}
/* Store the result in the accumulator in the destination buffer. */
*pOut++ = (q7_t) (__SSAT(sum >> 7u, 8));
/* Increment the pointer pIn1 index, count by 1 */
count++;
/* Update the inputA and inputB pointers for next MAC calculation */
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 = 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 += ((q15_t) * px++ * *py--);
/* Decrement the loop counter */
k--;
}
/* Store the result in the accumulator in the destination buffer. */
*pOut++ = (q7_t) (__SSAT(sum >> 7u, 8));
/* Increment the MAC count */
count++;
/* Update the inputA and inputB pointers for next MAC calculation */
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 */
/* 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 > 0u)
{
/* Accumulator is made zero for every iteration */
sum = 0;
/* Apply loop unrolling and compute 4 MACs simultaneously. */
k = blockSize3 >> 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)
{
/* Reading two inputs, x[srcALen - srcBLen + 1] and x[srcALen - srcBLen + 2] of SrcA buffer and packing */
in1 = (q15_t) * px++;
in2 = (q15_t) * px++;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* Reading two inputs, y[srcBLen - 1] and y[srcBLen - 2] of SrcB buffer and packing */
in1 = (q15_t) * py--;
in2 = (q15_t) * py--;
input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* sum += x[srcALen - srcBLen + 1] * y[srcBLen - 1] */
/* sum += x[srcALen - srcBLen + 2] * y[srcBLen - 2] */
sum = __SMLAD(input1, input2, sum);
/* Reading two inputs, x[srcALen - srcBLen + 3] and x[srcALen - srcBLen + 4] of SrcA buffer and packing */
in1 = (q15_t) * px++;
in2 = (q15_t) * px++;
input1 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* Reading two inputs, y[srcBLen - 3] and y[srcBLen - 4] of SrcB buffer and packing */
in1 = (q15_t) * py--;
in2 = (q15_t) * py--;
input2 = ((q31_t) in1 & 0x0000FFFF) | ((q31_t) in2 << 16u);
/* sum += x[srcALen - srcBLen + 3] * y[srcBLen - 3] */
/* sum += x[srcALen - srcBLen + 4] * y[srcBLen - 4] */
sum = __SMLAD(input1, input2, sum);
/* 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 = blockSize3 % 0x4u;
while(k > 0u)
{
/* Perform the multiply-accumulates */
sum += ((q15_t) * px++ * *py--);
/* Decrement the loop counter */
k--;
}
/* Store the result in the accumulator in the destination buffer. */
*pOut++ = (q7_t) (__SSAT(sum >> 7u, 8));
/* Update the inputA and inputB pointers for next MAC calculation */
px = ++pSrc1;
py = pSrc2;
/* Decrement the loop counter */
blockSize3--;
}
#else
/* Run the below code for Cortex-M0 */
q7_t *pIn1 = pSrcA; /* input pointer */
q7_t *pIn2 = pSrcB; /* coefficient pointer */
q31_t sum; /* Accumulator */
uint32_t i, j; /* loop counter */
/* Loop to calculate output of convolution for output length number of times */
for (i = 0; i < (srcALen + srcBLen - 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 += (q15_t) pIn1[j] * (pIn2[i - j]);
}
}
/* Store the output in the destination buffer */
pDst[i] = (q7_t) __SSAT((sum >> 7u), 8u);
}
#endif /* #ifndef ARM_MATH_CM0 */
}
/**
* @} end of Conv group
*/