| /*----------------------------------------------------------------------------- |
| * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| * |
| * $Date: 19. March 2015 |
| * $Revision: V.1.4.5 |
| * |
| * Project: CMSIS DSP Library |
| * Title: arm_fir_interpolate_q15.c |
| * |
| * Description: Q15 FIR interpolation. |
| * |
| * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * - Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * - Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * - Neither the name of ARM LIMITED nor the names of its contributors |
| * may be used to endorse or promote products derived from this |
| * software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
| * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
| * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
| * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
| * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
| * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER |
| * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
| * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| * POSSIBILITY OF SUCH DAMAGE. |
| * ---------------------------------------------------------------------------*/ |
| |
| #include "arm_math.h" |
| |
| /** |
| * @ingroup groupFilters |
| */ |
| |
| /** |
| * @addtogroup FIR_Interpolate |
| * @{ |
| */ |
| |
| /** |
| * @brief Processing function for the Q15 FIR interpolator. |
| * @param[in] *S points to an instance of the Q15 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. |
| * |
| * <b>Scaling and Overflow Behavior:</b> |
| * \par |
| * The function is implemented using a 64-bit internal accumulator. |
| * Both coefficients and state variables are represented in 1.15 format and multiplications yield a 2.30 result. |
| * The 2.30 intermediate results are accumulated in a 64-bit accumulator in 34.30 format. |
| * There is no risk of internal overflow with this approach and the full precision of intermediate multiplications is preserved. |
| * After all additions have been performed, the accumulator is truncated to 34.15 format by discarding low 15 bits. |
| * Lastly, the accumulator is saturated to yield a result in 1.15 format. |
| */ |
| |
| #ifndef ARM_MATH_CM0_FAMILY |
| |
| /* Run the below code for Cortex-M4 and Cortex-M3 */ |
| |
| void arm_fir_interpolate_q15( |
| const arm_fir_interpolate_instance_q15 * S, |
| q15_t * pSrc, |
| q15_t * pDst, |
| uint32_t blockSize) |
| { |
| q15_t *pState = S->pState; /* State pointer */ |
| q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| q15_t *pStateCurnt; /* Points to the current sample of the state */ |
| q15_t *ptr1, *ptr2; /* Temporary pointers for state and coefficient buffers */ |
| q63_t sum0; /* Accumulators */ |
| q15_t x0, c0; /* Temporary variables to hold state and coefficient values */ |
| uint32_t i, blkCnt, j, tapCnt; /* Loop counters */ |
| uint16_t phaseLen = S->phaseLength; /* Length of each polyphase filter component */ |
| uint32_t blkCntN2; |
| q63_t acc0, acc1; |
| q15_t x1; |
| |
| /* 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 + ((q31_t) phaseLen - 1); |
| |
| /* Initialise blkCnt */ |
| blkCnt = blockSize / 2; |
| blkCntN2 = blockSize - (2 * blkCnt); |
| |
| /* Samples loop unrolled by 2 */ |
| while(blkCnt > 0u) |
| { |
| /* Copy new input sample into the state buffer */ |
| *pStateCurnt++ = *pSrc++; |
| *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 */ |
| acc0 = 0; |
| acc1 = 0; |
| |
| /* 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; |
| |
| x0 = *(ptr1++); |
| |
| while(tapCnt > 0u) |
| { |
| |
| /* Read the input sample */ |
| x1 = *(ptr1++); |
| |
| /* Read the coefficient */ |
| c0 = *(ptr2); |
| |
| /* Perform the multiply-accumulate */ |
| acc0 += (q63_t) x0 *c0; |
| acc1 += (q63_t) x1 *c0; |
| |
| |
| /* Read the coefficient */ |
| c0 = *(ptr2 + S->L); |
| |
| /* Read the input sample */ |
| x0 = *(ptr1++); |
| |
| /* Perform the multiply-accumulate */ |
| acc0 += (q63_t) x1 *c0; |
| acc1 += (q63_t) x0 *c0; |
| |
| |
| /* Read the coefficient */ |
| c0 = *(ptr2 + S->L * 2); |
| |
| /* Read the input sample */ |
| x1 = *(ptr1++); |
| |
| /* Perform the multiply-accumulate */ |
| acc0 += (q63_t) x0 *c0; |
| acc1 += (q63_t) x1 *c0; |
| |
| /* Read the coefficient */ |
| c0 = *(ptr2 + S->L * 3); |
| |
| /* Read the input sample */ |
| x0 = *(ptr1++); |
| |
| /* Perform the multiply-accumulate */ |
| acc0 += (q63_t) x1 *c0; |
| acc1 += (q63_t) x0 *c0; |
| |
| |
| /* 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 += 4 * S->L; |
| |
| /* 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) |
| { |
| |
| /* Read the input sample */ |
| x1 = *(ptr1++); |
| |
| /* Read the coefficient */ |
| c0 = *(ptr2); |
| |
| /* Perform the multiply-accumulate */ |
| acc0 += (q63_t) x0 *c0; |
| acc1 += (q63_t) x1 *c0; |
| |
| /* Increment the coefficient pointer by interpolation factor times. */ |
| ptr2 += S->L; |
| |
| /* update states for next sample processing */ |
| x0 = x1; |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| /* The result is in the accumulator, store in the destination buffer. */ |
| *pDst = (q15_t) (__SSAT((acc0 >> 15), 16)); |
| *(pDst + S->L) = (q15_t) (__SSAT((acc1 >> 15), 16)); |
| |
| pDst++; |
| |
| /* 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 + 2; |
| |
| pDst += S->L; |
| |
| /* Decrement the loop counter */ |
| blkCnt--; |
| } |
| |
| /* If the blockSize is not a multiple of 2, compute any remaining output samples here. |
| ** No loop unrolling is used. */ |
| blkCnt = blkCntN2; |
| |
| /* 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; |
| |
| /* 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 >> 2; |
| 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 += (q63_t) 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 += (q63_t) 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 += (q63_t) 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 += (q63_t) x0 *c0; |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| /* If the polyPhase length is not a multiple of 4, compute the remaining filter taps */ |
| tapCnt = phaseLen & 0x3u; |
| |
| while(tapCnt > 0u) |
| { |
| /* 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 += (q63_t) x0 *c0; |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| /* The result is in the accumulator, store in the destination buffer. */ |
| *pDst++ = (q15_t) (__SSAT((sum0 >> 15), 16)); |
| |
| 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; |
| |
| i = ((uint32_t) phaseLen - 1u) >> 2u; |
| |
| /* copy data */ |
| while(i > 0u) |
| { |
| #ifndef UNALIGNED_SUPPORT_DISABLE |
| |
| *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; |
| *__SIMD32(pStateCurnt)++ = *__SIMD32(pState)++; |
| |
| #else |
| |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| *pStateCurnt++ = *pState++; |
| |
| #endif /* #ifndef UNALIGNED_SUPPORT_DISABLE */ |
| |
| /* Decrement the loop counter */ |
| i--; |
| } |
| |
| i = ((uint32_t) phaseLen - 1u) % 0x04u; |
| |
| while(i > 0u) |
| { |
| *pStateCurnt++ = *pState++; |
| |
| /* Decrement the loop counter */ |
| i--; |
| } |
| } |
| |
| #else |
| |
| /* Run the below code for Cortex-M0 */ |
| |
| void arm_fir_interpolate_q15( |
| const arm_fir_interpolate_instance_q15 * S, |
| q15_t * pSrc, |
| q15_t * pDst, |
| uint32_t blockSize) |
| { |
| q15_t *pState = S->pState; /* State pointer */ |
| q15_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */ |
| q15_t *pStateCurnt; /* Points to the current sample of the state */ |
| q15_t *ptr1, *ptr2; /* Temporary pointers for state and coefficient buffers */ |
| q63_t sum; /* Accumulator */ |
| q15_t x0, c0; /* Temporary variables to hold state and coefficient values */ |
| uint32_t i, blkCnt, tapCnt; /* Loop counters */ |
| uint16_t phaseLen = S->phaseLength; /* 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; |
| |
| /* Initialize state pointer */ |
| ptr1 = pState; |
| |
| /* Initialize coefficient pointer */ |
| ptr2 = pCoeffs + (i - 1u); |
| |
| /* Loop over the polyPhase length */ |
| tapCnt = (uint32_t) phaseLen; |
| |
| while(tapCnt > 0u) |
| { |
| /* 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 */ |
| sum += ((q31_t) x0 * c0); |
| |
| /* Decrement the loop counter */ |
| tapCnt--; |
| } |
| |
| /* Store the result after converting to 1.15 format in the destination buffer */ |
| *pDst++ = (q15_t) (__SSAT((sum >> 15), 16)); |
| |
| /* 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; |
| |
| i = (uint32_t) phaseLen - 1u; |
| |
| while(i > 0u) |
| { |
| *pStateCurnt++ = *pState++; |
| |
| /* Decrement the loop counter */ |
| i--; |
| } |
| |
| } |
| |
| #endif /* #ifndef ARM_MATH_CM0_FAMILY */ |
| |
| |
| /** |
| * @} end of FIR_Interpolate group |
| */ |
