diff options
Diffstat (limited to 'Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df1_fast_q31.c')
| -rw-r--r-- | Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df1_fast_q31.c | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df1_fast_q31.c b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df1_fast_q31.c new file mode 100644 index 0000000..4c30cda --- /dev/null +++ b/Drivers/CMSIS/DSP/Source/FilteringFunctions/arm_biquad_cascade_df1_fast_q31.c @@ -0,0 +1,296 @@ +/* ----------------------------------------------------------------------
+ * Project: CMSIS DSP Library
+ * Title: arm_biquad_cascade_df1_fast_q31.c
+ * Description: Processing function for the Q31 Fast Biquad cascade DirectFormI(DF1) filter
+ *
+ * $Date: 18. March 2019
+ * $Revision: V1.6.0
+ *
+ * Target Processor: Cortex-M cores
+ * -------------------------------------------------------------------- */
+/*
+ * Copyright (C) 2010-2019 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 BiquadCascadeDF1
+ @{
+ */
+
+/**
+ @brief Processing function for the Q31 Biquad cascade filter (fast variant).
+ @param[in] S points to an instance of the Q31 Biquad cascade 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 samples to process per call
+ @return none
+
+ @par Scaling and Overflow Behavior
+ This function is optimized for speed at the expense of fixed-point precision and overflow protection.
+ The result of each 1.31 x 1.31 multiplication is truncated to 2.30 format.
+ These intermediate results are added to a 2.30 accumulator.
+ Finally, the accumulator is saturated and converted to a 1.31 result.
+ The fast version has the same overflow behavior as the standard version and provides less precision since it discards the low 32 bits of each multiplication result.
+ In order to avoid overflows completely the input signal must be scaled down by two bits and lie in the range [-0.25 +0.25). Use the intialization function
+ arm_biquad_cascade_df1_init_q31() to initialize filter structure.
+ @remark
+ Refer to \ref arm_biquad_cascade_df1_q31() for a slower implementation of this function
+ which uses 64-bit accumulation to provide higher precision. Both the slow and the fast versions use the same instance structure.
+ Use the function \ref arm_biquad_cascade_df1_init_q31() to initialize the filter structure.
+ */
+
+void arm_biquad_cascade_df1_fast_q31(
+ const arm_biquad_casd_df1_inst_q31 * S,
+ const q31_t * pSrc,
+ q31_t * pDst,
+ uint32_t blockSize)
+{
+ const q31_t *pIn = pSrc; /* Source pointer */
+ q31_t *pOut = pDst; /* Destination pointer */
+ q31_t *pState = S->pState; /* pState pointer */
+ const q31_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ q31_t acc = 0; /* Accumulator */
+ q31_t b0, b1, b2, a1, a2; /* Filter coefficients */
+ q31_t Xn1, Xn2, Yn1, Yn2; /* Filter pState variables */
+ q31_t Xn; /* Temporary input */
+ int32_t shift = (int32_t) S->postShift + 1; /* Shift to be applied to the output */
+ uint32_t sample, stage = S->numStages; /* Loop counters */
+
+ do
+ {
+ /* Reading the coefficients */
+ b0 = *pCoeffs++;
+ b1 = *pCoeffs++;
+ b2 = *pCoeffs++;
+ a1 = *pCoeffs++;
+ a2 = *pCoeffs++;
+
+ /* Reading the pState values */
+ Xn1 = pState[0];
+ Xn2 = pState[1];
+ Yn1 = pState[2];
+ Yn2 = pState[3];
+
+#if defined (ARM_MATH_LOOPUNROLL)
+
+ /* Apply loop unrolling and compute 4 output values simultaneously. */
+ /* Variables acc ... acc3 hold output values that are being computed:
+ *
+ * acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2]
+ */
+
+ /* Loop unrolling: Compute 4 outputs at a time */
+ sample = blockSize >> 2U;
+
+ while (sample > 0U)
+ {
+ /* Read the input */
+ Xn = *pIn;
+
+ /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
+ /* acc = b0 * x[n] */
+ /* acc = (q31_t) (((q63_t) b1 * Xn1) >> 32);*/
+ mult_32x32_keep32_R(acc, b1, Xn1);
+ /* acc += b1 * x[n-1] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b0 * (Xn))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b0, Xn);
+ /* acc += b[2] * x[n-2] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b2 * (Xn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b2, Xn2);
+ /* acc += a1 * y[n-1] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a1 * (Yn1))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a1, Yn1);
+ /* acc += a2 * y[n-2] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a2 * (Yn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a2, Yn2);
+
+ /* The result is converted to 1.31 , Yn2 variable is reused */
+ Yn2 = acc << shift;
+
+ /* Read the second input */
+ Xn2 = *(pIn + 1U);
+
+ /* Store the output in the destination buffer. */
+ *pOut = Yn2;
+
+ /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
+ /* acc = b0 * x[n] */
+ /* acc = (q31_t) (((q63_t) b0 * (Xn2)) >> 32);*/
+ mult_32x32_keep32_R(acc, b0, Xn2);
+ /* acc += b1 * x[n-1] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b1 * (Xn))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b1, Xn);
+ /* acc += b[2] * x[n-2] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b2 * (Xn1))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b2, Xn1);
+ /* acc += a1 * y[n-1] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a1 * (Yn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a1, Yn2);
+ /* acc += a2 * y[n-2] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a2 * (Yn1))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a2, Yn1);
+
+ /* The result is converted to 1.31, Yn1 variable is reused */
+ Yn1 = acc << shift;
+
+ /* Read the third input */
+ Xn1 = *(pIn + 2U);
+
+ /* Store the output in the destination buffer. */
+ *(pOut + 1U) = Yn1;
+
+ /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
+ /* acc = b0 * x[n] */
+ /* acc = (q31_t) (((q63_t) b0 * (Xn1)) >> 32);*/
+ mult_32x32_keep32_R(acc, b0, Xn1);
+ /* acc += b1 * x[n-1] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b1 * (Xn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b1, Xn2);
+ /* acc += b[2] * x[n-2] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b2 * (Xn))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b2, Xn);
+ /* acc += a1 * y[n-1] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a1 * (Yn1))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a1, Yn1);
+ /* acc += a2 * y[n-2] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a2 * (Yn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a2, Yn2);
+
+ /* The result is converted to 1.31, Yn2 variable is reused */
+ Yn2 = acc << shift;
+
+ /* Read the forth input */
+ Xn = *(pIn + 3U);
+
+ /* Store the output in the destination buffer. */
+ *(pOut + 2U) = Yn2;
+ pIn += 4U;
+
+ /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
+ /* acc = b0 * x[n] */
+ /* acc = (q31_t) (((q63_t) b0 * (Xn)) >> 32);*/
+ mult_32x32_keep32_R(acc, b0, Xn);
+ /* acc += b1 * x[n-1] */
+ /*acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b1 * (Xn1))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b1, Xn1);
+ /* acc += b[2] * x[n-2] */
+ /*acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b2 * (Xn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b2, Xn2);
+ /* acc += a1 * y[n-1] */
+ /*acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a1 * (Yn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a1, Yn2);
+ /* acc += a2 * y[n-2] */
+ /*acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a2 * (Yn1))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a2, Yn1);
+
+ /* Every time after the output is computed state should be updated. */
+ /* The states should be updated as: */
+ /* Xn2 = Xn1 */
+ Xn2 = Xn1;
+
+ /* The result is converted to 1.31, Yn1 variable is reused */
+ Yn1 = acc << shift;
+
+ /* Xn1 = Xn */
+ Xn1 = Xn;
+
+ /* Store the output in the destination buffer. */
+ *(pOut + 3U) = Yn1;
+ pOut += 4U;
+
+ /* decrement loop counter */
+ sample--;
+ }
+
+ /* Loop unrolling: Compute remaining outputs */
+ sample = (blockSize & 0x3U);
+
+#else
+
+ /* Initialize blkCnt with number of samples */
+ sample = blockSize;
+
+#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
+
+ while (sample > 0U)
+ {
+ /* Read the input */
+ Xn = *pIn++;
+
+ /* acc = b0 * x[n] + b1 * x[n-1] + b2 * x[n-2] + a1 * y[n-1] + a2 * y[n-2] */
+ /* acc = b0 * x[n] */
+ /* acc = (q31_t) (((q63_t) b0 * (Xn)) >> 32);*/
+ mult_32x32_keep32_R(acc, b0, Xn);
+ /* acc += b1 * x[n-1] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b1 * (Xn1))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b1, Xn1);
+ /* acc += b[2] * x[n-2] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) b2 * (Xn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, b2, Xn2);
+ /* acc += a1 * y[n-1] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a1 * (Yn1))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a1, Yn1);
+ /* acc += a2 * y[n-2] */
+ /* acc = (q31_t) ((((q63_t) acc << 32) + ((q63_t) a2 * (Yn2))) >> 32);*/
+ multAcc_32x32_keep32_R(acc, a2, Yn2);
+
+ /* The result is converted to 1.31 */
+ acc = acc << shift;
+
+ /* Every time after the output is computed state should be updated. */
+ /* The states should be updated as: */
+ /* Xn2 = Xn1 */
+ /* Xn1 = Xn */
+ /* Yn2 = Yn1 */
+ /* Yn1 = acc */
+ Xn2 = Xn1;
+ Xn1 = Xn;
+ Yn2 = Yn1;
+ Yn1 = acc;
+
+ /* Store the output in the destination buffer. */
+ *pOut++ = acc;
+
+ /* decrement loop counter */
+ sample--;
+ }
+
+ /* The first stage goes from the input buffer to the output buffer. */
+ /* Subsequent stages occur in-place in the output buffer */
+ pIn = pDst;
+
+ /* Reset to destination pointer */
+ pOut = pDst;
+
+ /* Store the updated state variables back into the pState array */
+ *pState++ = Xn1;
+ *pState++ = Xn2;
+ *pState++ = Yn1;
+ *pState++ = Yn2;
+
+ } while (--stage);
+}
+
+/**
+ @} end of BiquadCascadeDF1 group
+ */
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