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author | px4dev <px4@purgatory.org> | 2013-01-06 12:52:05 -0800 |
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committer | px4dev <px4@purgatory.org> | 2013-01-06 12:52:05 -0800 |
commit | 4447282260be0780eb6e36f5e953bf56888a5688 (patch) | |
tree | 3ba1e976d998d433397343b79a0612af52075aef /apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_iir_lattice_f32.c | |
parent | 659543f852d18197f68fafee5db5671567b74f4b (diff) | |
download | px4-firmware-4447282260be0780eb6e36f5e953bf56888a5688.tar.gz px4-firmware-4447282260be0780eb6e36f5e953bf56888a5688.tar.bz2 px4-firmware-4447282260be0780eb6e36f5e953bf56888a5688.zip |
Integrate the interesting parts of the CMSIS 3.01 (r3p1) DSP library
Diffstat (limited to 'apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_iir_lattice_f32.c')
-rw-r--r-- | apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_iir_lattice_f32.c | 440 |
1 files changed, 440 insertions, 0 deletions
diff --git a/apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_iir_lattice_f32.c b/apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_iir_lattice_f32.c new file mode 100644 index 000000000..074605553 --- /dev/null +++ b/apps/mathlib/CMSIS/DSP_Lib/Source/FilteringFunctions/arm_iir_lattice_f32.c @@ -0,0 +1,440 @@ +/* ----------------------------------------------------------------------
+* Copyright (C) 2010 ARM Limited. All rights reserved.
+*
+* $Date: 15. February 2012
+* $Revision: V1.1.0
+*
+* Project: CMSIS DSP Library
+* Title: arm_iir_lattice_f32.c
+*
+* Description: Floating-point IIR Lattice filter processing function.
+*
+* 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 1.0.10 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
+ */
+
+/**
+ * @defgroup IIR_Lattice Infinite Impulse Response (IIR) Lattice Filters
+ *
+ * This set of functions implements lattice filters
+ * for Q15, Q31 and floating-point data types. Lattice filters are used in a
+ * variety of adaptive filter applications. The filter structure has feedforward and
+ * feedback components and the net impulse response is infinite length.
+ * The functions operate on blocks
+ * of input and output data and each call to the function processes
+ * <code>blockSize</code> samples through the filter. <code>pSrc</code> and
+ * <code>pDst</code> point to input and output arrays containing <code>blockSize</code> values.
+
+ * \par Algorithm:
+ * \image html IIRLattice.gif "Infinite Impulse Response Lattice filter"
+ * <pre>
+ * fN(n) = x(n)
+ * fm-1(n) = fm(n) - km * gm-1(n-1) for m = N, N-1, ...1
+ * gm(n) = km * fm-1(n) + gm-1(n-1) for m = N, N-1, ...1
+ * y(n) = vN * gN(n) + vN-1 * gN-1(n) + ...+ v0 * g0(n)
+ * </pre>
+ * \par
+ * <code>pkCoeffs</code> points to array of reflection coefficients of size <code>numStages</code>.
+ * Reflection coefficients are stored in time-reversed order.
+ * \par
+ * <pre>
+ * {kN, kN-1, ....k1}
+ * </pre>
+ * <code>pvCoeffs</code> points to the array of ladder coefficients of size <code>(numStages+1)</code>.
+ * Ladder coefficients are stored in time-reversed order.
+ * \par
+ * <pre>
+ * {vN, vN-1, ...v0}
+ * </pre>
+ * <code>pState</code> points to a state array of size <code>numStages + blockSize</code>.
+ * The state variables shown in the figure above (the g values) are stored in the <code>pState</code> array.
+ * 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 arrays cannot be shared.
+ * 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.
+ *
+ * \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.
+ * Set the values in the state buffer to zeros and then manually initialize the instance structure as follows:
+ * <pre>
+ *arm_iir_lattice_instance_f32 S = {numStages, pState, pkCoeffs, pvCoeffs};
+ *arm_iir_lattice_instance_q31 S = {numStages, pState, pkCoeffs, pvCoeffs};
+ *arm_iir_lattice_instance_q15 S = {numStages, pState, pkCoeffs, pvCoeffs};
+ * </pre>
+ * \par
+ * where <code>numStages</code> is the number of stages in the filter; <code>pState</code> points to the state buffer array;
+ * <code>pkCoeffs</code> points to array of the reflection coefficients; <code>pvCoeffs</code> points to the array of ladder coefficients.
+ * \par Fixed-Point Behavior
+ * Care must be taken when using the fixed-point versions of the IIR lattice 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 IIR_Lattice
+ * @{
+ */
+
+/**
+ * @brief Processing function for the floating-point IIR lattice filter.
+ * @param[in] *S points to an instance of the floating-point IIR lattice 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.
+ * @return none.
+ */
+
+#ifndef ARM_MATH_CM0
+
+ /* Run the below code for Cortex-M4 and Cortex-M3 */
+
+void arm_iir_lattice_f32(
+ const arm_iir_lattice_instance_f32 * S,
+ float32_t * pSrc,
+ float32_t * pDst,
+ uint32_t blockSize)
+{
+ float32_t fnext1, gcurr1, gnext; /* Temporary variables for lattice stages */
+ float32_t acc; /* Accumlator */
+ uint32_t blkCnt, tapCnt; /* temporary variables for counts */
+ float32_t *px1, *px2, *pk, *pv; /* temporary pointers for state and coef */
+ uint32_t numStages = S->numStages; /* number of stages */
+ float32_t *pState; /* State pointer */
+ float32_t *pStateCurnt; /* State current pointer */
+ float32_t k1, k2;
+ float32_t v1, v2, v3, v4;
+ float32_t gcurr2;
+ float32_t fnext2;
+
+ /* initialise loop count */
+ blkCnt = blockSize;
+
+ /* initialise state pointer */
+ pState = &S->pState[0];
+
+ /* Sample processing */
+ while(blkCnt > 0u)
+ {
+ /* Read Sample from input buffer */
+ /* fN(n) = x(n) */
+ fnext2 = *pSrc++;
+
+ /* Initialize Ladder coeff pointer */
+ pv = &S->pvCoeffs[0];
+ /* Initialize Reflection coeff pointer */
+ pk = &S->pkCoeffs[0];
+
+ /* Initialize state read pointer */
+ px1 = pState;
+ /* Initialize state write pointer */
+ px2 = pState;
+
+ /* Set accumulator to zero */
+ acc = 0.0;
+
+ /* Loop unrolling. Process 4 taps at a time. */
+ tapCnt = (numStages) >> 2;
+
+ while(tapCnt > 0u)
+ {
+ /* Read gN-1(n-1) from state buffer */
+ gcurr1 = *px1;
+
+ /* read reflection coefficient kN */
+ k1 = *pk;
+
+ /* fN-1(n) = fN(n) - kN * gN-1(n-1) */
+ fnext1 = fnext2 - (k1 * gcurr1);
+
+ /* read ladder coefficient vN */
+ v1 = *pv;
+
+ /* read next reflection coefficient kN-1 */
+ k2 = *(pk + 1u);
+
+ /* Read gN-2(n-1) from state buffer */
+ gcurr2 = *(px1 + 1u);
+
+ /* read next ladder coefficient vN-1 */
+ v2 = *(pv + 1u);
+
+ /* fN-2(n) = fN-1(n) - kN-1 * gN-2(n-1) */
+ fnext2 = fnext1 - (k2 * gcurr2);
+
+ /* gN(n) = kN * fN-1(n) + gN-1(n-1) */
+ gnext = gcurr1 + (k1 * fnext1);
+
+ /* read reflection coefficient kN-2 */
+ k1 = *(pk + 2u);
+
+ /* write gN(n) into state for next sample processing */
+ *px2++ = gnext;
+
+ /* Read gN-3(n-1) from state buffer */
+ gcurr1 = *(px1 + 2u);
+
+ /* y(n) += gN(n) * vN */
+ acc += (gnext * v1);
+
+ /* fN-3(n) = fN-2(n) - kN-2 * gN-3(n-1) */
+ fnext1 = fnext2 - (k1 * gcurr1);
+
+ /* gN-1(n) = kN-1 * fN-2(n) + gN-2(n-1) */
+ gnext = gcurr2 + (k2 * fnext2);
+
+ /* Read gN-4(n-1) from state buffer */
+ gcurr2 = *(px1 + 3u);
+
+ /* y(n) += gN-1(n) * vN-1 */
+ acc += (gnext * v2);
+
+ /* read reflection coefficient kN-3 */
+ k2 = *(pk + 3u);
+
+ /* write gN-1(n) into state for next sample processing */
+ *px2++ = gnext;
+
+ /* fN-4(n) = fN-3(n) - kN-3 * gN-4(n-1) */
+ fnext2 = fnext1 - (k2 * gcurr2);
+
+ /* gN-2(n) = kN-2 * fN-3(n) + gN-3(n-1) */
+ gnext = gcurr1 + (k1 * fnext1);
+
+ /* read ladder coefficient vN-2 */
+ v3 = *(pv + 2u);
+
+ /* y(n) += gN-2(n) * vN-2 */
+ acc += (gnext * v3);
+
+ /* write gN-2(n) into state for next sample processing */
+ *px2++ = gnext;
+
+ /* update pointer */
+ pk += 4u;
+
+ /* gN-3(n) = kN-3 * fN-4(n) + gN-4(n-1) */
+ gnext = (fnext2 * k2) + gcurr2;
+
+ /* read next ladder coefficient vN-3 */
+ v4 = *(pv + 3u);
+
+ /* y(n) += gN-4(n) * vN-4 */
+ acc += (gnext * v4);
+
+ /* write gN-3(n) into state for next sample processing */
+ *px2++ = gnext;
+
+ /* update pointers */
+ px1 += 4u;
+ pv += 4u;
+
+ tapCnt--;
+
+ }
+
+ /* If the filter length is not a multiple of 4, compute the remaining filter taps */
+ tapCnt = (numStages) % 0x4u;
+
+ while(tapCnt > 0u)
+ {
+ gcurr1 = *px1++;
+ /* Process sample for last taps */
+ fnext1 = fnext2 - ((*pk) * gcurr1);
+ gnext = (fnext1 * (*pk++)) + gcurr1;
+ /* Output samples for last taps */
+ acc += (gnext * (*pv++));
+ *px2++ = gnext;
+ fnext2 = fnext1;
+
+ tapCnt--;
+
+ }
+
+ /* y(n) += g0(n) * v0 */
+ acc += (fnext2 * (*pv));
+
+ *px2++ = fnext2;
+
+ /* write out into pDst */
+ *pDst++ = acc;
+
+ /* Advance the state pointer by 4 to process the next group of 4 samples */
+ pState = pState + 1u;
+
+ blkCnt--;
+
+ }
+
+ /* Processing is complete. Now copy last S->numStages samples to start of the buffer
+ for the preperation of next frame process */
+
+ /* Points to the start of the state buffer */
+ pStateCurnt = &S->pState[0];
+ pState = &S->pState[blockSize];
+
+ tapCnt = numStages >> 2u;
+
+ /* copy data */
+ while(tapCnt > 0u)
+ {
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+
+ }
+
+ /* Calculate remaining number of copies */
+ tapCnt = (numStages) % 0x4u;
+
+ /* Copy the remaining q31_t data */
+ while(tapCnt > 0u)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+}
+
+#else
+
+void arm_iir_lattice_f32(
+ const arm_iir_lattice_instance_f32 * S,
+ float32_t * pSrc,
+ float32_t * pDst,
+ uint32_t blockSize)
+{
+ float32_t fcurr, fnext = 0, gcurr, gnext; /* Temporary variables for lattice stages */
+ float32_t acc; /* Accumlator */
+ uint32_t blkCnt, tapCnt; /* temporary variables for counts */
+ float32_t *px1, *px2, *pk, *pv; /* temporary pointers for state and coef */
+ uint32_t numStages = S->numStages; /* number of stages */
+ float32_t *pState; /* State pointer */
+ float32_t *pStateCurnt; /* State current pointer */
+
+
+ /* Run the below code for Cortex-M0 */
+
+ blkCnt = blockSize;
+
+ pState = &S->pState[0];
+
+ /* Sample processing */
+ while(blkCnt > 0u)
+ {
+ /* Read Sample from input buffer */
+ /* fN(n) = x(n) */
+ fcurr = *pSrc++;
+
+ /* Initialize state read pointer */
+ px1 = pState;
+ /* Initialize state write pointer */
+ px2 = pState;
+ /* Set accumulator to zero */
+ acc = 0.0f;
+ /* Initialize Ladder coeff pointer */
+ pv = &S->pvCoeffs[0];
+ /* Initialize Reflection coeff pointer */
+ pk = &S->pkCoeffs[0];
+
+
+ /* Process sample for numStages */
+ tapCnt = numStages;
+
+ while(tapCnt > 0u)
+ {
+ gcurr = *px1++;
+ /* Process sample for last taps */
+ fnext = fcurr - ((*pk) * gcurr);
+ gnext = (fnext * (*pk++)) + gcurr;
+
+ /* Output samples for last taps */
+ acc += (gnext * (*pv++));
+ *px2++ = gnext;
+ fcurr = fnext;
+
+ /* Decrementing loop counter */
+ tapCnt--;
+
+ }
+
+ /* y(n) += g0(n) * v0 */
+ acc += (fnext * (*pv));
+
+ *px2++ = fnext;
+
+ /* write out into pDst */
+ *pDst++ = acc;
+
+ /* Advance the state pointer by 1 to process the next group of samples */
+ pState = pState + 1u;
+ blkCnt--;
+
+ }
+
+ /* Processing is complete. Now copy last S->numStages samples to start of the buffer
+ for the preperation of next frame process */
+
+ /* Points to the start of the state buffer */
+ pStateCurnt = &S->pState[0];
+ pState = &S->pState[blockSize];
+
+ tapCnt = numStages;
+
+ /* Copy the data */
+ while(tapCnt > 0u)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+}
+
+#endif /* #ifndef ARM_MATH_CM0 */
+
+
+/**
+ * @} end of IIR_Lattice group
+ */
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