From 1b176cf6cd75c8031a140961655cdd3c16589a68 Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Sun, 9 Jan 2022 12:28:19 -0500
Subject: small changes; sig gen square(), triangle(), pulse()
---
examples/4_fir_pro.cpp | 478 +++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 478 insertions(+)
create mode 100644 examples/4_fir_pro.cpp
(limited to 'examples/4_fir_pro.cpp')
diff --git a/examples/4_fir_pro.cpp b/examples/4_fir_pro.cpp
new file mode 100644
index 0000000..b1a6832
--- /dev/null
+++ b/examples/4_fir_pro.cpp
@@ -0,0 +1,478 @@
+#include <cstdint>
+using float32_t = float;
+
+typedef struct
+{
+ uint16_t numTaps; /**< number of filter coefficients in the filter. */
+ float32_t *pState; /**< points to the state variable array. The array is of length numTaps+blockSize-1. */
+ float32_t *pCoeffs; /**< points to the coefficient array. The array is of length numTaps. */
+} arm_fir_instance_f32;
+
+static void arm_fir_f32(const arm_fir_instance_f32 * S, float32_t * pSrc, float32_t * pDst, uint32_t blockSize);
+
+Sample *process_data(Samples samples)
+{
+ // 1. Define our array sizes (Be sure to set Run > Set buffer size... to below value!)
+ constexpr unsigned int buffer_size = 500;
+ constexpr unsigned int filter_size = 100;
+
+ // 2. Define our filter and the working arrays
+ static float filter[filter_size] = {
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,
+ .01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f,.01f
+ };
+ static float input[buffer_size];
+ static float output[buffer_size];
+ static float working[buffer_size + filter_size];
+
+ // 3. Scale 0-4095 interger sample values to +/- 1.0 floats
+ for (unsigned int i = 0; i < samples.size(); i++)
+ input[i] = (samples[i] - 2048) / 2048.f;
+
+ // 4. Compute the FIR
+ arm_fir_instance_f32 fir { filter_size, working, filter };
+ arm_fir_f32(&fir, input, output, samples.size());
+
+ // 5. Convert float results back to 0-4095 range for output
+ for (unsigned int i = 0; i < samples.size(); i++)
+ samples[i] = output[i] * 2048.f + 2048;
+
+ return samples.data();
+}
+
+// Below taken from the CMSIS DSP Library (find it on GitHub)
+void arm_fir_f32(
+ const arm_fir_instance_f32 * S,
+ float32_t * pSrc,
+ float32_t * pDst,
+ uint32_t blockSize)
+{
+ float32_t *pState = S->pState; /* State pointer */
+ float32_t *pCoeffs = S->pCoeffs; /* Coefficient pointer */
+ float32_t *pStateCurnt; /* Points to the current sample of the state */
+ float32_t *px, *pb; /* Temporary pointers for state and coefficient buffers */
+ float32_t acc0, acc1, acc2, acc3, acc4, acc5, acc6, acc7; /* Accumulators */
+ float32_t x0, x1, x2, x3, x4, x5, x6, x7, c0; /* Temporary variables to hold state and coefficient values */
+ uint32_t numTaps = S->numTaps; /* Number of filter coefficients in the filter */
+ uint32_t i, tapCnt, blkCnt; /* Loop counters */
+ float32_t p0,p1,p2,p3,p4,p5,p6,p7; /* Temporary product values */
+
+ /* S->pState points to state array which contains previous frame (numTaps - 1) samples */
+ /* pStateCurnt points to the location where the new input data should be written */
+ pStateCurnt = &(S->pState[(numTaps - 1u)]);
+
+ /* Apply loop unrolling and compute 8 output values simultaneously.
+ * The variables acc0 ... acc7 hold output values that are being computed:
+ *
+ * acc0 = b[numTaps-1] * x[n-numTaps-1] + b[numTaps-2] * x[n-numTaps-2] + b[numTaps-3] * x[n-numTaps-3] +...+ b[0] * x[0]
+ * acc1 = b[numTaps-1] * x[n-numTaps] + b[numTaps-2] * x[n-numTaps-1] + b[numTaps-3] * x[n-numTaps-2] +...+ b[0] * x[1]
+ * acc2 = b[numTaps-1] * x[n-numTaps+1] + b[numTaps-2] * x[n-numTaps] + b[numTaps-3] * x[n-numTaps-1] +...+ b[0] * x[2]
+ * acc3 = b[numTaps-1] * x[n-numTaps+2] + b[numTaps-2] * x[n-numTaps+1] + b[numTaps-3] * x[n-numTaps] +...+ b[0] * x[3]
+ */
+ blkCnt = blockSize >> 3;
+
+ /* First part of the processing with loop unrolling. Compute 8 outputs at a time.
+ ** a second loop below computes the remaining 1 to 7 samples. */
+ while(blkCnt > 0u)
+ {
+ /* Copy four new input samples into the state buffer */
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+
+ /* Set all accumulators to zero */
+ acc0 = 0.0f;
+ acc1 = 0.0f;
+ acc2 = 0.0f;
+ acc3 = 0.0f;
+ acc4 = 0.0f;
+ acc5 = 0.0f;
+ acc6 = 0.0f;
+ acc7 = 0.0f;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize coeff pointer */
+ pb = (pCoeffs);
+
+ /* This is separated from the others to avoid
+ * a call to __aeabi_memmove which would be slower
+ */
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+ *pStateCurnt++ = *pSrc++;
+
+ /* Read the first seven samples from the state buffer: x[n-numTaps], x[n-numTaps-1], x[n-numTaps-2] */
+ x0 = *px++;
+ x1 = *px++;
+ x2 = *px++;
+ x3 = *px++;
+ x4 = *px++;
+ x5 = *px++;
+ x6 = *px++;
+
+ /* Loop unrolling. Process 8 taps at a time. */
+ tapCnt = numTaps >> 3u;
+
+ /* Loop over the number of taps. Unroll by a factor of 8.
+ ** Repeat until we've computed numTaps-8 coefficients. */
+ while(tapCnt > 0u)
+ {
+ /* Read the b[numTaps-1] coefficient */
+ c0 = *(pb++);
+
+ /* Read x[n-numTaps-3] sample */
+ x7 = *(px++);
+
+ /* acc0 += b[numTaps-1] * x[n-numTaps] */
+ p0 = x0 * c0;
+
+ /* acc1 += b[numTaps-1] * x[n-numTaps-1] */
+ p1 = x1 * c0;
+
+ /* acc2 += b[numTaps-1] * x[n-numTaps-2] */
+ p2 = x2 * c0;
+
+ /* acc3 += b[numTaps-1] * x[n-numTaps-3] */
+ p3 = x3 * c0;
+
+ /* acc4 += b[numTaps-1] * x[n-numTaps-4] */
+ p4 = x4 * c0;
+
+ /* acc1 += b[numTaps-1] * x[n-numTaps-5] */
+ p5 = x5 * c0;
+
+ /* acc2 += b[numTaps-1] * x[n-numTaps-6] */
+ p6 = x6 * c0;
+
+ /* acc3 += b[numTaps-1] * x[n-numTaps-7] */
+ p7 = x7 * c0;
+
+ /* Read the b[numTaps-2] coefficient */
+ c0 = *(pb++);
+
+ /* Read x[n-numTaps-4] sample */
+ x0 = *(px++);
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+
+
+ /* Perform the multiply-accumulate */
+ p0 = x1 * c0;
+ p1 = x2 * c0;
+ p2 = x3 * c0;
+ p3 = x4 * c0;
+ p4 = x5 * c0;
+ p5 = x6 * c0;
+ p6 = x7 * c0;
+ p7 = x0 * c0;
+
+ /* Read the b[numTaps-3] coefficient */
+ c0 = *(pb++);
+
+ /* Read x[n-numTaps-5] sample */
+ x1 = *(px++);
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+
+ /* Perform the multiply-accumulates */
+ p0 = x2 * c0;
+ p1 = x3 * c0;
+ p2 = x4 * c0;
+ p3 = x5 * c0;
+ p4 = x6 * c0;
+ p5 = x7 * c0;
+ p6 = x0 * c0;
+ p7 = x1 * c0;
+
+ /* Read the b[numTaps-4] coefficient */
+ c0 = *(pb++);
+
+ /* Read x[n-numTaps-6] sample */
+ x2 = *(px++);
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+
+ /* Perform the multiply-accumulates */
+ p0 = x3 * c0;
+ p1 = x4 * c0;
+ p2 = x5 * c0;
+ p3 = x6 * c0;
+ p4 = x7 * c0;
+ p5 = x0 * c0;
+ p6 = x1 * c0;
+ p7 = x2 * c0;
+
+ /* Read the b[numTaps-4] coefficient */
+ c0 = *(pb++);
+
+ /* Read x[n-numTaps-6] sample */
+ x3 = *(px++);
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+
+ /* Perform the multiply-accumulates */
+ p0 = x4 * c0;
+ p1 = x5 * c0;
+ p2 = x6 * c0;
+ p3 = x7 * c0;
+ p4 = x0 * c0;
+ p5 = x1 * c0;
+ p6 = x2 * c0;
+ p7 = x3 * c0;
+
+ /* Read the b[numTaps-4] coefficient */
+ c0 = *(pb++);
+
+ /* Read x[n-numTaps-6] sample */
+ x4 = *(px++);
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+
+ /* Perform the multiply-accumulates */
+ p0 = x5 * c0;
+ p1 = x6 * c0;
+ p2 = x7 * c0;
+ p3 = x0 * c0;
+ p4 = x1 * c0;
+ p5 = x2 * c0;
+ p6 = x3 * c0;
+ p7 = x4 * c0;
+
+ /* Read the b[numTaps-4] coefficient */
+ c0 = *(pb++);
+
+ /* Read x[n-numTaps-6] sample */
+ x5 = *(px++);
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+
+ /* Perform the multiply-accumulates */
+ p0 = x6 * c0;
+ p1 = x7 * c0;
+ p2 = x0 * c0;
+ p3 = x1 * c0;
+ p4 = x2 * c0;
+ p5 = x3 * c0;
+ p6 = x4 * c0;
+ p7 = x5 * c0;
+
+ /* Read the b[numTaps-4] coefficient */
+ c0 = *(pb++);
+
+ /* Read x[n-numTaps-6] sample */
+ x6 = *(px++);
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+
+ /* Perform the multiply-accumulates */
+ p0 = x7 * c0;
+ p1 = x0 * c0;
+ p2 = x1 * c0;
+ p3 = x2 * c0;
+ p4 = x3 * c0;
+ p5 = x4 * c0;
+ p6 = x5 * c0;
+ p7 = x6 * c0;
+
+ tapCnt--;
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+ }
+
+ /* If the filter length is not a multiple of 8, compute the remaining filter taps */
+ tapCnt = numTaps % 0x8u;
+
+ while(tapCnt > 0u)
+ {
+ /* Read coefficients */
+ c0 = *(pb++);
+
+ /* Fetch 1 state variable */
+ x7 = *(px++);
+
+ /* Perform the multiply-accumulates */
+ p0 = x0 * c0;
+ p1 = x1 * c0;
+ p2 = x2 * c0;
+ p3 = x3 * c0;
+ p4 = x4 * c0;
+ p5 = x5 * c0;
+ p6 = x6 * c0;
+ p7 = x7 * c0;
+
+ /* Reuse the present sample states for next sample */
+ x0 = x1;
+ x1 = x2;
+ x2 = x3;
+ x3 = x4;
+ x4 = x5;
+ x5 = x6;
+ x6 = x7;
+
+ acc0 += p0;
+ acc1 += p1;
+ acc2 += p2;
+ acc3 += p3;
+ acc4 += p4;
+ acc5 += p5;
+ acc6 += p6;
+ acc7 += p7;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+
+ /* Advance the state pointer by 8 to process the next group of 8 samples */
+ pState = pState + 8;
+
+ /* The results in the 8 accumulators, store in the destination buffer. */
+ *pDst++ = acc0;
+ *pDst++ = acc1;
+ *pDst++ = acc2;
+ *pDst++ = acc3;
+ *pDst++ = acc4;
+ *pDst++ = acc5;
+ *pDst++ = acc6;
+ *pDst++ = acc7;
+
+ blkCnt--;
+ }
+
+ /* If the blockSize is not a multiple of 8, compute any remaining output samples here.
+ ** No loop unrolling is used. */
+ blkCnt = blockSize % 0x8u;
+
+ while(blkCnt > 0u)
+ {
+ /* Copy one sample at a time into state buffer */
+ *pStateCurnt++ = *pSrc++;
+
+ /* Set the accumulator to zero */
+ acc0 = 0.0f;
+
+ /* Initialize state pointer */
+ px = pState;
+
+ /* Initialize Coefficient pointer */
+ pb = (pCoeffs);
+
+ i = numTaps;
+
+ /* Perform the multiply-accumulates */
+ do
+ {
+ acc0 += *px++ * *pb++;
+ i--;
+
+ } while(i > 0u);
+
+ /* The result is store in the destination buffer. */
+ *pDst++ = acc0;
+
+ /* Advance state pointer by 1 for the next sample */
+ pState = pState + 1;
+
+ blkCnt--;
+ }
+
+ /* Processing is complete.
+ ** Now copy the last numTaps - 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;
+
+ tapCnt = (numTaps - 1u) >> 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 = (numTaps - 1u) % 0x4u;
+
+ /* Copy the remaining q31_t data */
+ while(tapCnt > 0u)
+ {
+ *pStateCurnt++ = *pState++;
+
+ /* Decrement the loop counter */
+ tapCnt--;
+ }
+}
--
cgit v1.2.3
From f211f9628854b417000192c59d6ab22b946119b1 Mon Sep 17 00:00:00 2001
From: Clyne Sullivan <clyne@bitgloo.com>
Date: Sun, 22 May 2022 13:37:49 -0400
Subject: make helper funcs inline; drop std::span for algo
---
examples/1_convolve_simple.cpp | 9 +++---
examples/2_convolve_overlap_save.cpp | 8 ++---
examples/3_fir.cpp | 8 ++---
examples/4_fir_pro.cpp | 10 +++----
examples/5_fir_differentiator.cpp | 8 ++---
examples/6_iir_test.cpp | 18 ++++++++---
examples/7_iir_echo.cpp | 16 +++++++---
source/stmdsp/stmdsp_code.hpp | 58 ++++++++++++++++++------------------
8 files changed, 77 insertions(+), 58 deletions(-)
(limited to 'examples/4_fir_pro.cpp')
diff --git a/examples/1_convolve_simple.cpp b/examples/1_convolve_simple.cpp
index 8de05d3..95877f1 100644
--- a/examples/1_convolve_simple.cpp
+++ b/examples/1_convolve_simple.cpp
@@ -7,10 +7,10 @@
* transient response is not calculated.
*/
-Sample *process_data(Samples samples)
+Sample* process_data(Samples samples)
{
- // Define our output buffer. SIZE is the largest size of the 'samples' buffer.
- static Sample buffer[samples.size()];
+ // Define our output buffer.
+ static Samples buffer;
// Define our filter
constexpr unsigned int filter_size = 3;
@@ -19,7 +19,8 @@ Sample *process_data(Samples samples)
};
// Begin convolving:
- for (int n = 0; n < samples.size() - (filter_size - 1); n++) {
+ // SIZE is the size of the sample buffer.
+ for (int n = 0; n < SIZE - (filter_size - 1); n++) {
buffer[n] = 0;
for (int k = 0; k < filter_size; k++)
buffer[n] += samples[n + k] * filter[k];
diff --git a/examples/2_convolve_overlap_save.cpp b/examples/2_convolve_overlap_save.cpp
index 57c020a..5651f3e 100644
--- a/examples/2_convolve_overlap_save.cpp
+++ b/examples/2_convolve_overlap_save.cpp
@@ -11,9 +11,9 @@
* computation.
*/
-Sample *process_data(Samples samples)
+Sample* process_data(Samples samples)
{
- static Sample buffer[samples.size()];
+ static Samples buffer;
constexpr unsigned int filter_size = 3;
float filter[filter_size] = {
@@ -23,7 +23,7 @@ Sample *process_data(Samples samples)
// Keep a buffer of extra samples for overlap-save
static Sample prev[filter_size];
- for (int n = 0; n < samples.size(); n++) {
+ for (int n = 0; n < SIZE; n++) {
buffer[n] = 0;
for (int k = 0; k < filter_size; k++) {
@@ -40,7 +40,7 @@ Sample *process_data(Samples samples)
// Save samples for the next convolution run
for (int i = 0; i < filter_size; i++)
- prev[i] = samples[samples.size() - filter_size + i];
+ prev[i] = samples[SIZE - filter_size + i];
return buffer;
}
diff --git a/examples/3_fir.cpp b/examples/3_fir.cpp
index 3a68500..b6d8751 100644
--- a/examples/3_fir.cpp
+++ b/examples/3_fir.cpp
@@ -7,9 +7,9 @@
* within the available execution time. Samples are also normalized so that they center around zero.
*/
-Sample *process_data(Samples samples)
+Sample* process_data(Samples samples)
{
- static Sample buffer[samples.size()];
+ static Samples buffer;
// Define the filter:
constexpr unsigned int filter_size = 3;
@@ -21,7 +21,7 @@ Sample *process_data(Samples samples)
// Do an overlap-save convolution
static Sample prev[filter_size];
- for (int n = 0; n < samples.size(); n++) {
+ for (int n = 0; n < SIZE; n++) {
// Using a float variable for accumulation allows for better code optimization
float v = 0;
@@ -40,7 +40,7 @@ Sample *process_data(Samples samples)
// Save samples for next convolution
for (int i = 0; i < filter_size; i++)
- prev[i] = samples[samples.size() - filter_size + i];
+ prev[i] = samples[SIZE - filter_size + i];
return buffer;
}
diff --git a/examples/4_fir_pro.cpp b/examples/4_fir_pro.cpp
index b1a6832..1771cd5 100644
--- a/examples/4_fir_pro.cpp
+++ b/examples/4_fir_pro.cpp
@@ -10,7 +10,7 @@ typedef struct
static void arm_fir_f32(const arm_fir_instance_f32 * S, float32_t * pSrc, float32_t * pDst, uint32_t blockSize);
-Sample *process_data(Samples samples)
+Sample* process_data(Samples samples)
{
// 1. Define our array sizes (Be sure to set Run > Set buffer size... to below value!)
constexpr unsigned int buffer_size = 500;
@@ -34,18 +34,18 @@ Sample *process_data(Samples samples)
static float working[buffer_size + filter_size];
// 3. Scale 0-4095 interger sample values to +/- 1.0 floats
- for (unsigned int i = 0; i < samples.size(); i++)
+ for (unsigned int i = 0; i < SIZE; i++)
input[i] = (samples[i] - 2048) / 2048.f;
// 4. Compute the FIR
arm_fir_instance_f32 fir { filter_size, working, filter };
- arm_fir_f32(&fir, input, output, samples.size());
+ arm_fir_f32(&fir, input, output, SIZE);
// 5. Convert float results back to 0-4095 range for output
- for (unsigned int i = 0; i < samples.size(); i++)
+ for (unsigned int i = 0; i < SIZE; i++)
samples[i] = output[i] * 2048.f + 2048;
- return samples.data();
+ return samples;
}
// Below taken from the CMSIS DSP Library (find it on GitHub)
diff --git a/examples/5_fir_differentiator.cpp b/examples/5_fir_differentiator.cpp
index 72415c6..1500dee 100644
--- a/examples/5_fir_differentiator.cpp
+++ b/examples/5_fir_differentiator.cpp
@@ -7,23 +7,23 @@
* A scaling factor is applied so that the output's form is more clearly visible.
*/
-Sample *process_data(Samples samples)
+Sample* process_data(Samples samples)
{
constexpr int scaling_factor = 4;
- static Sample output[samples.size()];
+ static Samples output;
static Sample prev = 2048;
// Compute the first output value using the saved sample.
output[0] = 2048 + ((samples[0] - prev) * scaling_factor);
- for (unsigned int i = 1; i < samples.size(); i++) {
+ for (unsigned int i = 1; i < SIZE; i++) {
// Take the rate of change and scale it.
// 2048 is added as the output should be centered in the voltage range.
output[i] = 2048 + ((samples[i] - samples[i - 1]) * scaling_factor);
}
// Save the last sample for the next iteration.
- prev = samples[samples.size() - 1];
+ prev = samples[SIZE - 1];
return output;
}
diff --git a/examples/6_iir_test.cpp b/examples/6_iir_test.cpp
index 116a680..e0b266d 100644
--- a/examples/6_iir_test.cpp
+++ b/examples/6_iir_test.cpp
@@ -1,13 +1,23 @@
-Sample *process_data(Samples samples)
+/**
+ * 6_iir_test.cpp
+ * Written by Clyne Sullivan.
+ *
+ * Implements a simple infinite impulse response (IIR) filter using an alpha
+ * parameter.
+ * To build upon this example, try setting `alpha` with a parameter knob:
+ * alpha = param1() / 4095.0
+ */
+
+Sample* process_data(Samples samples)
{
constexpr float alpha = 0.7;
static Sample prev = 2048;
samples[0] = (1 - alpha) * samples[0] + alpha * prev;
- for (unsigned int i = 1; i < samples.size(); i++)
+ for (unsigned int i = 1; i < SIZE; i++)
samples[i] = (1 - alpha) * samples[i] + alpha * samples[i - 1];
- prev = samples[samples.size() - 1];
+ prev = samples[SIZE - 1];
- return samples.data();
+ return samples;
}
diff --git a/examples/7_iir_echo.cpp b/examples/7_iir_echo.cpp
index 57e5605..75bf56e 100644
--- a/examples/7_iir_echo.cpp
+++ b/examples/7_iir_echo.cpp
@@ -1,9 +1,17 @@
-Sample *process_data(Samples samples)
+/**
+ * 7_iir_echo.cpp
+ * Written by Clyne Sullivan.
+ *
+ * This filter produces an echo of the given input. There are two parameters:
+ * alpha controls the feedback gain, and D controls the echo/delay length.
+ */
+
+Sample* process_data(Samples samples)
{
constexpr float alpha = 0.75;
constexpr unsigned int D = 100;
- static Sample output[samples.size()];
+ static Samples output;
static Sample prev[D]; // prev[0] = output[0 - D]
// Do calculations with previous output
@@ -11,12 +19,12 @@ Sample *process_data(Samples samples)
output[i] = samples[i] + alpha * (prev[i] - 2048);
// Do calculations with current samples
- for (unsigned int i = D; i < samples.size(); i++)
+ for (unsigned int i = D; i < SIZE; i++)
output[i] = samples[i] + alpha * (output[i - D] - 2048);
// Save outputs for next computation
for (unsigned int i = 0; i < D; i++)
- prev[i] = output[samples.size() - (D - i)];
+ prev[i] = output[SIZE - (D - i)];
return output;
}
diff --git a/source/stmdsp/stmdsp_code.hpp b/source/stmdsp/stmdsp_code.hpp
index 6850459..7ba0ed2 100644
--- a/source/stmdsp/stmdsp_code.hpp
+++ b/source/stmdsp/stmdsp_code.hpp
@@ -118,67 +118,67 @@ return s;
)cpp";
static std::string file_header_l4 = R"cpp(
#include <cstdint>
-#include <span>
using Sample = uint16_t;
-using Samples = std::span<Sample, $0>;
+using Samples = Sample[$0];
+constexpr unsigned int SIZE = $0;
Sample *process_data(Samples samples);
extern "C" void process_data_entry()
{
Sample *samples;
asm("mov %0, r0" : "=r" (samples));
- process_data(Samples(samples, $0));
+ process_data(samples);
}
-static float PI = 3.14159265358979L;
+static inline float PI = 3.14159265358979L;
__attribute__((naked))
-auto sin(float x) {
-asm("vmov.f32 r1, s0;"
+static inline auto sin(float x) {
+ asm("vmov.f32 r1, s0;"
"eor r0, r0;"
"svc 1;"
"vmov.f32 s0, r1;"
"bx lr");
-return 0;
+ return 0;
}
__attribute__((naked))
-auto cos(float x) {
-asm("vmov.f32 r1, s0;"
+static inline auto cos(float x) {
+ asm("vmov.f32 r1, s0;"
"mov r0, #1;"
"svc 1;"
"vmov.f32 s0, r1;"
"bx lr");
-return 0;
+ return 0;
}
__attribute__((naked))
-auto tan(float x) {
-asm("vmov.f32 r1, s0;"
+static inline auto tan(float x) {
+ asm("vmov.f32 r1, s0;"
"mov r0, #2;"
"svc 1;"
"vmov.f32 s0, r1;"
"bx lr");
-return 0;
+ return 0;
}
__attribute__((naked))
-auto sqrt(float) {
-asm("vsqrt.f32 s0, s0; bx lr");
-return 0;
+static inline auto sqrt(float) {
+ asm("vsqrt.f32 s0, s0; bx lr");
+ return 0;
}
-auto readpot1() {
-Sample s;
-asm("push {r4-r11}; eor r0, r0; svc 3; mov %0, r0; pop {r4-r11}" : "=r"(s));
-return s;
+static inline auto param1() {
+ Sample s;
+ asm("eor r0, r0; svc 3; mov %0, r0" : "=r" (s) :: "r0");
+ return s;
}
-auto readpot2() {
-Sample s;
-asm("push {r4-r11}; mov r0, #1; svc 3; mov %0, r0; pop {r4-r11}" : "=r"(s));
-return s;
+static inline auto param2() {
+ Sample s;
+ asm("mov r0, #1; svc 3; mov %0, r0" : "=r" (s) :: "r0");
+ return s;
}
-//void puts(const char *s) {
-// 's' will already be in r0.
-//asm("push {r4-r6}; svc 4; pop {r4-r6}");
+//static inline void puts(const char *s) {
+// // 's' will already be in r0.
+// asm("push {r4-r6}; svc 4; pop {r4-r6}");
//}
// End stmdspgui header code
@@ -187,9 +187,9 @@ return s;
static std::string file_content =
-R"cpp(Sample *process_data(Samples samples)
+R"cpp(Sample* process_data(Samples samples)
{
- return samples.data();
+ return samples;
}
)cpp";
--
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