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/7_iir_echo.cpp | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
create mode 100644 examples/7_iir_echo.cpp
(limited to 'examples/7_iir_echo.cpp')
diff --git a/examples/7_iir_echo.cpp b/examples/7_iir_echo.cpp
new file mode 100644
index 0000000..57e5605
--- /dev/null
+++ b/examples/7_iir_echo.cpp
@@ -0,0 +1,22 @@
+Sample *process_data(Samples samples)
+{
+ constexpr float alpha = 0.75;
+ constexpr unsigned int D = 100;
+
+ static Sample output[samples.size()];
+ static Sample prev[D]; // prev[0] = output[0 - D]
+
+ // Do calculations with previous output
+ for (unsigned int i = 0; i < D; i++)
+ output[i] = samples[i] + alpha * (prev[i] - 2048);
+
+ // Do calculations with current samples
+ for (unsigned int i = D; i < samples.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)];
+
+ return output;
+}
--
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/7_iir_echo.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";
--
cgit v1.2.3