Some changes

peripherals/audio.c

@@ -0,0 +1,79 @@
+/*
+// Created by bruno on 16.2.2025.
+*/
+
+#include "audio.h"
+
+int pcm_buffer_empty(PcmVoice *pcm) {
+    return pcm->head == pcm->tail;
+}
+
+int pcm_buffer_full(PcmVoice *pcm) {
+    return ((pcm->tail + 1) % PCM_BUFFER_SIZE) == pcm->head;
+}
+
+void pcm_buffer_push(PcmVoice *pcm, uint16_t sample) {
+    if (!pcm_buffer_full(pcm)) {
+        pcm->buffer[pcm->tail] = sample;
+        pcm->tail = (pcm->tail + 1) % PCM_BUFFER_SIZE;
+    }
+}
+
+uint16_t pcm_buffer_pop(PcmVoice *pcm) {
+    if (!pcm_buffer_empty(pcm)) {
+        uint16_t sample = pcm->buffer[pcm->head];
+        pcm->head = (pcm->head + 1) % PCM_BUFFER_SIZE;
+        return sample;
+    }
+    return 0;
+}
+
+void audio_callback(void *userdata, Uint8 *stream, int len) {
+    AudioData *audio = (AudioData *) userdata;
+    int samples = len / sizeof(float);
+
+    for (int i = 0; i < samples; i++) {
+        float mix = 0.0f;
+        int activeVoices = 0;
+
+        for (int v = 0; v < NUM_SYNTH_VOICES; v++) {
+            SynthVoice *voice = &audio->synthVoices[v];
+            if (voice->volume == 0 || voice->frequency == 0) continue;
+
+            float sample = 0.0f;
+            float t = (float) voice->phase / 255.0f * 2.0f - 1.0f;
+
+            switch (voice->waveform) {
+                default:
+                case WAVE_SINE:
+                    sample = sinf(voice->phase * 2.0f * M_PI / 256.0f);
+                    break;
+                case WAVE_SQUARE:
+                    sample = (t >= 0.0f) ? 1.0f : -1.0f;
+                    break;
+                case WAVE_SAWTOOTH:
+                    sample = t;
+                    break;
+                case WAVE_TRIANGLE:
+                    sample = (t < 0) ? -t : t;
+                    break;
+                case WAVE_NOISE:
+                    sample = ((float) rand() / RAND_MAX) * 2.0f - 1.0f;
+                    break;
+            }
+
+            voice->phase += (uint8_t) ((voice->frequency * 256) / SAMPLE_RATE);
+            mix += sample * (voice->volume / 255.0f);
+            activeVoices++;
+        }
+
+        PcmVoice *pcm = &audio->pcmVoice;
+        if (pcm->volume > 0 && !pcm_buffer_empty(pcm)) {
+            float pcmSample = pcm_buffer_pop(pcm) / 65535.0f;
+            mix += pcmSample * (pcm->volume / 255.0f);
+            activeVoices++;
+        }
+
+        ((float *) stream)[i] = (activeVoices > 0) ? mix / activeVoices : 0.0f;
+    }
+}

peripherals/audio.h

@@ -0,0 +1,55 @@
+/*
+// Created by bruno on 16.2.2025.
+*/
+
+#ifndef RISCB_AUDIO_H
+#define RISCB_AUDIO_H
+
+#include <SDL2/SDL.h>
+#include <math.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#define SAMPLE_RATE 44100
+#define NUM_SYNTH_VOICES 3
+#define PCM_BUFFER_SIZE 4096
+
+typedef enum {
+    WAVE_SINE,
+    WAVE_SQUARE,
+    WAVE_SAWTOOTH,
+    WAVE_TRIANGLE,
+    WAVE_NOISE
+} Waveform;
+
+typedef struct {
+    uint8_t volume;
+    uint16_t frequency;
+    uint8_t phase;
+    Waveform waveform;
+} SynthVoice;
+
+typedef struct {
+    uint8_t volume;
+    uint8_t upsample_factor;
+    uint8_t upsample_count;
+    uint16_t buffer[PCM_BUFFER_SIZE];
+    size_t head, tail;
+} PcmVoice;
+
+typedef struct {
+    SynthVoice synthVoices[NUM_SYNTH_VOICES];
+    PcmVoice pcmVoice;
+} AudioData;
+
+int pcm_buffer_empty(PcmVoice *pcm);
+
+int pcm_buffer_full(PcmVoice *pcm);
+
+void pcm_buffer_push(PcmVoice *pcm, uint16_t sample);
+
+uint16_t pcm_buffer_pop(PcmVoice *pcm);
+
+void audio_callback(void *userdata, Uint8 *stream, int len);
+
+#endif //RISCB_AUDIO_H

peripherals/peripheraldata.c

@@ -0,0 +1,7 @@
+//
+// Created by bruno on 16.2.2025.
+//
+
+#include "peripheraldata.h"
+
+AudioData audioData;

peripherals/peripheraldata.h

@@ -0,0 +1,11 @@
+//
+// Created by bruno on 16.2.2025.
+//
+
+#ifndef RISCB_PERIPHERALDATA_H
+#define RISCB_PERIPHERALDATA_H
+
+#include "audio.h"
+
+extern AudioData audioData;
+#endif //RISCB_PERIPHERALDATA_H