From c4041799fc3c6e6cdcce6121ea2c121fd504a3b6 Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Tue, 25 May 2021 15:01:42 +0200
Subject: Add sample playing prototype (not on UXN yet)

---
 src/common.h |  10 ++++--
 src/main.c   | 108 +++++++++++++++++++++++++++++++++++++++++++++++++++++++----
 2 files changed, 110 insertions(+), 8 deletions(-)

diff --git a/src/common.h b/src/common.h
index 5766565..048708b 100644
--- a/src/common.h
+++ b/src/common.h
@@ -14,6 +14,7 @@ WITH REGARD TO THIS SOFTWARE.
 
 #include "shorthand.h"
 
+#define CPU_FREQUENCY (2 << 23)
 //
 // Memory sections.
 //
@@ -585,10 +586,11 @@ int bios_div(int num, int denom);
 #define SOUND_ENABLE_NOISE_RIGHT   (1 << 0xF)
 
 typedef enum {
+    SOUND_DSOUND  = (0x0 << 0),
     SOUND_SQUARE1 = (0x1 << 0),
     SOUND_SQUARE2 = (0x1 << 1),
-    SOUND_WAVE =    (0x1 << 2),
-    SOUND_NOISE =   (0x1 << 3),
+    SOUND_WAVE    = (0x1 << 2),
+    SOUND_NOISE   = (0x1 << 3),
 } SoundChannel;
 
 u16
@@ -613,6 +615,10 @@ sound_volume(SoundChannel channels, u8 volume) {
 #define SOUND_DSOUND_TIMER_B  (1 << 0xE)
 #define SOUND_DSOUND_RESET_B  (1 << 0xF)
 
+// Direct sound FIFO queues.
+#define SOUND_FIFO_A ((u16*)(MEM_IO + 0xA0))
+#define SOUND_FIFO_B ((u16*)(MEM_IO + 0xA4))
+
 // Sound status bits.
 #define SOUND_ENABLE (1 << 0x7)
 
diff --git a/src/main.c b/src/main.c
index 7764278..0862ca5 100644
--- a/src/main.c
+++ b/src/main.c
@@ -26,6 +26,7 @@ WITH REGARD TO THIS SOFTWARE.
 //
 // Config parameters.
 //
+
 #ifndef TEXT_LAYER
 #define TEXT_LAYER ppu.fg
 #endif
@@ -298,7 +299,8 @@ handle_input(Uxn *u) {
         }
         if (key_tap(KEY_UP) && cursor_position >= KEYBOARD_ROW_SIZE) {
             update_cursor(cursor_position - KEYBOARD_ROW_SIZE);
-        } else if (key_tap(KEY_DOWN) && cursor_position < LEN(keyboard) - KEYBOARD_ROW_SIZE) {
+        } else if (key_tap(KEY_DOWN)
+                && cursor_position < LEN(keyboard) - KEYBOARD_ROW_SIZE) {
             update_cursor(cursor_position + KEYBOARD_ROW_SIZE);
         }
         if (key_tap(KEY_B)) {
@@ -342,6 +344,75 @@ static Uxn u;
 EWRAM_BSS
 static u8 umem[65536];
 
+#include "kick.c"
+
+typedef struct AudioChannel {
+    u32 *samples;
+    u32 n_samples;
+    u16 sampling_freq;
+    bool loop;
+    // TODO: u16 adsr; // attack, decay, sustain, release
+    // TODO: u8 pitch;  // Bit 8 is the "loop" bit
+    // TODO: u8 volume; // VOL_LEFT | (VOL_RIGHT << 4)
+} AudioChannel;
+
+typedef struct APU {
+    AudioChannel chan_0;
+    // u32 *samples_1;
+    // u32 *samples_2;
+    // u32 *samples_3;
+} APU;
+
+
+static APU apu = {0};
+
+void
+reset_sound(AudioChannel *chan) {
+    TIMER_CTRL_0 = 0;
+    TIMER_CTRL_1 = 0;
+    DMA_CTRL(1) = 0;
+
+    // Set max volume, left-right sound, fifo reset and use timer 0 for
+    // DirectSound A.
+    SOUND_DSOUND_MASTER = SOUND_DSOUND_RATIO_A
+        | SOUND_DSOUND_LEFT_A
+        | SOUND_DSOUND_RIGHT_A
+        | SOUND_DSOUND_RESET_A;
+
+    // Prepare DMA copy.
+    dma_transfer_copy(SOUND_FIFO_A, chan->samples, 1, 1,
+            DMA_CHUNK_32 | DMA_REFRESH | DMA_REPEAT | DMA_ENABLE);
+
+    // Timer 1 used to stop playing samples.
+    u32 sample_duration = chan->n_samples;
+    TIMER_DATA_1 = 0xFFFF - sample_duration;
+    TIMER_CTRL_1 = TIMER_CTRL_IRQ
+        | TIMER_CTRL_ENABLE
+        | TIMER_CTRL_CASCADE;
+
+    // Timer 0 used to stop sample playing.
+    TIMER_DATA_0 = 0xFFFF - CPU_FREQUENCY / chan->sampling_freq;
+    TIMER_CTRL_0 = TIMER_CTRL_ENABLE;
+}
+
+void
+irs_stop_sample(void) {
+    if (apu.chan_0.loop) {
+        reset_sound(&apu.chan_0);
+    } else {
+        TIMER_CTRL_0 = 0;
+        DMA_CTRL(1) = 0;
+    }
+}
+
+void
+init_sound(AudioChannel *chan) {
+    chan->samples = voiceraw;
+    chan->n_samples = LEN(voiceraw);
+    chan->sampling_freq = 44100;
+    chan->loop = true;
+}
+
 int main(void) {
     // Initialize filesystem.
     fs_init();
@@ -349,6 +420,7 @@ int main(void) {
     // Register interrupts.
     irq_init();
     irs_set(IRQ_VBLANK, irs_stub);
+    irs_set(IRQ_TIMER_1, irs_stop_sample);
 
     // Initialize VM.
     memset(&u, 0, sizeof(u));
@@ -359,15 +431,39 @@ int main(void) {
     txt_init(1, TEXT_LAYER);
     txt_position(0,0);
 
+    txt_printf("VOICE LOADED: %lu\n", LEN(voiceraw));
+
+    // Enable sound.
+    SOUND_STATUS = SOUND_ENABLE;
+
+    init_sound(&apu.chan_0);
+    reset_sound(&apu.chan_0);
+
     // Main loop.
-    int frame_counter = 0;
-    evaluxn(&u, 0x0100);
+    // int frame_counter = 0;
+    // evaluxn(&u, 0x0100);
+    // u32 flip_cycles = 0;
     while(true) {
         bios_vblank_wait();
-        handle_input(&u);
-        evaluxn(&u, mempeek16(devscreen->dat, 0));
+        // profile_start();
+        // handle_input(&u);
+        // u32 input_cycles = profile_stop();
+        // profile_start();
+        // evaluxn(&u, mempeek16(devscreen->dat, 0));
+        // u32 eval_cycles = profile_stop();
+        // txt_position(0, 8);
+        // txt_printf("INPUT: %lu  \n", input_cycles);
+        // txt_printf("EVAL:  %lu  \n", eval_cycles);
+        // txt_printf("FLIP:  %lu  \n", flip_cycles);
+        // profile_start();
         flipbuf(&ppu);
-        frame_counter++;
+        // flip_cycles = profile_stop();
+        // frame_counter++;
+        poll_keys();
+        if (key_tap(KEY_B)) {
+            txt_printf("TAP B\n");
+            reset_sound(&apu.chan_0);
+        }
     }
 
     return 0;
-- 
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