From 8aa5155ecfbaaa2e67f82561352a5857bc86d39e Mon Sep 17 00:00:00 2001
From: Bad Diode <bd@badd10de.dev>
Date: Sun, 6 Aug 2023 11:13:22 +0200
Subject: Add missing .c files and wishlist TODOs

---
 src/dsound.c | 61 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 src/dsound.c

(limited to 'src/dsound.c')

diff --git a/src/dsound.c b/src/dsound.c
new file mode 100644
index 0000000..cba8c86
--- /dev/null
+++ b/src/dsound.c
@@ -0,0 +1,61 @@
+static bool audio_sync_click = false;
+#define AUDIO_FREQ           40137
+#define AUDIO_BUF_LEN        672
+#define AUDIO_TIMER          65118
+
+s8 audio_buffer[AUDIO_BUF_LEN * 2];
+static int audio_buf_active = 1;
+
+void
+click_timer(void) {
+    DMA_TRANSFER[1].ctrl = 0;
+    TIMER_CTRL_0 = 0;
+    TIMER_CTRL_1 = 0;
+}
+
+void
+play_click(void) {
+    DMA_TRANSFER[1].ctrl = 0;
+    audio_buf_active = 1;
+    TIMER_CTRL_0 = 0;
+    TIMER_CTRL_1 = 0;
+    TIMER_DATA_1 = 0xFFFF - 1500;
+    TIMER_CTRL_1 = TIMER_CTRL_ENABLE | TIMER_CTRL_CASCADE;
+    irs_set(IRQ_TIMER_1, click_timer);
+    TIMER_DATA_0 = AUDIO_TIMER;
+    TIMER_CTRL_0 = TIMER_CTRL_ENABLE;
+    audio_sync_click = false;
+}
+
+void
+init_dsound(void) {
+    // Initialize audio buffers/channels.
+    int high = 1;
+    for (size_t i = 0; i < AUDIO_BUF_LEN * 2; i++) {
+        audio_buffer[i] = 127 * high;
+        if (i % AUDIO_BUF_LEN == 0) {
+            high *= -1;
+        }
+    }
+
+    // Enable the sound chip.
+    SOUND_STATUS = SOUND_ENABLE;
+}
+
+
+void
+sound_vsync() {
+    if(audio_buf_active == 1) {
+        dma_transfer_copy(SOUND_FIFO_A, audio_buffer, 1, 1,
+                DMA_DST_FIXED
+                | DMA_CHUNK_32
+                | DMA_REFRESH
+                | DMA_REPEAT
+                | DMA_ENABLE);
+        // Start playing and set the backbuffer.
+        audio_buf_active = 0;
+    } else {
+        // Flip front/backbuffer.
+        audio_buf_active = 1;
+    }
+}
-- 
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