From b7e8b634595445325d10f8fcddcb7d6cdaa8a922 Mon Sep 17 00:00:00 2001
From: Ian C <ianc@noddybox.co.uk>
Date: Tue, 3 Aug 2021 20:26:23 +0000
Subject: First attempt at sound

---
 source/spec.c | 49 +++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 45 insertions(+), 4 deletions(-)

(limited to 'source/spec.c')

diff --git a/source/spec.c b/source/spec.c
index 6cdc7c6..ef132d4 100644
--- a/source/spec.c
+++ b/source/spec.c
@@ -59,6 +59,7 @@
 #define ED_LOAD		0xf1
 
 #define SCAN_CYCLES     224
+#define FRAME_CYCLES    69888
 
 /* The 3DS screen
 */
@@ -153,6 +154,17 @@ static struct
     	{7,0x10}, {7,0x08}, {7,0x04}, {7,0x02}, {7,0x01} 	/* B - SPACE */
     };
 
+/* Sound
+*/
+#define SAMPLE_BUFF_SZ  (SAMPLE_RATE/60)
+
+#define SAMPLE_CYCLE    (FRAME_CYCLES/SAMPLE_BUFF_SZ)
+
+static u8               *sample[2];
+static int              sound_buffer;
+static u8               sound_level;
+static int              sound_ptr;
+static ndspWaveBuf      wave_buff[2];
 
 /* ---------------------------------------- PRIVATE FUNCTIONS
 */
@@ -160,7 +172,7 @@ static void RomPatch(void)
 {
     static const Z80Byte save[]=
     {
-    	0xed, ED_SAVE,		/* (SAVE)		*/
+        0xed, ED_SAVE,		/* (SAVE)		*/
 	0xc9,                   /* RET		        */
 	0xff			/* End of patch		*/
     };
@@ -263,6 +275,13 @@ static int CheckTimers(Z80 *z80, Z80Val val)
 {
     int ret = TRUE;
 
+    if (DSSPEC_Config[DSSPEC_SOUND] &&
+                Z80GetTimer(z80, Z80_TIMER_1) >= SAMPLE_CYCLE)
+    {
+        Z80SetTimer(z80, Z80_TIMER_1, 0);
+        sample[sound_buffer][sound_ptr++] = sound_level;
+    }
+
     if (val > SCAN_CYCLES)
     {
         int y;
@@ -287,6 +306,15 @@ static int CheckTimers(Z80 *z80, Z80Val val)
 
 	    Z80Interrupt(z80,0xff);
 
+            if (DSSPEC_Config[DSSPEC_SOUND])
+            {
+                ndspChnWaveBufAdd(0, wave_buff + sound_buffer);
+                sound_buffer = !sound_buffer;
+                memset(sample[sound_buffer], 0, SAMPLE_BUFF_SZ);
+                sound_ptr = 0;
+                Z80SetTimer(z80, Z80_TIMER_1, 0);
+            }
+
             ret = FALSE;
 	}
 
@@ -298,8 +326,6 @@ static int CheckTimers(Z80 *z80, Z80Val val)
         {
             DrawScanline(y, scanline);
         }
-
-	/* TODO: Process sound emulation */
     }
 
     return ret;
@@ -361,6 +387,18 @@ void SPECInit(Z80 *z80)
     Z80LodgeCallback(z80,eZ80_EDHook,EDCallback);
     Z80LodgeCallback(z80,eZ80_Instruction,CheckTimers);
 
+    /* Create sound buffers and wave vars
+    */
+    sample[0] = linearAlloc(SAMPLE_BUFF_SZ);
+    sample[1] = linearAlloc(SAMPLE_BUFF_SZ);
+
+    wave_buff[0].data_vaddr = sample[0];
+    wave_buff[0].nsamples = SAMPLE_BUFF_SZ;
+    wave_buff[1].data_vaddr = sample[1];
+    wave_buff[1].nsamples = SAMPLE_BUFF_SZ;
+
+    sound_buffer = 0;
+
     SPECReset(z80);
 }
 
@@ -465,6 +503,7 @@ void SPECWritePort(Z80 *z80, Z80Word port, Z80Byte val)
     {
 	case 0xfe:	/* ULA */
 	    border = val & 0x07;
+            sound_level = val & 0x10 ? 128:0;
 	    break;
 
 	case 0xfb:	/* ZX Printer */
@@ -486,11 +525,13 @@ void SPECReset(Z80 *z80)
     	matrix[f]=0x1f;
 
     Z80Reset(z80);
-    Z80ResetCycles(z80,0);
 
     border = 0;
     scanline = 0;
 
+    sound_buffer = 0;
+    sound_ptr = 0;
+
     /* Set up screen
     */
     c=0;
-- 
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