Re: [hatari-devel] Falcon left-right sound swapper bug?

[David Savinkoff <dsavnkff@xxxxxxxxx>]

Hi,

This patch adds a ring buffer for the microphone. Apply this patch
(mic.patch) after (fifo.patch). Note that this patch compiles, but is
untested because I don't know how to test the microphone. Please
test it for me.

Thank you for the feedback. I'll improve the patch and add anti-aliasing
over the next few days. I will remove the zeros from the patch and
replace with filtered samples.

David Savinkoff

--- hatari/src/falcon/crossbar.c	2014-04-20 23:06:52.000000000 -0700
+++ hatari/src/falcon/crossbar.c	2014-04-20 23:07:55.000000000 -0700
@@ -261,8 +261,6 @@
 	Uint32 dmaRecord_CurrentFrameStart; /* current DmaPlay Frame end ($ff890f $ff8911 $ff8913) */
 	Uint32 dmaRecord_CurrentFrameCount; /* current DmaRecord Frame start ($ff8903 $ff8905 $ff8907) */
 	Uint32 dmaRecord_CurrentFrameEnd;   /* current DmaRecord Frame end ($ff890f $ff8911 $ff8913) */
-	Uint32 adc2dac_readBufferPosition;  /* read position for direct adc->dac transfer */
-	Sint64 adc2dac_readBufferPosition_float; /* float value of read position for direct adc->dac transfer index */
 	
 	Uint32 save_special_transfer;		/* Used in a special undocumented transfer mode (dsp sent is not in handshake mode and dsp receive is in handshake mode) */
 };
@@ -294,6 +292,7 @@
 static struct dma_s dmaRecord;
 static struct codec_s dac;
 static struct codec_s adc;
+static struct codec_s mic;
 static struct dsp_s dspXmit;
 static struct dsp_s dspReceive;
 
@@ -337,6 +336,13 @@
 	adc.writePosition = 0;
 	adc.FIFO_NbBytes = 0;
 
+	/* Microphone inits */
+	memset(mic.buffer_left, 0, sizeof(mic.buffer_left));
+	memset(mic.buffer_right, 0, sizeof(mic.buffer_right));
+	mic.readPosition = 0;
+	mic.writePosition = 0;
+	mic.FIFO_NbBytes = 0;
+
 	/* DSP inits */
 	dspXmit.wordCount = 0;
 
@@ -366,8 +372,6 @@
 	crossbar.gainSettingRight = 3276;
 	crossbar.attenuationSettingLeft = 65535;
 	crossbar.attenuationSettingRight = 65535;
-	crossbar.adc2dac_readBufferPosition = 0;
-	crossbar.adc2dac_readBufferPosition_float = 0;
 
 	/* Start 25 Mhz and 32 Mhz Clocks */
 	Crossbar_Recalculate_Clocks_Cycles();
@@ -1716,6 +1720,21 @@
 			adc.readPosition = adc.writePosition;
 		}
 	}
+
+	bufferIndex = 0;
+	for (i = 0; i < microBuffer_size; i++) {
+		mic.buffer_left[mic.writePosition] = micro_bufferL[bufferIndex];
+		mic.buffer_right[mic.writePosition] = micro_bufferR[bufferIndex]; 
+
+		bufferIndex++;
+
+		mic.writePosition = (mic.writePosition + 1) % DACBUFFER_SIZE;
+
+		if (++mic.FIFO_NbBytes > DACBUFFER_SIZE) {
+			mic.FIFO_NbBytes = DACBUFFER_SIZE;
+			mic.readPosition = mic.writePosition;
+		}
+	}
 }
 
 /**
@@ -1805,20 +1824,6 @@
 	unsigned n = 0;
 	Sint16 adc_leftData, adc_rightData, dac_LeftData, dac_RightData;
 	
-	if (crossbar.isDacMuted) {
-		/* Output sound = 0 */
-		for (i = 0; i < nSamplesToGenerate; i++) {
-			nBufIdx = (nMixBufIdx + i) % MIXBUFFER_SIZE;
-			MixBuffer[nBufIdx][0] = 0;
-			MixBuffer[nBufIdx][1] = 0;
-		}
-
-		/* Counters are refreshed for when DAC becomes unmuted */
-		dac.readPosition = dac.writePosition;
-		crossbar.adc2dac_readBufferPosition = adc.writePosition;
-		return;
-	}
-
 	for (i = 0; i < nSamplesToGenerate; i++)
 	{
 		nBufIdx = (nMixBufIdx + i) % MIXBUFFER_SIZE;
@@ -1830,23 +1835,30 @@
 			dac.buffer_right[dac.writePosition] = 0;
 		}
 
+		if (--mic.FIFO_NbBytes < 0) {
+			mic.FIFO_NbBytes = 0;
+			mic.writePosition = mic.readPosition;
+			mic.buffer_left[mic.writePosition] = 0;
+			mic.buffer_right[mic.writePosition] = 0;
+		}
+
 		/* ADC mixing (PSG sound or microphone sound for left and right channels) */
 		switch (crossbar.codecAdcInput) {
 			case 0:
 			default: /* Just here to remove compiler's warnings */
 				/* Microphone sound for left and right channels */
-				adc_leftData = adc.buffer_left[crossbar.adc2dac_readBufferPosition];
-				adc_rightData = adc.buffer_right[crossbar.adc2dac_readBufferPosition];
+				adc_leftData = mic.buffer_left[mic.readPosition];
+				adc_rightData = mic.buffer_right[mic.readPosition];
 				break;
 			case 1:
 				/* Microphone sound for left channel, PSG sound for right channel */
-				adc_leftData = adc.buffer_left[crossbar.adc2dac_readBufferPosition];
+				adc_leftData = mic.buffer_left[mic.readPosition];
 				adc_rightData = MixBuffer[nBufIdx][1];
 				break;
 			case 2:
 				/* PSG sound for left channel, microphone sound for right channel */
 				adc_leftData = MixBuffer[nBufIdx][0];
-				adc_rightData = adc.buffer_right[crossbar.adc2dac_readBufferPosition];
+				adc_rightData = mic.buffer_right[mic.readPosition];
 				break;
 			case 3:
 				/* PSG sound for left and right channels */
@@ -1891,10 +1903,12 @@
 		dac.readPosition = (dac.readPosition + n) % DACBUFFER_SIZE;
 		dac.readPosition_float &= 0xffffffff;			/* only keep the fractional part */
 		
-		/* Upgrade adc->dac's buffer read pointer */ 
-		crossbar.adc2dac_readBufferPosition_float += crossbar.frequence_ratio;
-		n = crossbar.adc2dac_readBufferPosition_float >> 32;				/* number of samples to skip */
-		crossbar.adc2dac_readBufferPosition = (crossbar.adc2dac_readBufferPosition + n) % DACBUFFER_SIZE;
-		crossbar.adc2dac_readBufferPosition_float &= 0xffffffff;			/* only keep the fractional part */
+		/* Upgrade microphone buffer read pointer */ 
+		mic.readPosition = ++mic.readPosition % DACBUFFER_SIZE;
+
+		if (crossbar.isDacMuted) {
+			MixBuffer[nBufIdx][0] = 0;
+			MixBuffer[nBufIdx][1] = 0;
+		}
 	}
 }