--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/audio/dc/aica.c	Sat Oct 05 16:50:56 2002 +0000
@@ -0,0 +1,267 @@
+/* This file is part of the Dreamcast function library.
+ * Please see libdream.c for further details.
+ *
+ * (c)2000 Dan Potter
+ * modify BERO
+ */
+#include "aica.h"
+
+/* #define dc_snd_base ((volatile unsigned char *)0x00800000) */ /* arm side */
+#define dc_snd_base ((volatile unsigned char *)0xa0700000) /* dc side */
+
+/* Some convienence macros */
+#define	SNDREGADDR(x)	(0xa0700000 + (x))
+#define	CHNREGADDR(ch,x)	SNDREGADDR(0x80*(ch)+(x))
+
+
+#define SNDREG32(x)	(*(volatile unsigned long *)SNDREGADDR(x))
+#define SNDREG8(x)	(*(volatile unsigned char *)SNDREGADDR(x))
+#define CHNREG32(ch, x) (*(volatile unsigned long *)CHNREGADDR(ch,x))
+#define CHNREG8(ch, x)	(*(volatile unsigned long *)CHNREGADDR(ch,x))
+
+#define G2_LOCK(OLD) \
+	do { \
+		if (!irq_inside_int()) \
+			OLD = irq_disable(); \
+		/* suspend any G2 DMA here... */ \
+		while((*(volatile unsigned int *)0xa05f688c) & 0x20) \
+			; \
+	} while(0)
+
+#define G2_UNLOCK(OLD) \
+	do { \
+		/* resume any G2 DMA here... */ \
+		if (!irq_inside_int()) \
+			irq_restore(OLD); \
+	} while(0)
+
+
+void aica_init() {
+	int i, j, old;
+	
+	/* Initialize AICA channels */	
+	G2_LOCK(old);
+	SNDREG32(0x2800) = 0x0000;
+	
+	for (i=0; i<64; i++) {
+		for (j=0; j<0x80; j+=4) {
+			if ((j&31)==0) g2_fifo_wait();
+			CHNREG32(i, j) = 0;
+		}
+		g2_fifo_wait();
+		CHNREG32(i,0) = 0x8000;
+		CHNREG32(i,20) = 0x1f;
+	}
+
+	SNDREG32(0x2800) = 0x000f;
+	g2_fifo_wait();
+	G2_UNLOCK(old);
+}
+
+/* Translates a volume from linear form to logarithmic form (required by
+   the AICA chip */
+/* int logs[] = {
+
+0, 40, 50, 58, 63, 68, 73, 77, 80, 83, 86, 89, 92, 94, 97, 99, 101, 103,
+105, 107, 109, 111, 112, 114, 116, 117, 119, 120, 122, 123, 125, 126, 127,
+129, 130, 131, 133, 134, 135, 136, 137, 139, 140, 141, 142, 143, 144, 145,
+146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 156, 157, 158, 159,
+160, 161, 162, 162, 163, 164, 165, 166, 166, 167, 168, 169, 170, 170, 171,
+172, 172, 173, 174, 175, 175, 176, 177, 177, 178, 179, 180, 180, 181, 182,
+182, 183, 183, 184, 185, 185, 186, 187, 187, 188, 188, 189, 190, 190, 191,
+191, 192, 193, 193, 194, 194, 195, 196, 196, 197, 197, 198, 198, 199, 199,
+200, 201, 201, 202, 202, 203, 203, 204, 204, 205, 205, 206, 206, 207, 207,
+208, 208, 209, 209, 210, 210, 211, 211, 212, 212, 213, 213, 214, 214, 215,
+215, 216, 216, 217, 217, 217, 218, 218, 219, 219, 220, 220, 221, 221, 222,
+222, 222, 223, 223, 224, 224, 225, 225, 225, 226, 226, 227, 227, 228, 228,
+228, 229, 229, 230, 230, 230, 231, 231, 232, 232, 232, 233, 233, 234, 234,
+234, 235, 235, 236, 236, 236, 237, 237, 238, 238, 238, 239, 239, 240, 240,
+240, 241, 241, 241, 242, 242, 243, 243, 243, 244, 244, 244, 245, 245, 245,
+246, 246, 247, 247, 247, 248, 248, 248, 249, 249, 249, 250, 250, 250, 251,
+251, 251, 252, 252, 252, 253, 253, 253, 254, 254, 254, 255
+
+}; */
+
+const static unsigned char logs[] = {
+	0, 15, 22, 27, 31, 35, 39, 42, 45, 47, 50, 52, 55, 57, 59, 61,
+	63, 65, 67, 69, 71, 73, 74, 76, 78, 79, 81, 82, 84, 85, 87, 88,
+	90, 91, 92, 94, 95, 96, 98, 99, 100, 102, 103, 104, 105, 106,
+	108, 109, 110, 111, 112, 113, 114, 116, 117, 118, 119, 120, 121,
+	122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134,
+	135, 136, 137, 138, 138, 139, 140, 141, 142, 143, 144, 145, 146,
+	146, 147, 148, 149, 150, 151, 152, 152, 153, 154, 155, 156, 156,
+	157, 158, 159, 160, 160, 161, 162, 163, 164, 164, 165, 166, 167,
+	167, 168, 169, 170, 170, 171, 172, 173, 173, 174, 175, 176, 176,
+	177, 178, 178, 179, 180, 181, 181, 182, 183, 183, 184, 185, 185,
+	186, 187, 187, 188, 189, 189, 190, 191, 191, 192, 193, 193, 194,
+	195, 195, 196, 197, 197, 198, 199, 199, 200, 200, 201, 202, 202,
+	203, 204, 204, 205, 205, 206, 207, 207, 208, 209, 209, 210, 210,
+	211, 212, 212, 213, 213, 214, 215, 215, 216, 216, 217, 217, 218,
+	219, 219, 220, 220, 221, 221, 222, 223, 223, 224, 224, 225, 225,
+	226, 227, 227, 228, 228, 229, 229, 230, 230, 231, 232, 232, 233,
+	233, 234, 234, 235, 235, 236, 236, 237, 237, 238, 239, 239, 240,
+	240, 241, 241, 242, 242, 243, 243, 244, 244, 245, 245, 246, 246,
+	247, 247, 248, 248, 249, 249, 250, 250, 251, 251, 252, 252, 253, 254, 255
+};
+
+/* For the moment this is going to have to suffice, until we really
+   figure out what these mean. */
+#define AICA_PAN(x) ((x)==0x80?(0):((x)<0x80?(0x1f):(0x0f)))
+#define AICA_VOL(x) (0xff - logs[128 + (((x) & 0xff) / 2)])
+//#define AICA_VOL(x) (0xff - logs[x&255])
+
+static inline unsigned  AICA_FREQ(unsigned freq)	{
+	unsigned long freq_lo, freq_base = 5644800;
+	int freq_hi = 7;
+
+	/* Need to convert frequency to floating point format
+	   (freq_hi is exponent, freq_lo is mantissa)
+	   Formula is ferq = 44100*2^freq_hi*(1+freq_lo/1024) */
+	while (freq < freq_base && freq_hi > -8) {
+		freq_base >>= 1;
+		--freq_hi;
+	}
+	while (freq < freq_base && freq_hi > -8) {
+		freq_base >>= 1;
+		freq_hi--;
+	}
+	freq_lo = (freq<<10) / freq_base;
+	return (freq_hi << 11) | (freq_lo & 1023);
+}
+
+/* Sets up a sound channel completely. This is generally good if you want
+   a quick and dirty way to play notes. If you want a more comprehensive
+   set of routines (more like PC wavetable cards) see below.
+   
+   ch is the channel to play on (0 - 63)
+   smpptr is the pointer to the sound data; if you're running off the
+     SH4, then this ought to be (ptr - 0xa0800000); otherwise it's just
+     ptr. Basically, it's an offset into sound ram.
+   mode is one of the mode constants (16 bit, 8 bit, ADPCM)
+   nsamp is the number of samples to play (not number of bytes!)
+   freq is the sampling rate of the sound
+   vol is the volume, 0 to 0xff (0xff is louder)
+   pan is a panning constant -- 0 is left, 128 is center, 255 is right.
+
+   This routine (and the similar ones) owe a lot to Marcus' sound example -- 
+   I hadn't gotten quite this far into dissecting the individual regs yet. */
+void aica_play(int ch,int mode,unsigned long smpptr,int loopst,int loopend,int freq,int vol,int pan,int loopflag) {
+	int i;
+	int val;
+	int old;
+
+	/* Stop the channel (if it's already playing) */
+	aica_stop(ch);
+	/* doesn't seem to be needed, but it's here just in case */
+/*
+	for (i=0; i<256; i++) {
+		asm("nop");
+		asm("nop");
+		asm("nop");
+		asm("nop");
+	}
+*/
+	G2_LOCK(old);
+	/* Envelope setup. The first of these is the loop point,
+	   e.g., where the sample starts over when it loops. The second
+	   is the loop end. This is the full length of the sample when
+	   you are not looping, or the loop end point when you are (though
+	   storing more than that is a waste of memory if you're not doing
+	   volume enveloping). */
+	CHNREG32(ch, 8) = loopst & 0xffff;
+	CHNREG32(ch, 12) = loopend & 0xffff;
+	
+	/* Write resulting values */
+	CHNREG32(ch, 24) = AICA_FREQ(freq);
+	
+	/* Set volume, pan, and some other things that we don't know what
+	   they do =) */
+	CHNREG32(ch, 36) = AICA_PAN(pan) | (0xf<<8);
+	/* Convert the incoming volume and pan into hardware values */
+	/* Vol starts at zero so we can ramp */
+	vol = AICA_VOL(vol);
+	CHNREG32(ch, 40) = 0x24 | (vol<<8);
+	/* Convert the incoming volume and pan into hardware values */
+	/* Vol starts at zero so we can ramp */
+
+	/* If we supported volume envelopes (which we don't yet) then
+	   this value would set that up. The top 4 bits determine the
+	   envelope speed. f is the fastest, 1 is the slowest, and 0
+	   seems to be an invalid value and does weird things). The
+	   default (below) sets it into normal mode (play and terminate/loop).
+	CHNREG32(ch, 16) = 0xf010;
+	*/
+	CHNREG32(ch, 16) = 0x1f;	/* No volume envelope */
+	
+	
+	/* Set sample format, buffer address, and looping control. If
+	   0x0200 mask is set on reg 0, the sample loops infinitely. If
+	   it's not set, the sample plays once and terminates. We'll
+	   also set the bits to start playback here. */
+	CHNREG32(ch, 4) = smpptr & 0xffff;
+	val = 0xc000 | 0x0000 | (mode<<7) | (smpptr >> 16);
+	if (loopflag) val|=0x200;
+	
+	CHNREG32(ch, 0) = val;
+	
+	G2_UNLOCK(old);
+
+	/* Enable playback */
+	/* CHNREG32(ch, 0) |= 0xc000; */
+	g2_fifo_wait();
+
+#if 0
+	for (i=0xff; i>=vol; i--) {
+		if ((i&7)==0) g2_fifo_wait();
+		CHNREG32(ch, 40) =  0x24 | (i<<8);;
+	}
+
+	g2_fifo_wait();
+#endif
+}
+
+/* Stop the sound on a given channel */
+void aica_stop(int ch) {
+	g2_write_32(CHNREGADDR(ch, 0),(g2_read_32(CHNREGADDR(ch, 0)) & ~0x4000) | 0x8000);
+	g2_fifo_wait();
+}
+
+
+/* The rest of these routines can change the channel in mid-stride so you
+   can do things like vibrato and panning effects. */
+   
+/* Set channel volume */
+void aica_vol(int ch,int vol) {
+//	g2_write_8(CHNREGADDR(ch, 41),AICA_VOL(vol));
+	g2_write_32(CHNREGADDR(ch, 40),(g2_read_32(CHNREGADDR(ch, 40))&0xffff00ff)|(AICA_VOL(vol)<<8) );
+	g2_fifo_wait();
+}
+
+/* Set channel pan */
+void aica_pan(int ch,int pan) {
+//	g2_write_8(CHNREGADDR(ch, 36),AICA_PAN(pan));
+	g2_write_32(CHNREGADDR(ch, 36),(g2_read_32(CHNREGADDR(ch, 36))&0xffffff00)|(AICA_PAN(pan)) );
+	g2_fifo_wait();
+}
+
+/* Set channel frequency */
+void aica_freq(int ch,int freq) {
+	g2_write_32(CHNREGADDR(ch, 24),AICA_FREQ(freq));
+	g2_fifo_wait();
+}
+
+/* Get channel position */
+int aica_get_pos(int ch) {
+#if 1
+	/* Observe channel ch */
+	g2_write_32(SNDREGADDR(0x280c),(g2_read_32(SNDREGADDR(0x280c))&0xffff00ff) | (ch<<8));
+	g2_fifo_wait();
+	/* Update position counters */
+	return g2_read_32(SNDREGADDR(0x2814)) & 0xffff;
+#else
+	/* Observe channel ch */
+	g2_write_8(SNDREGADDR(0x280d),ch);
+	/* Update position counters */
+	return g2_read_32(SNDREGADDR(0x2814)) & 0xffff;
+#endif
+}