#include <exec/types.h>
#include <devices/audio.h>

#define NO  0
#define YES 1

extern struct IOAudio *ioa,*audchan[4],*finish[4];
extern SHORT audiochan[128];
extern SHORT waiting[5];
/************************************************************/
VOID SoundOn(SHORT key,UBYTE *ws)

/*  Start a sound channel   */

{
	UWORD tone;
	UWORD periods[16]={452, 428, 404, 381, 359, 339, 320, 302,
		           285, 269, 254, 240, 226, 214, 202, 190};
	SHORT channo,FreeChan();
	
	switch (key)
	{
		case 0x31: {tone=periods[0]; break;}
		case 0x32: {tone=periods[1]; break;}
		case 0x22: {tone=periods[2]; break;}
		case 0x33: {tone=periods[3]; break;}
		case 0x23: {tone=periods[4]; break;}
		case 0x34: {tone=periods[5]; break;}
		case 0x35: {tone=periods[6]; break;}
		case 0x25: {tone=periods[7]; break;}
		case 0x36: {tone=periods[8]; break;}
		case 0x26: {tone=periods[9]; break;}
		case 0x37: {tone=periods[10]; break;}
		case 0x27: {tone=periods[11]; break;}
		case 0x38: {tone=periods[12]; break;}
		case 0x39: {tone=periods[13]; break;}
		case 0x29: {tone=periods[14]; break;}
		case 0x3A: {tone=periods[15]; break;}
		default: tone=0;
	}
	if (((channo = FreeChan())<4)&(key<64))
	{
		audchan[channo]->ioa_Period=tone;
		if(tone==0) audchan[channo]->ioa_Volume=0;
		else audchan[channo]->ioa_Volume=64;
		audchan[channo]->ioa_Data=(UBYTE *)ws;
		audiochan[key]=channo;
		WaitIO(audchan[channo]);
		BeginIO(audchan[channo]);
	}
}

/************************************************************/
VOID SoundOff(SHORT key)

/*  Stop a sound channel  */

{
	SHORT channo;
	
	channo = audiochan[key];
	audiochan[key]=-1;
	if ((channo>=0)&(key<64))
	{
		BeginIO(finish[channo]);
		WaitIO(finish[channo]);
		waiting[channo]=NO;
	}
}

/************************************************************/
SHORT FreeChan()

/*  Finds the first unused audio channel */
{
	SHORT i;
	
	i=0;
	while ((waiting[i]==YES)&&(i<4)) i++;
	waiting[i]=YES;
	return(i);
}