#include"REG51F.h"
#include"intrins.h"
#include"USEH1.h"
#include"Music.h"

//=========================================================================

unsigned int  code FreTab[12]  = { 262,277,294,311,330,349,369,392,415,440,466,494 }; //原始頻率表
unsigned char code SignTab[7]  = { 0,2,4,5,7,9,11 }; 								  //1~7在頻率表中的位置
unsigned char code LengthTab[7]= { 1,2,4,8,16,32,64 };
unsigned char Sound_Temp_TH0,Sound_Temp_TL0;	//音符定時器初值暫存
unsigned char Sound_Temp_TH1,Sound_Temp_TL1;	//音長定時器初值暫存

//函數定義===================================================================
void InitialSound(void)
{
   BeepIO = 0;
   Sound_Temp_TH1 = (65535-(1/1200)*SYSTEM_OSC)/256;	// 計算TL1應裝入的初值 	(10ms的初裝值)
   Sound_Temp_TL1 = (65535-(1/1200)*SYSTEM_OSC)%256;	// 計算TH1應裝入的初值
   TH1 = Sound_Temp_TH1;
   TL1 = Sound_Temp_TL1;
   TMOD  |= 0x11;
   ET0    = 1;
   ET1	  = 0;
   TR0	  = 0;
   TR1    = 0;
   EA     = 1;
}

void BeepTimer0(void) interrupt 1	//音符發生中斷
{
   BeepIO = !BeepIO;
   TH0    = Sound_Temp_TH0;
   TL0    = Sound_Temp_TL0;
}
//**************************************************************************
void Play(unsigned char *Sound,unsigned char Signature,unsigned Octachord,unsigned int Speed)
{
   unsigned int NewFreTab[12];		//新的頻率表
   unsigned char i,j;
   unsigned int Point,LDiv,LDiv0,LDiv1,LDiv2,LDiv4,CurrentFre,Temp_T,SoundLength;
   unsigned char Tone,Length,SL,SH,SM,SLen,XG,FD;
   for(i=0;i<12;i++) 				// 根據調號及升降八度來生成新的頻率表
   {
      j = i + Signature;
      if(j > 11)
      {
         j = j-12;
         NewFreTab[i] = FreTab[j]*2;
      }
      else
         NewFreTab[i] = FreTab[j];

      if(Octachord == 1)
         NewFreTab[i]>>=2;
      else if(Octachord == 3)
         NewFreTab[i]<<=2;
   }

   SoundLength = 0;
   while(Sound[SoundLength] != 0x00)	//計算歌曲長度
   {
      SoundLength+=2;
   }

   Point  = 0;
   Tone   = Sound[Point];
   Length = Sound[Point+1]; 			// 讀出第一個音符和它時時值

   LDiv0 = 12000/Speed;				// 算出1分音符的長度(幾個10ms)
   LDiv4 = LDiv0/4; 					// 算出4分音符的長度
   LDiv4 = LDiv4-LDiv4*SOUND_SPACE; 	// 普通音最長間隔標準
   TR0	 = 0;
   TR1   = 1;
   while(Point < SoundLength)
   {
      extern bit gf_have;
      extern uchar g_kVal;
      if(gf_have&&(g_kVal==KESC))
         return;
      
      SL=Tone%10; 								//計算出音符
      SM=Tone/10%10; 								//計算出高低音
      SH=Tone/100; 								//計算出是否升半
      CurrentFre = NewFreTab[SignTab[SL-1]+SH]; 	//查出對應音符的頻率
      if(SL!=0)
      {
         if (SM==1) CurrentFre >>= 2; 		//低音
         if (SM==3) CurrentFre <<= 2; 		//高音
         Temp_T = 65536-(50000/CurrentFre)*10/(12000000/SYSTEM_OSC);//計算計數器初值
         Sound_Temp_TH0 = Temp_T/256;
         Sound_Temp_TL0 = Temp_T%256;
         TH0 = Sound_Temp_TH0;
         TL0 = Sound_Temp_TL0 + 12; //加12是對中斷延時的補償
      }
      SLen=LengthTab[Length%10]; 	//算出是幾分音符
      XG=Length/10%10; 			//算出音符類型(0普通1連音2頓音)
      FD=Length/100;
      LDiv=LDiv0/SLen; 			//算出連音音符演奏的長度(多少個10ms)
      if (FD==1)
         LDiv=LDiv+LDiv/2;
      if(XG!=1)
         if(XG==0) 				//算出普通音符的演奏長度
      	    if (SLen<=4)
      	       LDiv1=LDiv-LDiv4;
      	    else
      	       LDiv1=LDiv*SOUND_SPACE;
      	 else
      	    LDiv1=LDiv/2; 		//算出頓音的演奏長度
      else
         LDiv1=LDiv;
      if(SL==0) LDiv1=0;
         LDiv2=LDiv-LDiv1; 		//算出不發音的長度
      if (SL!=0)
      {
         TR0=1;
         for(i=LDiv1;i>0;i--) 	//發規定長度的音
         {
            while(TF1==0);
            TH1 = Sound_Temp_TH1;
            TL1 = Sound_Temp_TL1;
            TF1=0;
         }
      }
      if(LDiv2!=0)
      {
         TR0=0; BeepIO=0;
         for(i=LDiv2;i>0;i--) 	//音符間的間隔
         {
            while(TF1==0);
            TH1 = Sound_Temp_TH1;
            TL1 = Sound_Temp_TL1;
            TF1=0;
         }
      }
      Point+=2;
      Tone=Sound[Point];
      Length=Sound[Point+1];
   }
   BeepIO = 0;
}