;-----------------------------------------------------------
;		The following program will decoding MP3 bitstream
;		by S/W Algorithm
;			File Name: antalias.s
;			copyright jj,Park      1999.2.7
;	profile
;		1. 6/7//1999
;			- update all	
;-----------------------------------------------------------
.include	"mp3_def.h"
.include	"mp3_ext.h"

SizeOfEqualizerBand	equ		22

		MP3EqualizerSection
;---------------------------------------------------
;
;void Equalizer()
;{
;	if (windowSwitching && blokType = 0x02)
;	{
;		if (mixedBlock)	{						//mixed block
;			for (i = 0; i < 8;++i) {
;				a = coef[i]; ma0 = coef[i+1];
;				for (j = freqIndex_l[i];j < freqIndex_l[i+1];++j)
;					in[j] *= a; a+=ma0;
;			}
;			for (i = 8,k = freqIndex_l[8]; i < 22;++i) {
;				a = coef[i]; ma0 = coef[i+1];;				
;				freqLine = freqIndex_l[i+1] - freqIndex_l[i];
;				for (j = freqIndex_l[i];j < freqLine;j++,k+=3) {
;					if (j > shortEnd)
;						j = k+1;
;					in[k] *= a; a+=ma0;
;			}			
;		}
;		else{								//pure short
;			for (i = 0,k = freqIndex_l[0]; i < 22;++i) {
;				a = coef[i]; ma0 = coef[i+1];;				
;				freqLine = freqIndex_l[i+1] - freqIndex_l[i];
;				for (j = freqIndex_l[i];j < freqLine;j++,k+=3) {
;					if (j > shortEnd)
;						j = k+1;
;					in[k] *= a; a+=ma0;
;			}
;		}
;	}
;	else {								//long block
;		for (i = 0; i < 22;++i) {
;			a = coef[i]; ma0 = coef[i+1];
;			for (j = freqIndex_l[i];j < freqIndex_l[i+1];++j)
;				in[j] *= a; a+=ma0;
;		}
;	}
;}
;0308,modification start 
;f(x) = y1+x*(y2-y1)/(x2-x1)
;---------------------------------------------------
.if(0)
MP3Equalizer::
	eld		sd0		,#((-1&0fh)<<12)|(2<<8)|((-1&0fh)<<4)|(1<<0)	;s0=1, d0=2
	eld		sd2		,#((-1&0fh)<<12)|(1<<8)|((-1&0fh)<<4)|(2<<0)		
	eld		sd3		,#((-1&0fh)<<12)|(1<<8)|((1&0fh)<<4)|(1<<0)	;s0=1
//	data,sfb band init

	eld		c		,rpd1.index_GLongSfBandIndex				;rp2:sfb band index
	eld		rp2		,c
	erpd	rp2+d0											;rp2<-rp2+1	

	eld		b		,rpd1.index_GptrCurrentDecodingData			;input buffer pointer
	eld		rp0		,b	

//  equalizer mode selection
	ldb		r0		,@[a13+Index_EqualizerModeControl]
	cmp		eq		,r0		,#5
	brt		EQ_UserMode			
	
	ecld	a		,r0
	efz16	a
	eld		x0		,a
	eld		y0		,#SizeOfEqualizerBand
	emul	x0y0
	eld		a		,pl
	eadd	a		,#tbl_EqualizerNormal
	eld		rp3		,a

LongBlock	
	ld		r7		,#21
	eld		b		,@rp2+s1								;b<-bands[i+1],rp2<-rp2-1
	eld		x0		,@rp0+s0		;	
MP3EqualizerBandLoop
	eld		c		,@rp2+s0
	esub	b		,c									;b<-bands[i+1]-bands[i],
														;rp2<-rp2+2
	ecld	r6		,b
	sr		r6
	dec		r6

	eld		a		,@rp3+s0				;b<-y1's coefficient
	eld		ma0		,@rp3+s0				;ma0<-(y2-y1)/(x2-x1)'s coefficient	
MP3EqualizerFreqLoop	
	eld		y0		,a					;
	emul	x0y0	,x0		,@rp0+s1
	eld		b		,prn
	eadd	a		,ma0		,@rp0+d0,b		;a<-y1+x*(y2-y1)/(x2-x1)	
	eld		y0		,a					;
	emul	x0y0	,x0		,@rp0+s1
	eld		b		,prn	
	bnzd	r6		,MP3EqualizerFreqLoop
	eadd	a		,ma0		,@rp0+d0,b		;a<-y1+x*(y2-y1)/(x2-x1)
	bnzd	r7		,MP3EqualizerBandLoop
	eld		b		,@rp2+s1

	ret

// user mode process
EQ_UserMode

	ret
.endif
//////////////////////////////////////////////////////////////////////////////////////
//
//////////////////////////////////////////////////////////////////////////////////////
MP3Equalizer::
	eld		sd0		,#((-1&0fh)<<12)|(2<<8)|((-1&0fh)<<4)|(1<<0)	;s0=1, d0=2
	eld		sd2		,#((-1&0fh)<<12)|(1<<8)|((-1&0fh)<<4)|(2<<0)		
	eld		sd3		,#((-1&0fh)<<12)|(1<<8)|((1&0fh)<<4)|(1<<0)	;s0=1

	eld		rp3		,#tbl_Mp3EQ_Info
	eld		b		,rpd1.index_GptrCurrentDecodingData			;input buffer pointer
	eld		rp0		,b	

//  equalizer mode selection
	eld		rp2		,#tbl_Equalizer
	erpd	rp2+d0											;rp2<-rp2+1	

LongBlock	
//	ld		r7		,#10-1
	ld		r7		,#9-1

	eld		x0		,@rp0+s0		;	
	eld		b		,@rp2+s1								;b<-bands[i+1],rp2<-rp2-1
MP3EqualizerBandLoop
//	eld		y0		,b
	eld		c		,@rp2+s0								;b<-bands[i+1]-bands[i],
	esub	b		,c
																																													
	eld		y1		,b
	eld		x1		,@rp3+s0								;step
	emul	x1y1	
	eld		b		,prn
	eld		ma0		,b										;ma<-(y2-y1)/(x2-x1)'s coefficient		
															
	eld		b		,@rp3+s0								;band num															
	esra	b
	ecld	r6		,b										;r2<-frequency lines
	
	cmp		eq		,r6		,#0
	brt		pass_one_data
	
	dec		r6
pass_one_data	

//	eld		a		,y0										;b<-y1's coefficient	
	eld		a		,c										;b<-y1's coefficient	
MP3EqualizerFreqLoop	
	eld		y0		,a					;
	emul	x0y0	,x0		,@rp0+s1
	eld		b		,prn
	eadd	a		,ma0	,@rp0+d0,b						;a<-y1+x*(y2-y1)/(x2-x1)							;a<-y1+x*(y2-y1)/(x2-x1)	
	eld		y0		,a					;
	emul	x0y0	,x0		,@rp0+s1
	eld		b		,prn
	bnzd	r6		,MP3EqualizerFreqLoop
	eadd	a		,ma0	,@rp0+d0,b						;a<-y1+x*(y2-y1)/(x2-x1)

	bnzd	r7		,MP3EqualizerBandLoop
	eld		b		,@rp2+s1
////////////////////////////////////////////////////////////
// last band
	eld		b		,@rp2+s1
	eld		c		,@rp2+s0								;b<-bands[i+1]-bands[i],
	esub	b		,c
																																													
	eld		y1		,b
	eld		x1		,@rp3+s0								;step
	emul	x1y1	
	eld		b		,prn
	eld		ma0		,b										;ma<-(y2-y1)/(x2-x1)'s coefficient		
															
	eld		b		,@rp3+s0								;band num															
	esra	b
	ecld	r6		,b										;r2<-frequency lines
	sub		r6		,#2
															;b<-y1's coefficient	
	eld		a		,c										;b<-y1's coefficient	
MP3EqualizerFreqLoop2	
	eld		y0		,a					;
	emul	x0y0	,x0		,@rp0+s1
	eld		b		,prn
	eadd	a		,ma0	,@rp0+d0,b						;a<-y1+x*(y2-y1)/(x2-x1)							;a<-y1+x*(y2-y1)/(x2-x1)	
	eld		y0		,a					;
	emul	x0y0	,x0		,@rp0+s1
	eld		b		,prn
	bnzd	r6		,MP3EqualizerFreqLoop2
	eadd	a		,ma0	,@rp0+d0,b


	ret
	
	
	
//////////////////////////////////////////////////////////////////////////////////////
//
//////////////////////////////////////////////////////////////////////////////////////	
MP3SpectrumDisplay::
	eld		sd0		,#((-1&0fh)<<12)|(2<<8)|((-1&0fh)<<4)|(1<<0)
	eld		sd3		,#((-1&0fh)<<12)|(1<<8)|((1&0fh)<<4)|(1<<0)	

	ldw		r0		,@[a10+Index_pSpectrumDisplay]
	ldw		r1		,@[a10+Index_pSpectrumDisplay+2]
// for test
//	ld		r0		,#0x20
//	ld		r1		,#0x6000
////////////////////////
	ld		e12		,r0
	ld		r12		,r1

	eld		rp3		,#tbl_Mp3EQ_Info
	eld		b		,rpd1.index_GptrCurrentDecodingData			
	eld		rp0		,b											

	ld		r7		,#10-1							
TenBand_Loop													
	eld		y0		,@rp3+s0
	
	eld		b		,@rp3+s0								
	ecld	r6		,b										
	
	cmp		eq		,r6		,#0
	brt		pass_one_dataSP
	
	dec		r6
pass_one_dataSP	
	eld		a		,#0
OneBandLoop	
	eld		c		,@rp0+s0
	eabs	c	
	
	bnzd	r6		,OneBandLoop
	eadd	a		,c		

	eld		x0		,a
	emul	x0y0
	eld		a		,p
	eld		b		,pl
	
	ecld	r0		,ah
	ecld	r1		,a
	slb		r0
	srb		r1
	and		r1		,#0x00ff
	add		r0		,r1	
	ldw		@[a12+0],r0

	ecld	r0		,a
	ecld	r1		,bh
	slb		r0
	add		r0		,r1
	ldw		@[a12+2],r0

	bnzd	r7		,TenBand_Loop
	add		a12		,#4

	ret	

//////////////////////////////////////////////////////////////////////////////////////
//
//////////////////////////////////////////////////////////////////////////////////////
MP3LevelMeter::
	eld		sd0		,#((-1&0fh)<<12)|(2<<8)|((-1&0fh)<<4)|(1<<0)

	eld		b		,rpd1.index_GptrCurrentDecodingData			
	eld		rp0		,b											
	eld		y0		,#0x38E3				//1/576

	ld		r6		,#576-1							

	eld		a		,#0
FrameBandLoop	
	eld		c		,@rp0+s0
	eabs	c	
	
	bnzd	r6		,FrameBandLoop
	eadd	a		,c		

	eld		x0		,a
	emul	x0y0
	eld		a		,p
	eld		b		,pl
	
	ecld	r0		,ah
	ecld	r1		,a
	slb		r0
	srb		r1
	and		r1		,#0x00ff
	add		r0		,r1						//H16

	ecld	r2		,a
	ecld	r1		,bh
	slb		r2
	add		r2		,r1						//L16

// for test////////////////////////////////////
//	ld		r3		,#0x20
//	ld		r4		,#0x6100
//	ld		e12		,r3
//	ld		r12		,r4
///////////////////////////////////////////////
	ldb		r1		,@[a13+Index_ChannelLoop]	
	cmp		eq		,r1		,#0
	brt 	RightChannelLevel
		
	ldw		@[a10+Index_LevelMeterValueL]	,r0
	ldw		@[a10+Index_LevelMeterValueL+2]	,r2
//	for test
//	ldw		@[a12+0]	,r0
//	ldw		@[a12+2]	,r2

	bra		LevelEnd
RightChannelLevel	
	ldw		@[a10+Index_LevelMeterValueR]	,r0	
	ldw		@[a10+Index_LevelMeterValueR+2]	,r2		
//	for test
//	ldw		@[a12+4]	,r0
//	ldw		@[a12+6]	,r2
LevelEnd
	
	ret	
	
	end