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📄 mp3decnew.s

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.include	"mp3_def.h"
.include	"mp3_ext.h"
.include	"mp12_ext.h"
.include	"mp12_def.h"

.extern	DecodingHuffman,DecodingDequantizer,DecodingStereo,DecodingReordering
.extern	DecodingAntialias,DecodingIMDCT,SynthesisPolyphase,InversionFreqLine
.extern FindJointStereoSfb,VolumeControl,MP3Equalizer,DecodingStereoLSF

.extern	InitalizeForL2Decoding,ParsingHeaderL2,SelectTableL2,BitAllocationL2
.extern	ScfsiL2,ScalefactorsL2,DequantizerL2,Separate_channel,FetchDequanData
.extern ComposeStereoL12,MP12Equalizer,VolumeConFreq,MP3SpectrumDisplay,MP3LevelMeter
.extern VolumeFadeIn

.extern	InitalizeForL1Decoding,ParsingHeaderL1,SelectTableL1,BitAllocationL1
.extern	ScalefactorsL1,DequantizerL1,Separate_channelL1,Load_L1table
.extern	huff_xdeq_tbl,sec_tbl2,anc_tbl,ancL2_cod,ancL1_cod
.extern LnkBackup,G_cnt,CodecSharedMP3,


.global	_MP3Decoder
/////////////////////////////////////////////////////////////
	Mp3Decoding_section	
/////////////////////////////////////////////////////////////
_MP3Decoder::
Mp3Decoding::
	push	a14

	jsr		BackupGPRSFR
	jsr		InitalizeForDecoding	
	cmp		eq		,r0		,#0
	jpt		Mp3DecodingReturn	

	ld		a12		,#0x2c0050
%1:	ldw		r2		,@[a12]
	and		r2, 	#0x7000
	cmp		eq, 	r2, #(0x1<<12)
	brt		%b1
		
	cmp		eq,		r2, #(0x2<<12)
	brt		%b1
	
	ld		a12		,#0x2c0000					//CONFIG0
	ldw		r0		,@[a12]
	and		r0,		#0xff
	
	ldb		r1		,@[a10+Index_OutPCMSize]	
	cmp		eq		,r1	,#24
	brt		PCM24
	
	or		r0		,#0x4600
	jmp		PCM24End	

PCM24:
	or		r0		,#0x4000

PCM24End:
	ldw		@[a12+0],r0					//SBF1 mac[23:0]->ext[31:0] & zero extension	
	
	// 0ffset read
	ld		a12		,#0x2c0000					
.ifdef PtrLongSize
	ldw		r0		,@[a10+Index_InputBufferOffset]
	ldw		@[a12+0x52],r0
	ldw		r0		,@[a10+Index_InputBufferOffset+2]
	ldw		@[a12+0x54],r0
.else
	ld		r0		,#0
	ldw		@[a12+0x52],r0	
	ldw		r0		,@[a10+Index_InputBufferOffset]
	ldw		@[a12+0x54],r0	
.endif
	ld		r0		,#0x1000					//SBFCON  SBF0 FILL COMMAND & SBF1 FLUSH COMMAND
	ldw		@[a12+0x4a],r0
	//
//	jsr		DetectVolumeOffset
///////////////////////////////////////////////////////////////////////////////////
//	previous buffer level up & down for Digital Volume
///////////////////////////////////////////////////////////////////////////////////
.if(0)
//	ldb		r0		,@[a10+Index_VolumeIndex]
	ldb		r0		,@[a13+Index_VolumeControl]
	eld		a		,G_PrevVol
	ecld	r1		,a
	
	cmp		eq		,r0		,r1
	brt		NotChangedVolFreqLevel

	ecld	a		,r0
	efz16	a
	eld		G_PrevVol,a
	
//	ld		a12		,#IndexFD_Vol
//	ldw		r5		,@[a12+0]
	eld		a		,IndexFD_Vol
	ecld	r5		,a
//	cmp		ge		,r0		,#18
	cmp		ge		,r0		,r5
	brf		NotChangedVolFreqLevel	
	
	eadd	a		,#tbl_volume						; get the value from 
	eld		rp1		,a	
	eld		x0		,@rp1

	eld		sd0		,#((-1&0fh)<<12)|(1<<8)|((-1&0fh)<<4)|(1<<0)
	eld		sd2		,#((-1&0fh)<<12)|(1<<8)|((-1&0fh)<<4)|(1<<0)
	
	ld		r6		,#1024-1	
	eld		rp0		,#Area_imdctPrevCh0
	eld		rp2		,rp0
	eld		y0		,@rp0+s0
PrevSynthLevel2
	emul	x0y0	,y0		,@rp0+s0
	//eld		p		,#0
	bnzd	r6		,PrevSynthLevel2
	eld		@rp2+d0	,p	

	ld		r6		,#2048-1	
	eld		rp0		,#Area_synthesisBufferCh0
	eld		rp2		,rp0
	eld		y0		,@rp0+s0
PrevSynthLevel3
	emul	x0y0	,y0		,@rp0+s0
	//eld		p		,#0
	bnzd	r6		,PrevSynthLevel3
	eld		@rp2+d0	,p

NotChangedVolFreqLevel	
.endif
///////////////////////////////////////////////////////////////////////////////////
	eld		a		,rpd1.index_Glsf
	ecld	r0		,a
	cmp		eq		,r0		,#0
	brt		FirstGranule
	eld		a		,#1
	eld		rpd1.index_GranuleLoop	,a
FirstGranule
	eld		a		,rpd1.index_GranuleLoop
	ecld	r0		,a
	cmp		eq		,r0		,#0
	brt		Mp3DecodingSecondGranule	

	eld		a		,#1
	eld		rpd1.index_GranuleLoop,	a
	eld		a		,#Area_sideInformation+const_sideInformationSize
	eld		rpd1.index_GptrSideInformation,	a
		
	jsr		Fill_bufferMP3		
		
	jsr		ParsingHeader							;when error, nz
///////////////////////////////////////////////////////////////
	eld		a		,GLayerDiff
	ecld	r1		,a
	cmp		eq		,r1		,#1
	jpt		L2Decoding
	cmp		eq		,r1		,#2
	jpt		L1Decoding	
///////////////////////////////////////////////////////////////
	cmp		eq		,r0		,#0
	jpf		Mp3DecodingFrameError

	jsr		GetSideInformation
 	jsr		FetchMainData	

	eld		a		,G_cnt
	eadd	a		,#1
	eld		G_cnt	,a
	ecld	r0		,a
	cmp		eq		,r0		,#957
	brf		pass_debug
	nop
	nop	
pass_debug

	jmp		Mp3DecodingSecondGranuleSUB
Mp3DecodingSecondGranule
	ldw		r0		,@[a13+Index_FrameLength]
	ecld	b		,r0
	efz8	b												;b<-frame size
	esub	b		,#1
	eneg	b
	esra	b
	ecld	r0		,b
	ldw		r5		,@[a13+Index_InputBufferValidData]
	add		r0		,r5
	ldw		@[a13+Index_InputBufferValidData]	,r0
Mp3DecodingSecondGranuleSUB
	eld		a		,rpd1.index_GmpegChannel
	ecld	r0		,a
	and		r0		,#0xff
	ldb		@[a13+Index_ChannelLoop]	,r0

	eld		a,		#Area_leftChannel	
Mp3DecodingChannelLoop1
	eld		rpd1.index_GptrCurrentDecodingData,	a

	jsr		CopySideInformation
	jsr		RestoreForDecoding	

	eld		a		,rpd1.index_Glsf
	ecld	r0		,a
	cmp		eq		,r0		,#0
	brf		LSF_Scalefactor	
	jsr		GetScalefactor
	bra		LSF_ScalefactorEnd	
LSF_Scalefactor	
	jsr		GetScalefactorLSF
LSF_ScalefactorEnd		
	jsr		DecodingHuffman			
	jsr		StoreForNextDecoding	
	jsr		FindJointStereoSfb			
	jsr		DecodingDequantizer	

	eld		a		,#Area_rightChannel	
	ldb		r6		,@[a13+Index_ChannelLoop]
	dec		r6	
	ldb		@[a13+Index_ChannelLoop]	,r6
	
	cmp		eq		,r6		,#0
	brt		Mp3DecodingChannelLoop1

	jsr		DecodingStereoLSF

	eld		a		,rpd1.index_GmpegChannel
	ecld	r0		,a
	and 	r0		,#0xff
	ldb		@[a13+Index_ChannelLoop]	,r0		
	eld		b		,#const_sideInformationSize	
	efz16	a
	etst	nz		,t
	eslat	b	
	eld		a		,rpd1.index_GptrSideInformation		
	esub	a		,b
	eld		rpd1.index_GptrSideInformation,	a

	eld		a		,#Area_leftChannel	
Mp3DecodingChannelLoop2
	eld		rpd1.index_GptrCurrentDecodingData,	a

	jsr		CopySideInformation		
	jsr		DecodingReordering

///////////////////////////////////////////////////////////////////
// Digital Function On Frequency Domain
///////////////////////////////////////////////////////////////////
//	ldb		r0		,@[a10+Index_OptionalFunctionOnOff]
	ldb		r0		,@[a13+Index_EQ_VolumeFlag]
	and		r0		,#0x08
	cmp		eq		,r0		,#0x08
	brf		MP3DigitalSpectrum_Pass

//	jsr		MP3SpectrumDisplay
MP3DigitalSpectrum_Pass
	
//	ldb		r0		,@[a10+Index_OptionalFunctionOnOff]
	ldb		r0		,@[a13+Index_EQ_VolumeFlag]
	and		r0		,#0x04
	cmp		eq		,r0		,#0x04
	brf		MP3DigitalLevel_Pass

//	jsr		MP3LevelMeter
MP3DigitalLevel_Pass

//	ldb		r0		,@[a10+Index_OptionalFunctionOnOff]
	ldb		r0		,@[a13+Index_EQ_VolumeFlag]
	and		r0		,#0x01
	cmp		eq		,r0		,#0x01
	brf		MP3DigitalVOL_Pass

//	jsr		VolumeConFreq
MP3DigitalVOL_Pass
		
//	ldb		r0		,@[a10+Index_OptionalFunctionOnOff]
	ldb		r0		,@[a13+Index_EQ_VolumeFlag]
	and		r0		,#0x02
	cmp		eq		,r0		,#0x02
	brf		MP3DigitalEQ_Pass

//	jsr		MP3Equalizer
MP3DigitalEQ_Pass
///////////////////////////////////////////////////////////////////
	jsr		DecodingAntialias		
	jsr		DecodingIMDCT	
	jsr		InversionFreqLine	
	jsr		SynthesisPolyphase							;b is returned with a updated	
																											
	eld		a		,#Area_rightChannel
	ldb		r6		,@[a13+Index_ChannelLoop]
	dec		r6	
	ldb		@[a13+Index_ChannelLoop]	,r6
	
	cmp		eq		,r6		,#0
	brt		Mp3DecodingChannelLoop2
	esub	b		,#1024
	eld		rpd1.index_GptrSynPrevious,	b				;update the pointer of 
														;synthesis buffer-1024	
	eld		a		,rpd1.index_GranuleLoop
	eadd	a		,#-1
	efz16	a
	eld		rpd1.index_GranuleLoop,	a
Mp3DecodingFrame
//	ldb		r0		,@[a10+Index_OptionalFunctionOnOff]
	ldb		r0		,@[a13+Index_EQ_VolumeFlag]	
	and		r0		,#0x01
	cmp		eq		,r0		,#0x01
	brf		MP3DigitalTDVOL_Pass
	
//	jsr		VolumeControl
MP3DigitalTDVOL_Pass	

	eld		a		,rpd1.index_Glsf
	ecld	r1		,a
	cmp		eq		,r1		,#0
	brf		LSF_start_reset

	eld		a		,G_cnt
	ecp		a		,#3
//	ecp		a		,#5
	enop
	bra		ec1		,start_reset
	
	jmp		start_resetEnd
start_reset	
	push	a14	
	jsr		PcmBufferReset
	pop		a14
start_resetEnd
	jmp		StartReset_End
LSF_start_reset
	cmp		eq		,r1		,#2
	brt		Mpeg25_start

	eld		a		,G_cnt
	ecp		a		,#5
	enop
	bra		ec1		,start_reset2	

	jmp		start_reset2End
start_reset2	
	push	a14
	jsr		PcmBufferReset		
	pop		a14
start_reset2End
	jmp		StartReset_End
Mpeg25_start
	eld		a		,G_cnt
	ecp		a		,#8
	enop
	bra		ec1		,start_reset3	

	jmp		start_reset3End
start_reset3	
	push	a14	
	jsr		PcmBufferReset		
	pop		a14
start_reset3End

StartReset_End

	jsr		ComposeStereo
//	jsr		VolumeFadeIn	
	jsr		MP3_SaveDecodedAudio

	ldw		r0		,@[a10+Index_pParameterH]
	ld		e12		,r0
	ldw		r0		,@[a10+Index_pParameterL]
	ld		r12		,r0
	ldb		r0		,@[a13+Index_Mode]
	ldb		@[a12+Index_P_ChannelLoop]	,r0				//Channel Information

Mp3DecodingFrameError
.if(0)	
	eld		sd0		,#((-1&0fh)<<12)|(1<<8)|((-1&0fh)<<4)|(1<<0)
	eld		a		,#0
	
	ld		r6		,#1024-1	
	eld		rp0		,#Area_imdctPrevCh0
PrevSynthzero
	bnzd	r6		,PrevSynthzero
	eld		@rp0+d0	,a	

	ld		r6		,#2048-1	
	eld		rp0		,#Area_synthesisBufferCh0
PrevSynthzero1
	bnzd	r6		,PrevSynthzero1
	eld		@rp0+d0	,a	
.endif	
	
Mp3DecodingReturn
	jsr		RestoreGPRSFR

	pop		a14
			
	ret
//////////////////////////////////////////////////////////////////////////////////
;	Layer2 Main
;
//////////////////////////////////////////////////////////////////////////////////
L2Decoding::
	ld		a12		,#0x2c0050
%1:	ldw		r2		,@[a12]
	and		r2, 	#0x7000
	cmp		eq, 	r2, #(0x1<<12)
	brt		%b1
		
	cmp		eq,		r2, #(0x2<<12)
	brt		%b1
	
	ld		a12		,#0x2c0000					//CONFIG0
	ldw		r0		,@[a12]
	and		r0,		#0xff
	
	ldb		r1		,@[a10+Index_OutPCMSize]	
	cmp		eq		,r1	,#24
	brt		PCM24L2
	
	or		r0		,#0x4600
	jmp		PCM24EndL2	

PCM24L2:
	or		r0		,#0x4000

PCM24EndL2:
	ldw		@[a12+0],r0					//SBF1 mac[23:0]->ext[31:0] & zero extension	
		
	// 0ffset read
	ld		a12		,#0x2c0000
.ifdef PtrLongSize
	ldw		r0		,@[a10+Index_InputBufferOffset]
	ldw		@[a12+0x52],r0
	ldw		r0		,@[a10+Index_InputBufferOffset+2]
	ldw		@[a12+0x54],r0
.else
	ld		r0		,#0
	ldw		@[a12+0x52],r0	
	ldw		r0		,@[a10+Index_InputBufferOffset]
	ldw		@[a12+0x54],r0	
.endif
	ld		r0		,#0x1000					//SBFCON  SBF0 FILL COMMAND & SBF1 FLUSH COMMAND
	ldw		@[a12+0x4a],r0
////////////////////////////////////////
	jsr		InitalizeForL2Decoding		

	eld		a		,G_cnt
	eadd	a		,#1
	eld		G_cnt	,a

	eld		a		,rpd1.index_GranuleLoop
	ecld	r1		,a
	cmp		eq		,r1		,#0
	brt		SecondGranuleL2

	jsr		Fill_bufferMP3

	jsr		ParsingHeaderL2							
///////////////////////////////////////////////////////////////
	eld		a		,GLayerDiff
	ecld	r1		,a
	ld		r2		,#0
	cmp		eq		,r1		,#1
	brt		Layer_sel
	ldb		@[a13+Index_FrameStartFlag]	,r2	
	ldb		@[a13+Index_GL2Done]		,r2				// warning
	ldw		r0		,@[a10+Index_pParameterH]
	ld		e12		,r0
	ldw		r0		,@[a10+Index_pParameterL]
	ld		r12		,r0
	ldb		@[a12+Index_P_GL2Done]	,r2
	
	jmp		Mp3DecodingReturn
///////////////////////////////////////////////////////////////
Layer_sel	
	cmp		eq		,r0		,#0
	jpf		Mp3DecodingReturn

	eld		sd0		,#((1&0fh)<<12)|(1<<8)|((2&0fh)<<4)|(1<<0)	
	eld		sd1		,#((1&0fh)<<12)|(1<<8)|((2&0fh)<<4)|(1<<0)	

	jsr		SelectTableL2
 	jsr		BitAllocationL2
	jsr		ScfsiL2
	jsr		ScalefactorsL2	
	jsr		FetchDequanData
	jsr		StoreForNextDecoding	
SecondGranuleL2
	jsr		RestoreForDecoding	

	eld		c		,#0
	eld		rpd0.index_Ggr	,c
	eld		a		,rpd1.index_GranuleLoop
	ecp		a		,#1
	enop
	bra		ec0		,first_Ggr
	eld		c		,#6
	eld		rpd0.index_Ggr	,c	
first_Ggr	
	eld		a		,#0
	eld		rpd0.index_GdequanCnt	,a	
DequanGrLoop
	jsr		DequantizerL2

	eld		a		,rpd0.index_Ggr		
	eadd	a		,#1
	eld		rpd0.index_Ggr			,a
	
	eld		a		,rpd0.index_GdequanCnt
	eadd	a		,#1
	eld		rpd0.index_GdequanCnt	,a
	ecp		a		,#6
	enop
	bra		ec2		,DequanGrLoop	

	jsr		Separate_channel						

	eld		a		,rpd0.index_Gnch
	esub	a		,#1
	ecld	r0		,a
	ldb		@[a13+Index_ChannelLoop]	,r0
	
	jsr		StoreForNextDecoding	
	
	eld		a		,#Area_leftChannel	
L2DecodingChannelLoop2
	eld		rpd1.index_GptrCurrentDecodingData,	a	
	
	jsr		SynthesisPolyphase
	
	eld		a		,#Area_rightChannel
	ldb		r6		,@[a13+Index_ChannelLoop]
	dec		r6	
	ldb		@[a13+Index_ChannelLoop]	,r6
	
	cmp		eq		,r6		,#0
	brt		L2DecodingChannelLoop2
	
	esub	b		,#1024
	eld		rpd1.index_GptrSynPrevious,	b				;update the pointer of 	
	
	eld		a		,rpd1.index_GranuleLoop
	ecld	r0		,a
	cmp		eq		,r0		,#0
	brf		pass_firstGr
///////////////////////////////////////////////////////////////////////////////////
	ldw		r2		,@[a13+Index_FrameLength]				;r0<-frame length 

	ldw		r3		,@[a13+Index_InputBufferValidData]
	sub		r3		,r2
	ldw		@[a13+Index_InputBufferValidData]	,r3

	ldw		r3		,@[a13+Index_InputBufferRPointerL]		;source	
	add		r3		,r2
	
	and		r3		,#FetchMASK
	or		r3		,#StartReadPointer
	

	ldw		@[a13+Index_InputBufferRPointerL]	,r3			;source	
	ld		r3		,#0x20
	ldw		@[a13+Index_InputBufferRPointerH]	,r3			;source
///////////////////////////////////////////////////////////////////////////////////
pass_firstGr
	eadd	a		,#-1
	eabs	a
	eld		rpd1.index_GranuleLoop,	a
	
	jsr		ComposeStereoL12								//2002

	jmp		Mp3DecodingFrame
//////////////////////////////////////////////////////////////////////////////////
;	Layer1 Main
;
//////////////////////////////////////////////////////////////////////////////////
L1Decoding::
	ld		a12		,#0x2c0050
%1:	ldw		r2		,@[a12]
	and		r2, 	#0x7000
	cmp		eq, 	r2, #(0x1<<12)
	brt		%b1
		
	cmp		eq,		r2, #(0x2<<12)
	brt		%b1
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