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;/**
; *
; * File Name: omxVCM4P2_DecodeVLCZigzag_IntraDCVLC_s.s
; * OpenMAX DL: v1.0.2
; * Revision: 12290
; * Date: Wednesday, April 9, 2008
; *
; * (c) Copyright 2007-2008 ARM Limited. All Rights Reserved.
; *
; *
; *
; * Description:
; * Contains modules for zigzag scanning and VLC decoding
; * for inter block.
; *
; *
; *
; * Function: omxVCM4P2_DecodeVLCZigzag_Inter
; *
; * Description:
; * Performs VLC decoding and inverse zigzag scan for one intra coded block.
; *
; * Remarks:
; *
; * Parameters:
; * [in] ppBitStream pointer to the pointer to the current byte in
; * the bitstream buffer
; * [in] pBitOffset pointer to the bit position in the byte pointed
; * to by *ppBitStream. *pBitOffset is valid within [0-7].
; * [in] shortVideoHeader binary flag indicating presence of short_video_header;
; * escape modes 0-3 are used if shortVideoHeader==0,
; * and escape mode 4 is used when shortVideoHeader==1.
; * [out] ppBitStream *ppBitStream is updated after the block is
; * decoded, so that it points to the current byte
; * in the bit stream buffer
; * [out] pBitOffset *pBitOffset is updated so that it points to the
; * current bit position in the byte pointed by
; * *ppBitStream
; * [out] pDst pointer to the coefficient buffer of current
; * block. Must be 16-byte aligned
; *
; * Return Value:
; * OMX_Sts_BadArgErr - bad arguments
; * -At least one of the following pointers is NULL: ppBitStream, *ppBitStream, pBitOffset, pDst, or
; * -pDst is not 16-byte aligned, or
; * -*pBitOffset exceeds [0,7].
; * OMX_Sts_Err - status error
; * -At least one mark bit is equal to zero
; * -Encountered an illegal stream code that cannot be found in the VLC table
; * -Encountered and illegal code in the VLC FLC table
; * -The number of coefficients is greater than 64
; *
; */
INCLUDE omxtypes_s.h
INCLUDE armCOMM_s.h
INCLUDE armCOMM_BitDec_s.h
M_VARIANTS CortexA8
IF CortexA8
;// Import various tables needed for the function
IMPORT armVCM4P2_IntraVlcL0L1 ;// Contains optimized and packed VLC Tables for both Last =1 and last=0
;// Packed in Run:Level:Last format
IMPORT armVCM4P2_IntraL0L1LMAX ;// Contains LMAX table entries with both Last=0 and Last=1
IMPORT armVCM4P2_IntraL0L1RMAX ;// Contains RMAX table entries with both Last=0 and Last=1
IMPORT armVCM4P2_aClassicalZigzagScan ;// contains CLassical, Horizontal, Vertical Zigzag table entries with double the original values
IMPORT armVCM4P2_aIntraDCLumaChromaIndex ;// Contains Optimized DCLuma and DCChroma Index table Entries
IMPORT armVCM4P2_DecodeVLCZigzag_AC_unsafe
;//Input Arguments
ppBitStream RN 0
pBitOffset RN 1
pDst RN 2
PredDir RN 3
shortVideoHeader RN 3
videoComp RN 5
;//Local Variables
Return RN 0
pDCLumaChromaIndex RN 4
pDCChromaIndex RN 7
pVlcTableL0L1 RN 4
pLMAXTableL0L1 RN 4
pRMAXTableL0L1 RN 4
pZigzagTable RN 4
Count RN 6
DCValueSize RN 6
powOfSize RN 7
temp1 RN 5
;// Scratch Registers
RBitStream RN 8
RBitBuffer RN 9
RBitCount RN 10
T1 RN 11
T2 RN 12
DCVal RN 14
;// Allocate stack memory to store optimized VLC,Zigzag, RMAX, LMAX Table Addresses
M_ALLOC4 ppVlcTableL0L1,4
M_ALLOC4 ppLMAXTableL0L1,4
M_ALLOC4 ppRMAXTableL0L1,4
M_ALLOC4 ppZigzagTable,4
M_ALLOC4 pDCCoeff,4
M_START omxVCM4P2_DecodeVLCZigzag_IntraDCVLC,r12
M_ARG shortVideoHeaderonStack,4 ;// Pointer to argument on stack
M_ARG videoComponstack,4 ;// Pointer to argument on stack
;// Decode DC Coefficient
LDR pDCLumaChromaIndex, =armVCM4P2_aIntraDCLumaChromaIndex ;// Load Optimized VLC Table for Luminance and Chrominance
;// Initializing the Bitstream Macro
M_BD_INIT0 ppBitStream, pBitOffset, RBitStream, RBitBuffer, RBitCount
M_LDR videoComp,videoComponstack
M_BD_INIT1 T1, T2, T2
ADD pDCLumaChromaIndex,pDCLumaChromaIndex,videoComp, LSL #6
M_BD_INIT2 T1, T2, T2
M_BD_VLD DCValueSize,T1,T2,pDCLumaChromaIndex,4,2 ;// VLC Decode using optimized Luminance and Chrominance VLC Table
DecodeDC
CMP DCValueSize,#12
BGT ExitError
CMP DCValueSize,#0
MOVEQ DCVal,#0 ;// If DCValueSize is zero then DC coeff =0
BEQ ACDecode ;// Branch to perform AC Coeff Decoding
M_BD_VREAD16 DCVal,DCValueSize,T1,T2 ;// Get DC Value From Bit stream
MOV powOfSize,#1
LSL powOfSize,DCValueSize ;// powOfSize=pow(2,DCValueSize)
CMP DCVal,powOfSize,LSR #1 ;// Compare DCVal with powOfSize/2
ADDLT DCVal,DCVal,#1
SUBLT DCVal,DCVal,powOfSize ;// If Lessthan powOfSize/2 DCVal=DCVal-powOfSize+1
;// Else DCVal= fetchbits from bit stream
CheckDCValueSize
CMP DCValueSize,#8 ;// If DCValueSize greater than 8 check marker bit
BLE ACDecode
M_BD_READ8 temp1,1,T1
TEQ temp1,#0 ;// If Marker bit is zero Exit with an Error Message
BEQ ExitError
;// Decode AC Coefficient
ACDecode
M_STR DCVal,pDCCoeff ;// Store Decoded DC Coeff on Stack
M_BD_FINI ppBitStream,pBitOffset ;// Terminating the Bit stream Macro
LDR pZigzagTable, =armVCM4P2_aClassicalZigzagScan ;// Load Zigzag talbe address
ADD pZigzagTable, pZigzagTable, PredDir, LSL #6 ;// Modify the Zigzag table adress based on PredDir
M_STR pZigzagTable,ppZigzagTable ;// Store zigzag table on stack
LDR pVlcTableL0L1, =armVCM4P2_IntraVlcL0L1 ;// Load Optimized VLC Table With both Last=0 and Last=1 Entries
M_STR pVlcTableL0L1,ppVlcTableL0L1 ;// Store Optimized VLC Table on stack
LDR pLMAXTableL0L1, =armVCM4P2_IntraL0L1LMAX ;// Load LMAX Table
M_STR pLMAXTableL0L1,ppLMAXTableL0L1 ;// Store LMAX table on stack
LDR pRMAXTableL0L1, =armVCM4P2_IntraL0L1RMAX ;// Load RMAX Table
MOV Count,#1 ;// Set Start =1
M_STR pRMAXTableL0L1,ppRMAXTableL0L1 ;// Store RMAX Table on Stack
M_LDR shortVideoHeader,shortVideoHeaderonStack ;// Load the Input Argument From Stack
BL armVCM4P2_DecodeVLCZigzag_AC_unsafe ;// Call the Unsafe Function
M_LDR DCVal,pDCCoeff ;// Get the Decoded DC Value From Stack
STRH DCVal,[pDst] ;// Store the DC Value
B ExitOK
ExitError
M_BD_FINI ppBitStream,pBitOffset ;// Terminating the Bit Stream Macro in case of an Error
MOV Return,#OMX_Sts_Err ;// Exit with an Error Message
ExitOK
M_END
ENDIF
END
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