;// ;// Copyright (C) 2007-2008 ARM Limited ;// ;// Licensed under the Apache License, Version 2.0 (the "License"); ;// you may not use this file except in compliance with the License. ;// You may obtain a copy of the License at ;// ;// http://www.apache.org/licenses/LICENSE-2.0 ;// ;// Unless required by applicable law or agreed to in writing, software ;// distributed under the License is distributed on an "AS IS" BASIS, ;// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. ;// See the License for the specific language governing permissions and ;// limitations under the License. ;// ;/** ; * ; * File Name: omxVCM4P2_DecodeVLCZigzag_IntraDCVLC_s.s ; * OpenMAX DL: v1.0.2 ; * Revision: 9641 ; * Date: Thursday, February 7, 2008 ; * ; * ; * ; * ; * 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 ARM1136JS IF ARM1136JS :LOR: 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