bake.s

这是我自己写的关于H.264解码反量化(IQ)部分的ARM汇编程序.请版主给以指教,多谢!

			  AREA           IQ,CODE,READONLY
			  EXPORT         ARM_dequant_ChromaDC2_2
			  IMPORT         udivide
			  IMPORT         dequantcoeff					   			
			  IMPORT         dequant_chroma_data			
			  
num           EQU            4
			  			                			
ARM_dequant_ChromaDC2_2       
              
              STMFD          SP!,{R3-R12,LR}
              LDR            R4,dequantcoeff_addr          
              LDR            R5,dequant_chroma_data_addr           
              MOV            R6,R5
              MOV            R10,#num
              BL             udivide        ; return R0=QP/6 and R1=QP%6
              ADD            R4,R4,R1,LSL #6
              
            /*  SUB            R0,R0,#1       ; qbits=QP/6-1  that is qbits=R0-1       
              CMP            R0,#0          ; compare qbits with0
              BCS            dequanting_1   ; if(qbits>=0) than jump to dequanting_1   qbits>=0 that is QPc>=6
              BCC            dequanting_2   ; if(qbits<0)  than jump to dequanting_2   qbits<0  that is QPc<6 
                                                      
dequanting_1    
              LDR            R7,[R4]
              LDR            R8,[R5],#4
              MUL            R9,R8,R7
              MOV            R9,R9,LSL R0
              STR            R9,[R6],#4
              SUB            R10,R10,#1
              CMP            R10,#0
              BNE            dequanting_1
              LDMFD          SP!,{R3-R12,LR}
              MOV            PC,LR  */
              
dequanting  
              LDR            R7,[R4]
              LDR            R8,[R5],#4
              MUL            R9,R8,R7
              MOV            R9,R9,ASR #1
              STR            R9,[R6],#4
              SUB            R10,R10,#1
              CMP            R10,#0
              BNE            dequanting
              LDMFD          SP!,{R3-R12,LR}
              MOV            PC,LR
              
                                                     
dequantcoeff_addr               
              DCD            dequantcoeff 

              
dequant_chroma_data_addr
              DCD            dequant_chroma_data


              
              END