lag_wind.asm

来自「基于TMS320F2812的AMR+RS编解码+OFDM调制解调源程序。是sta」· 汇编 代码 · 共 48 行

*****************************************************************************
** Description:     lag_wind()      in lag_wind.c                          **
**                                                                         **
** Inputs :                                                                **
**   AR1---Word16  m                   LPC order                           **
**   *XAR2---Word16 r_h[]			   Autocorrelations  (msb)             **
**   *XAR3---Word16 r_l[]			   Autocorrelations  (lsb)             **
**                                                                         **
** Outputs:                                                                **
**   *XAR2---Word16 r_h[]			   Autocorrelations  (msb)             **
**   *XAR3---Word16 r_l[]			   Autocorrelations  (lsb)             **
** Return value :                                                          **
**                                                                         **
** Attribute    :       Cycles: 1116         Pm:12                         **
**                      Modified Registers: AR1,AR4,XAR2,XAR3.XAR6,XAR7    **
**                                XT,ACC,P                                 **
**                                                                         **
** Programmer   :       ZHOU Bei        (ok! Mar 4th,2003)                 **
*****************************************************************************
	  .global _lag_wind
	  
	  .ref	lag_h
	  .ref	lag_l

	  .ref	_mpy_32
	  
_lag_wind:
        DEC		AR1
        MOVL    XAR7,#lag_h
		MOVL    XAR6,#lag_l	        
	
		ADDB    XAR2,#1				;Start working on 2nd word of r_h[]
		ADDB	XAR3,#1				;Start working on 2nd word of r_l[]
_LOOP_67:
		LCR		_mpy_32				;32 bit multiply r*lag
	  
	    ADDB	XAR7,#1
	    ADDB	XAR6,#1
	    
	    MOV 	*XAR2++,AH			;save MSB to r_h
	    LSR		AL,#1
	    MOV     *XAR3++,AL			;save LSB>>1 to r_l
	    	                    
	BANZ    _LOOP_67,AR1--  		;Loop if AR1!=0,AR1--

	
	LRETR