getrange.asm

基于TMS320F2812的AMR+RS编解码+OFDM调制解调源程序。是stand alone运行版本

***************************************************************************
** Description:     getrange() in pitch_fr.c                              
**                                                                         
** Inputs                                                                  
**                                                                         
**	 AR1:		Word16 T0    
**   AR2:		Word16 delta_low                                               	   
**   AR3:		Word16 delta_range
**                                                                         
** Outputs:                                                                
**                                                                         
**	 AR1:		Word16 t0_min
**   AR2:       Word16 t0_max                                           
**                                                                         
** Return value:
**	
**	 none
**                                                                         
** Attribute:   Cycles: 84        Pm: 14                           
**                      
** Modified Registers:  ACC,XAR1,XAR2,XAR3                          
**                                                                         
** Programmer: Liu Yang
**
** Complete time: 2003 4 1	
*****************************************************************************

		.global		_getrange
		
_getrange:
		
		MOV		AL,@AR2			; AL = delta_low
		SUB		@AR1,AL			; AR1 = t0_min	= T0 - delta_low
		CMP		@AR1,#20		; if t0_min < pit_min
		SB		B1,GEQ
		MOV		AR1,#20			; AR1 = t0_min = pit_min = 20
		
B1:		MOV		AL,@AR1			; AL = t0_min
		ADD		AL,@AR3			; AL = t0_max = t0_min + delta_range
		
		CMP		AL,#143			; if t0_max > pit_max
		SB		B2,LEQ
		MOV		AL,#143			; AL = t0_max = pit_max = 143
		SUBR	@AR3,AL			; AR3 = t0_min = t0_max - delta_range
		MOV		@AR1,AR3		; AR1 = t0_min
		
B2:		MOV		AR2,AL			; AR2 = t0_max
		
		LRETR