fircycle_init.asm

the filter program write myself,the effect is not bad ,look and kool

			.def 	FIRFILTC_INIT    ; Init Rouine for Circular buffer
FIRFILTC_INIT:			
			POPD	*+ 						; Store the Return Address in stack        
			SAR		AR1,* 
			LAR		AR2,*+,AR2				; ARP=AR2
;-------------------------------------------; create the software stack
			SBRK	#2						; ARP=AR2, AR2->FIR_MODULE_ptr 
			LAR		AR2,*					; ARP=AR2, AR2->coeff_ptr 
;--------------------------------------------
		    LACL  	*						; ARP=AR2, AR2->coeff_ptr, ACC=coeff_ptr
		    ADRK	#2						; ARP=AR2, AR2->order
		    ADDS	* 						; ARP=AR2, AR2->order, ACC=coeff_ptr+order
		    SBRK	#2						; ARP=AR2, AR2->coeff_ptr
		    SACL	*+,0					; ARP=AR2, AR2->brindex, coeff_ptr=coeff_ptr+order  
;-------------------------------------------coeff_ptr point the H[N]         
	        LACL	#1      				; ACC=1
	        SACL	*						; ARP=AR2, AR2->brindex, brindex=1
bri_loop:   LACC	*,1						; ARP=AR2, AR2->brindex, ACC=brindex*2
			SACL	*+					    ; ARP=AR2, AR2->order, brindex=brindex*2 
			SUB		*-						; ARP=AR2, AR2->brindex, ACC=brindex-order
            BCND	bri_loop,LT 
;-------------------------------------------confire the brindex
            LAR		AR4,*+					; ARP=AR2, AR2->order, AR4=brindex
            ADRK	#1	; ARP=AR2, AR2->dbuffer_ptr for the next instruction
            LAR		AR3,*+,AR4; ARP=AR4, AR4=brindex, AR3=dbuffer_ptr & AR2->input
           	MAR		*-,AR3	; ARP=AR3, AR3=dbuffer_ptr, AR4=brindex-1
;------------------------------------at this teime AR4=brindex-1
;-------------------------------------------------AR3=dbuffer_ptr
	        LACL	#0                      ; ACC=0
cbloop:     SACL	*+,0,AR4				; 
	        BANZ	cbloop,*-,AR3
;-------------------------------------------;Clear the delay buffer(brindex ge )
            MAR		*,AR2					; ARP=AR2, AR2->input 
            SACL	*+						; ARP=AR2, AR2->output, input=0
            SACL	*						; ARP=AR2, AR2->output, output=0
;-------------------------------------------
            SBRK	#4						; ARP=AR2, AR2->brindex
            LACL	*                       ; ARP=AR2, AR2->brindex, ACC=brindex
          	SFR                             ; ARP=AR2, AR2->brindex, ACC=brindex/2
          	SACL	*,0,AR1	          ; ARP=AR2, AR2->dbuffer_ptr, brindex=brindex/2
;------------------------------------------;pop the software stack
            SBRK	#2
            PSHD	*
            RET
;at this time 
;brindex=0040h
;dbuffer_ptr=the first data
;coeff_ptr=the last  coeffH[N]