encode.asm

来自「5509的代码程序」· 汇编 代码 · 共 58 行

;Function:Encode
;		.def Encode
		.text
		.def Encode
		.ref Bw0_data,Encoded_data
Encode:
	amov	#Bw0_data+25,xar0
	amov	#Encoded_data,xar1
	mov		#0,ac0			;ac0用于存放编码器目前的状态
	mov		#5,t1
	mov		#5,brc0
	rptb	IniAc0-1
	mov		*ar0-,ac1
	sfts	ac1,t1
	or		ac1,ac0
	sub		#1,t1	
IniAc0:
;	mov		#Bw0_data,ar0
	amov	#Bw0_data,xar0
	;mov		#0,ac0
	mov		#(26-1),brc0
	rptb	Loop1-1
	mov		*ar0+,ac1
	
	mov		ac1,ac2
	sfts	ac2,#6			;data(i)
	xor		ac0<<#2,ac2		;mod(data(i)+g(2),2)
	xor		ac0<<#3,ac2		;mod(data(i)+g(2)+g(3),2)
	xor		ac0<<#5,ac2		;mod(data(i)+g(2)+g(3)+g(5),2)
	xor		ac0<<#6,ac2		;mod(data(i)+g(2)+g(3)+g(5)+g(6),2)
	sfts	ac2,#-6
	and		#0001,ac2
	mov		ac2,*ar1+		;get g0
	
	mov		ac1,ac2
	sfts	ac2,#6
	xor		ac0<<#1,ac2
	xor		ac0<<#2,ac2
	xor		ac0<<#3,ac2
	xor		ac0<<#6,ac2
	sfts	ac2,#-6
	and		#0001,ac2
	mov		ac2,*ar1+		;get g1
	
	sfts	ac0,#-1			;把g(6)移出去
	
	sfts	ac1,#5
	or		ac1,ac0
Loop1:
	ret