PIC單片機的BIN碼轉BCD碼

;
;********************************************************************
;????????????????? Binary To BCD Conversion Routine
;????? This routine converts a 16 Bit binary Number to a 5 Digit
; BCD Number. This routine is useful since PIC16C55 & PIC16C57
; have? two 8 bit ports and one 4 bit port ( total of 5 BCD digits)
;
;?????? The 16 bit binary number is input in locations H_byte and
; L_byte with the high byte in H_byte.
;?????? The 5 digit BCD number is returned in R0, R1 and R2 with R0
; containing the MSD in its right most nibble.
;
;?? Performance :
;?????????????? Program Memory? :?????? 35
;?????????????? Clock Cycles??? :?????? 885
;
;*******************************************************************;
;
count? equ????? 16
temp?? equ????? 17
;
H_byte? equ???? 10
L_byte? equ???? 11
R0????? equ???? 12????????????? ; RAM Assignments
R1????? equ???? 13
R2????? equ???? 14
;
?include???????? "picreg.h"
;
B2_BCD? bcf???? STATUS,0??????????????? ; clear the carry bit
?movlw?? .16
?movwf?? count
?clrf??? R0
?clrf??? R1
?clrf??? R2
loop16? rlf???? L_byte
?rlf???? H_byte
?rlf???? R2
?rlf???? R1
?rlf???? R0
;
?decfsz? count
?goto??? adjDEC
?RETLW?? 0
;
adjDEC? movlw?? R2
?movwf?? FSR
?call??? adjBCD
;
?movlw?? R1
?movwf?? FSR
?call??? adjBCD
;
?movlw?? R0
?movwf?? FSR
?call??? adjBCD
;
?goto??? loop16
;
adjBCD? movlw?? 3
?addwf?? 0,W
?movwf?? temp
?btfsc?? temp,3????????? ; test if result > 7
?movwf?? 0
?movlw?? 30
?addwf?? 0,W
?movwf?? temp
?btfsc?? temp,7????????? ; test if result > 7
?movwf?? 0?????????????? ; save as MSD
?RETLW?? 0
;
;********************************************************************
;?????????????? Test Program
;*********************************************************************
main??? movlw?? 0FF
?movwf?? H_byte
?movwf?? L_byte????????? ; The 16 bit binary number = FFFF
?call??? B2_BCD????????? ; After conversion the Decimal Number
;?????????????????????????????? ; in R0,R1,R2 = 06,55,35
;
self??? goto??? self
;
?org???? 1FF
?goto??? main
;
?END