bin8bcd.asm

PIC单片机开发的功能函数：加减乘除转换

;               8位BIN数转化为2位BCD数
;********************************************************************
;                  Binary To BCD Conversion Routine
;
;       This routine converts the 8 bit binary number in the W Register
; to a 2 digit BCD number.
;       The least significant digit is returned in location LSD and
; the most significant digit is returned in location MSD.
;
;   Performance :
;               Program Memory  :       10
;               Clock Cycles    :       81 (worst case when W = 63 Hex )
;                                          ( i.e max Decimal number 99 )
;*******************************************************************
;
LSD     equ     10
MSD     equ     11
;
;其它的寄存器自己定义
;
BinBCD  
clrf    MSD
	movwf   LSD
gtenth
  movlw   D'10'
	subwf   LSD,W
	BTFSS   STATUS,C
	goto    over
	movwf   LSD
	incf    MSD
	goto    gtenth
over    
retlw   0
;**********************************
;测试程序(注意用法,BIN数放在W里,结果放在MSD,LSD里)
;----------------------------------
main
    movlw   63              ; W reg = 63 Hex
	call    BinBCD          ; after conversion, MSD = 9 & LSD = 9
                            ; ( 63 Hex = 99 Decimal )

self    goto    self        ; 如不是测试程序,本句无用
;
	org     1FF
	goto    main
;
	END