PIC单片机的BCD码处理程序

#define PAGE EJECT

TITLE "BCD Arithmetic Routines : Ver 1.0"

;************************************************

; BCD Arithmetic Routines

;************************************************

LIST columns=120, WRAP, L=0

include "17c42.h"

CBLOCK 0x20

Lbyte, Hbyte

R2, R1, R0 ;must maintain R2, R1, R0 sequence

count

Num1, Num2

ENDC

;

BCD equ Num1

Htemp equ Num1

Ltemp equ Num2

;

PAGE

ORG 0x0000

;*******************************************************************

; BCD Arithmetic Test Program

;*******************************************************************

;

main

setf Hbyte

setf Lbyte

; ; 16 bit binary num = 0xffff

call B2_BCD_Looped ; after conversion the Decimal Num

; ; in R0, R1, R2 = 06,55,35

setf Hbyte

setf Lbyte

call B2_BCD_Straight ; same as above, but straight line code

;

movlw 0x06

movwf R0

movlw 0x55

movwf R1

movlw 0x35

movwf R2 ; setf R0R1R2 = 65535

;

call BCDtoB ; after conversion Hbyte = 0xff

; ; and Lbyte = 0xff

movlw 0x99

movwf Num1

movlw 0x99

movwf Num2 ; setf Num1 = Num2 = 0x99 (max BCD)

;

call BCDAdd ; after addition, Num2 = 98

; ; and Num1 = 01 ( 99+99 = 198)

;

movlw 0x63 ; setf Wreg = 63 hex

call BinBCD ; after conversion, BCD = 99

; ; 63 hex = 99 decimal.

;

self goto self

;

PAGE

;*******************************************************************;

; Binary To BCD Conversion Routine (8 bit)

;

; This routine converts the 8 bit binary number in the W Reg

; to a 2 digit BCD number in location BCD( compacted BCD Code)

; 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 :62(worst case when W = 63 Hex )

; ( i.e max Decimal number 99 )

;*******************************************************************

;

BinBCD

clrf BCD

again

addlw -10

btfss _carry

goto swapBCD

incf BCD

goto again

swapBCD

addlw 10

swapf BCD

iorwf BCD

return

;

PAGE

;********************************************************************

; Binary To BCD Conversion Routine (16 Bit)

; (LOOPED Version)

;

; This routine converts a 16 Bit binary Number to a 5 Digit

; BCD Number.

;

; The 16 bit binary number is input in locations Hbyte and

; Lbyte with the high byte in Hbyte.

; 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:32

; Clock Cycles :750

;

;*******************************************************************;

;

B2_BCD_Looped

bsf _fs0

bsf _fs1 ; set fsr0 for no auto increment

;

bcf _carry

clrf count

bsf count,4 ; set count = 16

clrf R0

clrf R1

clrf R2

loop16a

rlcf Lbyte

rlcf Hbyte

rlcf R2

rlcf R1

rlcf R0

;

dcfsnz count

return

adjDEC

movlw R2 ; load R2 as indirect address ptr

movwf fsr0

call adjBCD

;

incf fsr0

call adjBCD

;

incf fsr0

call adjBCD

;

goto loop16a

;

adjBCD

movfp indf0,wreg

addlw 0x03

btfsc wreg,3 ; test if result > 7

movwf indf0

movfp indf0,wreg

addlw 0x30

btfsc wreg,7 ; test if result > 7

movwf indf0 ; save as MSD

return

;

;********************************************************************

; Binary To BCD Conversion Routine (16 Bit)

; (Partial Straight Line Version)

;

; This routine converts a 16 Bit binary Number to a 5 Digit

; BCD Number.

;

; The 16 bit binary number is input in locations Hbyte and

; Lbyte with the high byte in Hbyte.

; 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:44

; Clock Cycles :572

;

;*******************************************************************;

;

B2_BCD_Straight

bsf _fs0

bsf _fs1 ; set fsr0 for no auto increment

;

bcf _carry

clrf count

bsf count,4 ; set count = 16

clrf R0

clrf R1

clrf R2

loop16b

rlcf Lbyte

rlcf Hbyte

rlcf R2

rlcf R1

rlcf R0

;

dcfsnz count

return ; DONE

movlw R2 ; load R2 as indirect address ptr

movwf fsr0

; adjustBCD

movfp indf0,wreg

addlw 0x03

btfsc wreg,3 ; test if result > 7

movwf indf0

movfp indf0,wreg

addlw 0x30

btfsc wreg,7 ; test if result > 7

movwf indf0 ; save as MSD

;

incf fsr0

; adjustBCD

movfp indf0,wreg

addlw 0x03

btfsc wreg,3 ; test if result > 7

movwf indf0

movfp indf0,wreg

addlw 0x30

btfsc wreg,7 ; test if result > 7

movwf indf0 ; save as MSD

;

incf fsr0

; adjustBCD

movfp indf0,wreg

addlw 0x03

btfsc wreg,3 ; test if result > 7

movwf indf0

movfp indf0,wreg

addlw 0x30

btfsc wreg,7 ; test if result > 7

movwf indf0 ; save as MSD

;

goto loop16b

;

PAGE

;*********************************************************

; BCD To Binary Conversion

;

; This routine converts a 5 digit BCD number to a 16 bit binary

; number.

; The input 5 digit BCD numbers are asumed to be in locations

; R0, R1 & R2 with R0 containing the MSD in its right most nibble.

;

; The 16 bit binary number is output in registers Hbyte & Lbyte

; ( high byte & low byte repectively ).

;

; The method used for conversion is :

; input number X = abcde ( the 5 digit BCD number )

; X = (R0,R1,R2) = abcde = 10[10[10[10a+b]+c]+d]+e

;

; Performance :

; Program Memory:30

; Clock Cycles :112

;

;***********************************************;

;

mpy10b

andlw 0x0f

addwf Lbyte

btfsc _carry

incf Hbyte

mpy10a

bcf _carry ; multiply by 2

rlcf Lbyte,w

movwf Ltemp

rlcf Hbyte,w ; (Htemp,Ltemp) = 2*N

movwf Htemp

;

bcf _carry ; multiply by 2

rlcf Lbyte

rlcf Hbyte

bcf _carry ; multiply by 2

rlcf Lbyte

rlcf Hbyte

bcf _carry ; multiply by 2

rlcf Lbyte

rlcf Hbyte ; (Hbyte,Lbyte) = 8*N

;

movfp Ltemp,wreg

addwf Lbyte

movfp Htemp,wreg

addwfc Hbyte

return ; (Hbyte,Lbyte) = 10*N

;

;

BCDtoB

clrf Hbyte

movfp R0,wreg

andlw 0x0f

movwf Lbyte

call mpy10a ; result = 10a+b

;

swapf R1,w

call mpy10b ; result = 10[10a+b]

;

movfp R1,wreg

call mpy10b ; result = 10[10[10a+b]+c]

;

swapf R2,w

call mpy10b ; result = 10[10[10[10a+b]+c]+d]

;

movfp R2,wreg

andlw 0x0f

addwf Lbyte

btfsc _carry

incf Hbyte ; result = 10[10[10[10a+b]+c]+d]+e

return ; BCD to binary conversion done

;

PAGE

;***********************************************;

;

; Unsigned BCD Addition

;

; This routine performs a 2 Digit Unsigned BCD Addition

; It is assumed that the two BCD numbers to be added are in

; locations Num1 & Num2. The result is the sum of Num1+Num2

; and is stored in location Num2 and the overflow carry is returned

; in location Num1

;

; Performance :

; Program Memory: 5

; Clock Cycles : 5

;

;*****************************************;

;

BCDAdd

movfp Num1,wreg

addwf Num2,w ; perform binary addition

daw Num2 ; adjust for BCD addition

clrf Num1

rlcf Num1 ; set Num1 = carry bit

return

;

;******************************************************

;

END