Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronic Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

16 bit maths routines for F84

Status
Not open for further replies.

mypooka

Member level 1
Joined
Dec 30, 2001
Messages
41
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
351
16f84 maths

:lol:

maybe these are usefull for some newer people
i set these maths routines up for 16f84

16bit maths division, subtraction, multiplication!
hope these help someone!


list P = 16F84
include "p16F84.inc"
;
;
CBLOCK 0x0C
ACCaLO
ACCaHI

ACCbLO
ACCbHI

ACCcLO
ACCcHI

ACCdLO
ACCdHI
temp
sign
ENDC
;
;
;*******************************************************************
; Double Precision Division
;*******************************************************************
; Load constant values to ACCa & ACCb for testing
;-------------------
org 0h

movlw 0h
movwf ACCaHI ; the dividing number!
movlw d'10' ; after run! loads ACCa = FF= d15
movwf ACCaLO
;
movlw 015
movwf ACCbHI ; the number to be divided!
movlw 07C ; also the result of division
movwf ACCbLO ; load eg: 157C = d5500
;---------------
call D_divS ; remainder in ACCc
; remander =63
stop goto stop
;
;-------------
D_divS
call setup
clrf ACCcHI
clrf ACCcLO
dloop bcf STATUS,C
rlf ACCdLO, F
rlf ACCdHI, F
rlf ACCcLO, F
rlf ACCcHI, F
movf ACCaHI,W
subwf ACCcHI,W ;check if a>c
btfss STATUS,Z
goto nochk
movf ACCaLO,W
subwf ACCcLO,W ;if msb equal then check lsb
nochk btfss STATUS,C ;carry set if c>a
goto nogo
movf ACCaLO,W ;c-a into c
subwf ACCcLO, F
btfss STATUS,C
decf ACCcHI, F
movf ACCaHI,W
subwf ACCcHI, F
bsf STATUS,C ;shift a 1 into b (result)
nogo rlf ACCbLO, F
rlf ACCbHI, F
decfsz temp, F ;loop untill all bits checked
goto dloop
;
retlw 0
;*******************************************************************
;
setup movlw 0x10 ; for 16 shifts
movwf temp
movf ACCbHI,W ;move ACCb to ACCd
movwf ACCdHI
movf ACCbLO,W
movwf ACCdLO
clrf ACCbHI
clrf ACCbLO
retlw 0

END
;****************************************************************










list P = 16F84
include "p16F84.inc"

CBLOCK 0x0C

temp
ACCaLO ; was called product!
ACCaHI

ACCbLO
ACCbHI ; first x number

ACCcLO ; second number!
ACCcHI

ENDC





org 0h
;*************************************************
; multiply sub rutine!
;*************************************************
goto $ +4
clrf ACCaLO
clrf ACCaHI
nop
nop

clrf ACCaLO
clrf ACCaHI

movlw 0x0A
movwf ACCbLO ; lower 8bits of first number
movlw 0x00
movwf ACCbHI ; upper 8bits of first number

movlw 0x6F
movwf ACCcLO ; lower 8bits of second number
movlw 0x19
movwf ACCcHI ; upper 8bits of second number

movlw .16 ; Operating on 16 Bits
movwf temp

Loop ; Loop Here for Each Bit

rrf ACCbHI, f ; Shift the Multiplier down
rrf ACCbLO, f ; by one

btfss STATUS, C ; If the bit is set, add
goto Skip ; the Multiplicand to the
; "Product"
movf ACCcHI, w
addwf ACCaHI, f
movf ACCcLO, w
addwf ACCaLO, f
btfsc STATUS, C
incf ACCaHI, f

Skip ; Shift up Multiplicand and
bcf STATUS, C ; Loop Around
rlf ACCcLO, f
rlf ACCcHI, f

decfsz temp,F
goto Loop
;
; the result is in ACCaHI,ACCaLO

stop goto stop

end



list P = 16F84
include "p16F84.inc"

CBLOCK 0x0C
temp
ACCaLO ;
ACCaHI

ACCbLO
ACCbHI ; first number

ACCcLO ; second number!
ACCcHI

ACCdLO
ACCdHI

ENDC









;**************************************************
; subtract sub rutine!
;**************************************************
org 0h
;--------------------------
; test code for subtraction
;--------------------------

;--------------------

movlw 0x8A
movwf ACCaHI ; example numbers
movlw 0x06
movwf ACCaLO

movlw 0x8A
movwf ACCbHI
movlw 0x0A
movwf ACCbLO
;-------------------

;----------
movf ACCaHI,W ; Subtract the High Byte First
subwf ACCbHI,W ; b-a=c
movwf ACCcHI ; store the HI results
;----------

movf ACCaLO,W ; Subtract the Low Byte Next
subwf ACCbLO,W ; store the result in ACCbLO
movwf ACCcLO ; store the LO results

btfss STATUS, C ; Don't Dec high byte if carry Set
decf ACCcHI, F

iorwf ACCcHI, W ; Check for Equal to Zero
btfsc STATUS, Z ; If Not Zero, Jump Over
goto EqualLess ; Equals, Jump to the Code
btfsc ACCcHI, 7h ; If Number is Negative, execute
goto EqualLess ; if A>B go here! Else, Jump Over

great goto great ; if A<B go here!
;
; results are in ACCcHI and ACCcLO

EqualLess

stop goto stop ;

end

;
;
 

Status
Not open for further replies.
Toggle Sidebar

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top