Motorola Axiom CMD11E1 Betriebsanweisung PDF herunterladen (Seite 44)

44 CHAPTER 3. FUNCTIONS AND BIT MANIPULATIONS

ORG $D000

;; ALL THE DATA ITEMS GO HERE.$

;;;;;;;;;;;;;;;;;;;;;;;end of code ;;;;;;;;;;;;;;;;;;;;;;;;

3.9 Testing bits

Often we have to take a decision based on whether a bit is set or not in memory.

To test if one or more bits are set, we clear all other bits and see if the result is

zero. If so, none of these bits are set. If not, at least one of them was set. The

following program will print YES if bit #4 in memory location $00 is set. Or else

it will print NO.

;;;;;;;;;;;;;;;;;;;;;;;start of code ;;;;;;;;;;;;;;;;;;;;;;;;

;; Insert standard buffalo equates here

BIT4 EQU %00010000 ; THIS EQUATE MAKES THE CODE MORE READABLE

ORG $C100

JSR OUTCRLF *NEED THIS FOR OUTPUTS TO LINE UP!

JSR RAND

STAA $00

JSR PRBINARY *PRINT BEFORE

LDAA $00

ANDA #BIT4

BEQ NOPE

LDX #YESSTR

JSR OUTSTRG

SWI

NOPE

LDX #NOSTR

JSR OUTSTRG

SWI

;; INSERT THE CODE FOR CLRBIT4 SETBIT4 RAND AND PRBINARY HERE

ORG $D000

;; ALL THE DATA ITEMS GO HERE.$

YESSTR FCC /YES/

FCB 4

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Motorola Axiom CMD11E1 Betriebsanweisung Seite 44