ECE 331 Example ASM Code

;Simple AND example (A.Mason Feb 10)
;Function: AND value in accA with value in program memory and store to memory
;Address mode for each instruction shown in comments
;version1: no labels
           ORG    $4000
           LDAA     #$0F        ;immediate
           ANDA     #$F0        ;immediate
           STAA     $5550       ;extended
           SWI
           END


;Simple AND example (A.Mason Feb 10)
;Function: AND value in accA with value in memory and store to memory
;Address mode for each instruction shown in comments
;version2: uses labels and equates, different values than version1
           ORG    $4000
Num1       EQU    $AA
Num2       EQU    $55
Result     EQU    $5550          
           LDAA     #Num1        ;immediate
           ANDA     #Num2        ;immediate
           STAA     Result       ;extended
           SWI
           END


;Simple AND example (A.Mason Feb 10)
;Function: AND value in accA with value in memory and store to memory
;Address mode for each instruction shown in comments
;version3: uses data storage and gets operands from memory
           ORG    $4000
           LDAA     Num1        ;extended
           ANDA     Num2        ;extended
           STAA     Result       ;extended
           SWI      ;stop
;data storage
           ORG    $5550
Num1       FCB    $FA
Num2       FCB    $5F
Result     FCB    $00   ;initialize result byte [5552] to 00
           END

;Simple AND example (A.Mason Feb 10)
;Function: AND value in accA with value in memory and store to memory
;Address mode for each instruction shown in comments
;version4: uses index address mode to store result
           ORG    $4000
           LDX    #Result       ;load addr of result in IX
           LDAA     Num1        ;extended
           ANDA     Num1+1      ;extended
           STAA     0,X         ;indexed
           SWI      ;stop
;data storage
      ORG    $5550
Num1       FCB    $AF
Num2       FCB    $FA
Result     FCB    $00   ; initialize result byte [5552] to 00
           END


;ECE331 Simple Summation (A.Mason Feb 10)
;add series of numbers beginning at 'nums'
;number of values added set by value in 'count'
;values must be small to avoid overflow; 'count' must be < 10
;requires indexed addressing; to simplify code, numbers added in reverse order
	org	$4000
	ldab	count     ;# of numbers to add
        decb              ;# of additions is 1 less than # of numbers
        ldx     #nums     ;addr for nums
        ldaa    sum       ;load starting sum
again   adda    b,x
        decb              ;decrement counter
        bpl     again     ;if b >= zero, add another
        staa    sum    
	swi
	org	$6000
count	fcb     $03
nums	fcb	1,2,3,4,5,6,7,8,9,10
sum	fcb	$F0     ;previous sum -random value
	end


; ECE331 Example of SET/CLR Bit and Branch Instructions
; program will read data and set lower nibble to %0011
; until odd value is read
        ORG     $4000
	LDAA	#00	; initialize index offset byte
	LDX	#DATA	; initialize index reference register
TOP	BRSET   A,X,$01,ODD	;end if odd value
	BSET	A,X,%00000011
	BCLR	A,X,%00001100
	LDAB	A,X
	INCA
	BRA	TOP
ODD	SWI		;end
; data storage
	ORG	$6000
DATA	FCB	$EE, $DC, $D0, $F4
	FCB	$80, $00, $55, $22
	FCB	$AA
	END

; ECE331 Example of Branches
; program will copy a list of data at HERE to THERE
; number of bytes to copy set by BYTES
HERE    EQU     $2000
THERE   EQU     $2020
BYTES   EQU     $06
        ORG     $1000
        LDAB	#$00 	;initialize item counter
	LDX	#HERE 	;initialize index reg as memory pointers
        LDY	#THERE
LOOP    LDAA    0,X  ;using indexed addressing
        STAA    0,Y
        INCB            ;increment counter
        CMPB    #BYTES  ;check for end of list
	BEQ 	DONE 	;if we are done
        INX             ;increment index registers
        INY
	BRA	LOOP	;continue at top
DONE    SWI             ;use SWI for any program that stops running
        END
; data storage
       ORG    HERE
       FCB    $10,$11,$12,$13,$14,$15,$16
       ORG    THERE
       RMB    BYTES    ;reserve locations to copy data


;Code to illustrate difference between program and data memory
;and describe difference between instruction, directives, and opcodes
;FUNCTION: Copy data from D_REC to D_CPY. Counts number of data bytes
;  in each record (record ends with 01) & stores count in RESULTS. Supports
;  up to 10 records and up to 32 data bytes
;
;***begin data block definition
	ORG	$6000; define data records
D_REC	FCB	$AA,$BB,$CC,$FF,$EE,$01
	FCB	$A1,$B2,$C3,$F4,$01
	FCB	$81,$72,$63,$54,$45,$E5,$01
RESULT	RMB	$0A; reserve 10 addrs. for results
D_CPY	RMB	$10; reserve 32 addrs. for copy
;
;***begin main program
	ORG	$4000
	LDS	#$8000
	LDX	#D_REC
	LDY	#D_CPY
	LDAA	#$0
	PSHA	;initialize # records
LOOP	LDAB	0,X
	STAB	0,Y
	CMPB	#$01
	BEQ	ENDLP
	INX
	INY
	INCA
	BRA	LOOP
ENDLP	PULB
	PSHY
	LDY	#RESULT
	STAA	B,Y
	PULY	; restore Y
	INCB
	PSHB	; store updated # records
	CPX	#RESULT
	BEQ	DONE	; at end of records?
	INX
	INY
	CLRA
	BRA	LOOP
;end of program
DONE	TBA; copy # records to accA
	END