MEMFILL
         PLA
         STA   RETADR
         PLA
         STA   RETADR+1
         PLA
         STA   :VALUE
         PLA
         STA   :ARYSZ
         PLA
         STA   :ARYSZ+1
         PLA
         STA   ADDR1      ; ZERO PAGE POINTER
         PLA              ; DEFINED IN
         STA   ADDR1+1    ; DECS
         LDA   :VALUE     ; GET VAL FOR FILL
         LDX   :ARYSZ+1   ; X=# OF PAGES TO DO
         BEQ   :PARTPG    ; BRANCH IF HIGHBYTE OF SZ = 0
         LDY   #0
:FULLPG
         STA   (ADDR1),Y
         INY              ; INC TO NEXT BYTE
         BNE   :FULLPG    ; BRANCH IF NOT DONE W/ PAGE
         INC   ADDR1+1    ; ADVANCE TO NEXT PAGE
         DEX
         BNE   :FULLPG    ; BRANCH IF NOT DONE W/ PAGES
:PARTPG
         LDX   :ARYSZ     ;GET # OF BYTES IN FINAL PAGE
         BEQ   :EXIT      ; BRANCH IF LOW BYTE = 0
         LDY   #0
:PARTLP
         STA   (ADDR1),Y  ; STORE VAL
         INY              ; INCREMENT INDEX
         DEX              ; DECREMENT COUNTER
         BNE   :PARTLP    ; BRANCH IF NOT DONE
:EXIT
         LDA   RETADR+1
         PHA
         LDA   RETADR
         PHA
         RTS
:VALUE   DS    1          ; FILL VALUE
:ARYSZ   DS    2          ; ARRAY SIZE