; This program swaps the first element of an array of byte-length data with the last
; element, the 2nd element with 2nd to last, and so on.

data        equ $1000
prog        equ     $2000

        org     data
L       dc.b    $05
array       db      1,2,3,4,5

        org     prog
        ldb L
        ldx     #$0002
        idiv
        pshx
        puld
        exg A,B
        ldy     #$1000
        ldb     L
        aby
        ldx #array

loop        tsta
        beq done
        movb    0,Y,0,SP
        movb    0,X,1,Y-
        movb    0,SP,1,X+
        deca
        bne loop
done        swi
        end