; command line:  pmars -s 80 -l 20 xycalc.red
; generates potential xy pairs for the nano Q^4 qscan, stored as dat x,y

        org    eval

        xoff   equ -8

        upper  equ -8

        temp   equ xy-1
xy      dat    8-xoff,  8

loop    mov.a  #8-xoff, xy

eval    mov.f  xy,      temp    ; check x*y-xoff = x
        mul.x  xy,      temp
        sub    #xoff,   temp
        seq.ab xy,      temp
        jmp    next

        add.ba xy,      temp    ; check x*y+y in range
        slt.a  #-17,    temp
        slt.a  #7,      temp
        jmp    next

        sub.b  xy,      temp
        slt    #-5,     temp
        slt    #4-xoff, temp
ptr     jmp    next,    list

        mov.f  xy,      >ptr    ; store xy

next    slt.a  #upper,  xy      ; xloop
        jmp    eval,    }xy

        slt    #upper,  xy      ; yloop
        jmp    loop,    >xy

list    end