VDP routine YMMM appears to be incorrect

[suborb]

There's this bit of code:

        LD      A,L                     ;make NY and DIY
        SUB     A

To make it work (at least for my usecase), this should be:

        LD      A,L                     ;make NY and DIY
        SUB     E

For reference, I'm scrolling the screen up by 8 pixel rows:

    ld      bc,0
    ld      l,8
    ld      e,192
    ld      d,2
    call    ymmm