A little correction. It is better to use a ftable
with zero(s) at the end, and

ginstab ftgen 0, 0, 4, -2, 143, 221, 39
; ginstab ftgen 0, 0, 8, -2, ia, ib, ic, id
; etc

opcode turnoff_all, 0, ii
  imode, irelease xin
  kndx init 0
  kinsno table kndx, ginstab
  if (kinsno > 0) then
    turnoff2 kinsno, imode, irelease
  else
    turnoff
  endif
  kndx = kndx + 1
endop