DesignStart Eval : The number of INTISR in Cortex-M3

Hello all,

We use DesignStart Eval（AT421-MN-80001-r0p0-02rel0）for the first time.
And we use only CORTEXM3INTEGRATIONDS module, and peripheral circuits of CM3 are own user-logic.

Even if in this case, is the number of free userable INTISR is 19 (from 45 to 63)?
Or can use 64 (from 0 to 63)?

Hope this helps someone!