a) The instructions in DCR must be relocatable.
b) The instructions in DCR must not include a call instruction.
c) JTPR must not be targeted by any jump or call instruction.
-d) DCR must not straddle the border betweeen functions.
+d) DCR must not straddle the border between functions.
Anyway, these limitations are checked by the in-kernel instruction
decoder, so you don't need to worry about that.