preprologue ignored (vjasinski)

MPABX 2.35, XC16 1.24, WinXP, dsPIC33FJ64MC802I am trying to use the 'preprologue' directive to insert some asm code in an interrupt handler.void __attribute__ ((interrupt,no_auto_psv,preprologue("BSET LATB,3"))) _CNInterrupt(void)
Compiler gives war..