pic16f628a timer1 interupt wakeup from sleep
Okay, I've finally managed to solve the problem.
It is not code related - it's more of my devboard thing (ql-200).
As it seems, when you put PIC into sleep mode, oscillator uses much less power, and thus is shunted out by devboard programmer (which is connected to T1OSI/T1OSO pins).
Thus oscillator fails to generate in sleep mode.
Everything works fine when pulled out of the devboard.
For anyone to bump into this thread - above code works fine, and could be used for test purposes.