A possible problem you might have is a misconfigured interrupt service routine in Timer8INT.asm.
When using the directive #pragma interrupt_handler
you need to make sure you're using the
right instruction to call the C interrupt service routine in your Timer8INT.asm ISR.
If this directive is defined a reti
instruction will be add to the end of that function which is incorrect if you use lcall
to call that C function from your Timer8INT.asm. In this case you actually need a simple ljmp
instruction to that C function.
When using directive #pragma interrupt_handler
Timer8INT.asm should have
_Timer8_ISR:
ljmp _myTimerInt
reti
Without directive #pragma interrupt_handler
Timer8INT.asm should have
_Timer8_ISR:
PRESERVE_CPU_CONTEXT
lcall _myTimerInt
RESTORE_CPU_CONTEXT
reti