- the PIC master and slave irq handlers don't pass the irq hook pointer but just
the irq number. It gives a little bit more information to the C handler as the
irq number is not lost
- the irq code path is more achitecture independent. i386 hw interrupts are
called irq and whereever the code is arch independent enough hw_intr_
functions are called to mask/unmask interrupts
- the legacy PIC is not the only possible interrupt controller in the x86 world,
therefore the intr_(un)mask functions were renamed to signal their
functionality explicitly. APIC will add their own.
- masking and unmasking PIC interrupt lines is removed from assembler and all
the functionality is rewriten in C and moved to i8259.c
- interrupt handlers have to unmask the interrupt line if all irq handlers are
done. Assembler does not do it anymore
