The LAPIC timer is programmed in one-shot mode with vector 32
(Board::TIMER_VECTOR_KERNEL). The timer frequency is measured using PIT
channel 2 as reference (50ms delay).
Disable PIT timer channel 0 since BIOS programs it to fire periodically.
This avoids potential spurious timer interrupts.
This patch contains the initial code needed to build and bootstrap the
base-hw kernel on x86 64-bit platforms. It gets stuck earlier
because the binary contains 64-bit instructions, but it is started in
32-bit mode. The initial setup of page tables and switch to long mode is
still missing from the crt0 code.
