I have continued to make good progress since my midterm report. All the kernel functionality except for user debugging is implemented, and I have ported a basic set of drivers, including PCI, disk drivers, BFS and PS/2 input. For most drivers, porting is just a matter of fixing compiler warnings. For some, there are 64-bit issues which make porting more difficult. For example, the USB stack will require a bit more work as it currently assumes that addr_t is 32-bit everywhere.
This is a companion discussion topic for the original entry at https://www.haiku-os.org/blog/xyzzy/2012-08-04_x86_64_port_three_quarter_term_report/