Move DRAM to high addresses

Refactor pk, bbl, machine into separate libraries

Yuck.

Fix struct stat size mismatch for RV32

Fix macros for emulating atomic operations (--disable-atomics).

Add ftruncate syscall

Update to new privileged spec

Support linkat, unlinkat, mkdirat syscalls

Also, old-style syscalls e.g. open are now implemented with e.g. openat.

Increased max number of files,fds statically supported by pk.

The SPECINT benchmark 445.gobmk reads in a lot of files and would
sometimes fail due to being unable to open more files.

Add file reference counting sanity check

Add several syscalls, and move syscall header file from newlib
syscalls added (openat, access, accessat, faccessat, etc.)

Use atomic_cas instead of __sync_bool_compare_and_swap

Abandon MIPS convention for indicating syscall errors in register a3

Update to new privileged ISA

Support Linux ABI and (optionally) virtual memory

add BSD license

new supervisor mode

temporary undoing of renaming

Renamed packages

[pk] made PK smaller

[sim,pk] cleanups & initial virtual memory support

[pk] fixed lseek syscall

[pk,fesvr] pk now loads elfs itself

this allows it to detect 32b binaries

[pk] send stdout/stderr to both fesvr and debug console

[pk] improved performance of fp emulation

[pk,fesvr] improved proxykernel build system

Now uses a modified MCPPBS. Add --host=riscv to configure path.

Front-end server now just searches PATH for riscv-pk, so just install the pk
to somewhere in your path.