Most of changes were moving around where macros were defined, plus the
following:
- Remove requirement for floating point on RV64 to support booting
monitor core on U54 SoC.
- Add support for Debug LEDs on HiFive Unleashed Board
Very little needed to port except to conditionalize some assembly in the
context switch and exception code. Mostly needed to move build system
stuff around and add a new project.
The virt machine is a generic target, much like the arm virt machine.
Intended to be simple to use and a good target to run large systems like
linux on. At the moment simply support booting and simple uart and timer
support.
-added support for bringing up the clocks and setting up the gpio bits
before starting the uart.
-add a proper target init routine
-add scripts to flash board via openocd
-fixed bug in riscv interrupt save state where it wasn't saving mstatus
on irq entry.
-comment out cycle enabling, not implemented on this core
Currently targets qemu's sifive_e machine, which is a split flash/ram
machine, much like the Sifive HiFive1. Untested as of yet on a real
HiFive1.
Basic support including interrupts and architectural timers in place.
