boot: longmode to realmode stub

This is the initial commit to the repo. It adds all the code.
The last proper thing that I got working before committing is
calling real mode functions from long mode using a stub.
Next up, I would like to implement a disk reader abstraction over
the BIOS in order to read form partitions (most notably FAT32).

1 files changed, 1 insertions, 0 deletions

diff --git a/rt/test.ha b/rt/test.ha
new file mode 100644
index 0000000..a9a03a3
--- /dev/null
+++ b/rt/test.ha
@@ -0,0 +1 @@
+export @symbol("real_call") fn real_call() void;