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, 22 insertions, 0 deletions

diff --git a/real/real.ha b/real/real.ha
new file mode 100644
index 0000000..ee42523
--- /dev/null
+++ b/real/real.ha
@@ -0,0 +1,22 @@
+export type state = struct {
+	@offset(0) eax: u32,
+	@offset(4) ebx: u32,
+	@offset(8) ecx: u32,
+	@offset(12) edx: u32,
+	@offset(16) edi: u32,
+	@offset(20) esi: u32
+};
+
+export let regs: state;
+
+
+export fn clearregs() void = {
+	regs = state {
+		...
+	};
+};
+
+export @symbol("real.call") fn call(addr: u16) void;
+
+export @symbol("testt") fn testt() void;
+export @symbol("drive_read_lba") fn drive_read_lba() void;