feat: basic keyboard driver + tester shell

1 files changed, 25 insertions, 0 deletions

diff --git a/boot/port.zig b/boot/port.zig
new file mode 100644
index 0000000..05668d3
--- /dev/null
+++ b/boot/port.zig
@@ -0,0 +1,25 @@
+// x86 port I/O
+//
+// these are pretty important cause all drivers which rely
+// on serial rely on these 2 instructions so
+
+pub inline fn outb(port: u16, val: u8) void {
+    asm volatile ("outb %[val], %[port]"
+        :
+        : [val] "{al}" (val),
+          [port] "N{dx}" (port),
+    );
+}
+
+pub inline fn inb(port: u16) u8 {
+    return asm volatile ("inb %[port], %[result]"
+        : [result] "={al}" (-> u8),
+        : [port] "N{dx}" (port),
+    );
+}
+
+// a throwaway write to an unused port, ~1us. some 8259s need a beat between
+// back-to-back command writes on slow hardware; harmless on QEMU.
+pub inline fn wait() void {
+    outb(0x80, 0);
+}