debugcon: add printf

2 files changed, 17 insertions, 3 deletions

diff --git a/src/debugcon.zig b/src/debugcon.zig
index e721a4d..6f8b8e7 100644
--- a/src/debugcon.zig
+++ b/src/debugcon.zig
@@ -1,11 +1,14 @@
-pub inline fn inb(port: u16) u8 {
+const fmt = @import("std").fmt;
+const Writer = @import("std").io.Writer;
+
+fn inb(port: u16) u8 {
     return asm volatile ("inb %[port], %[result]"
         : [result] "={al}" (-> u8),
         : [port] "{dx}" (port),
     );
 }
 
-pub fn outb(port: u16, data: u8) void {
+fn outb(port: u16, data: u8) void {
     asm volatile ("outb %[data], %[port]"
         :
         : [port] "{dx}" (port),
@@ -18,3 +21,14 @@ pub fn write(data: []const u8) void {
         outb(0xe9, x);
     }
 }
+
+pub const writer = Writer(void, error{}, callback){ .context = {} };
+
+fn callback(_: void, string: []const u8) error{}!usize {
+    write(string);
+    return string.len;
+}
+
+pub fn printf(comptime format: []const u8, args: anytype) void {
+    fmt.format(writer, format, args) catch unreachable;
+}
diff --git a/src/main.zig b/src/main.zig
index e647a81..55e30f8 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -11,7 +11,7 @@ export fn kmain() noreturn {
     console.puts("64-bit Yadka");
 
     // write debug data
-    debug.write("Hi!\n");
+    debug.printf("Hi from {p}\n", .{&kmain});
 
     while (true) {}
 }