print SYSCALL works

ableos/src/wasm_jumploader/host_functions.rs

@@ -8,7 +8,7 @@ const ADD_FUNC_INDEX: usize = 0;
 const GET_TIME_INDEX: usize = 2;
 const GET_RANDOM_INDEX: usize = 3;
 const GET_INPUT_INDEX: usize = 4;
-const PRINT_CLEVER_HACK: usize = 5;
+const PRINT_CHAR: usize = 6;
 const SEND_SIGNAL_INDEX: usize = 1;
 
 pub struct HostExternals;
@@ -100,8 +100,8 @@ impl HostExternals {
                 true
             }
 
-            PRINT_CLEVER_HACK => {
-                let (params, ret_ty): (&[ValueType], Option<ValueType>) = (&[ValueType::I64], None);
+            PRINT_CHAR => {
+                let (params, ret_ty): (&[ValueType], Option<ValueType>) = (&[ValueType::I32], None);
                 if params.len() != signature.params().len() {
                     return false;
                 }
@@ -178,20 +178,12 @@ impl Externals for HostExternals {
                 Ok(Some(ret))
             }
 
-            PRINT_CLEVER_HACK => {
-                // println!("SYSCALL: print clever hack");
-
-                let combinated = args.nth_checked::<u64>(0).unwrap().to_le_bytes();
-
-                for x in combinated.iter() {
-                    let chr = *x as char;
-                    print!("{}", chr);
-                }
-
-                println!("\n");
+            PRINT_CHAR => {
+                let chr: u8 = args.nth_checked(0)?;
+                trace!("SYSCALL: print: {}", chr);
+                print!("{}", char::from(chr));
                 Ok(None)
             }
-
             _ => {
                 error!("Unimplemented function at {}", index);
                 Err(Trap::new(wasmi::TrapKind::Unreachable))
@@ -208,7 +200,7 @@ impl ModuleImportResolver for HostExternals {
             "get_time" => GET_TIME_INDEX,
             "get_random" => GET_RANDOM_INDEX,
             "get_input" => GET_INPUT_INDEX,
-            "print_clever_hack" => PRINT_CLEVER_HACK,
+            "print_char" => PRINT_CHAR,
             _ => {
                 return Err(Error::Instantiation(format!(
                     "Export {} not found",