Added Write system call

src/kernel/exception.rs

@@ -1,3 +1,5 @@
+use libc::printf;
+
 use crate::simulator::{machine::{ExceptionType, Machine}, error::{MachineOk, MachineError}};
 
 
@@ -37,7 +39,9 @@ pub const SC_SYS_TIME: u8 = 32 ;
 pub const SC_MMAP: u8 = 33;
 pub const SC_DEBUG: u8 = 34;
 
+pub const CONSOLE_OUTPUT: u8 = 1;
 
+// todo : returns new types, not just machine errors and machine ok
 pub fn call(exception: ExceptionType, machine: &Machine) -> Result<MachineOk, MachineError> {
 
     match exception {
@@ -64,7 +68,30 @@ fn syscall(machine: &Machine) -> Result<MachineOk, MachineError> {
         SC_CREATE => todo!(),
         SC_OPEN => todo!(),
         SC_READ => todo!(),
-        SC_WRITE => todo!(),
+        SC_WRITE => {
+
+            let address = machine.read_int_register(10);
+            let size = machine.read_int_register(11);
+            // openfileid or 1 (console)
+            let f = machine.read_int_register(12);
+
+            // load buffer
+            let mut buffer = "".to_string();
+            for i in 0..size {
+                match char::from_digit(machine.read_memory(1, (address + i) as usize) as u32, 2) {
+                    Some(c) => buffer.push(c),
+                    None => todo!() // Throw a proper error
+                }
+            }
+
+            if f as u8 == CONSOLE_OUTPUT {
+                println!("{}", buffer); // todo replace with console driver in the future
+            } else {
+                todo!("SC_WRITE to file is not yet implemented")
+            }
+
+            Ok(MachineOk::Ok)
+        },
         SC_SEEK => todo!(),
         SC_CLOSE => todo!(),
         SC_NEW_THREAD => todo!(),