From ad805c698cd1c4d68d090f842fb14621c32ee8d6 Mon Sep 17 00:00:00 2001
From: David Li <li.davidm96@gmail.com>
Date: Fri, 8 Jan 2016 10:04:27 -0700
Subject: Refactor into multiple files

---
 src/system.rs | 67 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 src/system.rs

(limited to 'src/system.rs')

diff --git a/src/system.rs b/src/system.rs
new file mode 100644
index 0000000..faadb13
--- /dev/null
+++ b/src/system.rs
@@ -0,0 +1,67 @@
+use std;
+
+use rustv::isa;
+use rustv::memory::SharedMemory;
+use rustv::register_file::RegisterFile;
+use rustv::syscall;
+use rustv::trap::Trap;
+
+pub struct SyscallHandler<'a> {
+    memory: SharedMemory<'a>,
+}
+
+impl<'a> SyscallHandler<'a> {
+    pub fn new(memory: SharedMemory<'a>) -> SyscallHandler<'a> {
+        SyscallHandler {
+            memory: memory
+        }
+    }
+}
+
+impl<'a> SyscallHandler<'a> {
+    fn print(&mut self, registers: &mut RegisterFile) -> Option<Trap> {
+        let mut base = registers.read_word(isa::Register::X11);
+        let mut string = vec![];
+
+        loop {
+            let c = self.memory.borrow_mut().read_byte(base);
+
+            if let Ok(0x00) = c {
+                break;
+            }
+            else if let Ok(c) = c {
+                string.push(c);
+            }
+
+            base += 1;
+        }
+
+        let result = std::str::from_utf8(&string);
+        if let Ok(string) = result {
+            println!("{}", string);
+        }
+        else {
+            println!("Error printing string: not valid UTF-8: {:?}", result);
+        }
+        None
+
+    }
+}
+
+impl<'a> syscall::SyscallHandler for SyscallHandler<'a> {
+    // TODO: is trap really appropriate here?
+    fn syscall(&mut self, registers: &mut RegisterFile) -> Option<Trap> {
+        let syscall_number = registers.read_word(isa::Register::X10);
+
+        match syscall_number {
+            22 => {
+                self.print(registers)
+            }
+
+            _ => {
+                // TODO: some sort of error reporting
+                None
+            }
+        }
+    }
+}
-- 
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