Add Disassemble, fix bug in position calculation

* Disassemble structure can be used for dumping an object section
* Assembler position calculation was messing up, causing jump addresses
  to be wrong. This is fixed.

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

src/main.rs

@@ -1,7 +1,6 @@
 #![allow(dead_code)]
 
 mod common;
-//mod syn;
 mod vm;
 
 use std::{convert::TryFrom, env, fs, io, process};
@@ -32,10 +31,31 @@ fn main() -> Result<()> {
         }
     };
     let obj = vm::obj::obj::Object::try_from(&ast)?;
-    //println!("{:#?}", obj);
     let mut vm = vm::vm::Vm::new();
     vm.load_object(obj, 1024 * 1024 * 64)?; // 64mb
     let status = vm.run()?;
-    println!("status: {}", status);
+    println!("{}", status);
     Ok(())
 }
+
+
+    /*
+fn dump(obj: &Object) {
+    use vm::obj::obj::Section;
+    use vm::visit::VisitInst;
+    let mut stdout = io::stdout();
+    for section in &obj.sections {
+        let mut disasm = match section {
+            Section::Code { start, contents, .. }
+            | Section::Data { start, contents, .. } => {
+                vm::disassemble::Disassemble::new(&mut stdout, contents, *start)
+            }
+            Section::Meta { .. } => continue,
+        };
+        while !disasm.is_done() {
+            disasm.visit_inst()?;
+        }
+        println!();
+    }
+}
+    */