Add value directives and strings

.string, .zstring, .u64, .u32, .u16, .u8 are used before an ImmValue to
determine how the memory should be laid out for that value.

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

src/main.rs

@@ -31,7 +31,7 @@ fn main() -> Result<()> {
         }
     };
     let obj = vm::obj::obj::Object::try_from(&ast)?;
-    //dump(&obj)?;
+    dump(&obj)?;
     let mut vm = vm::vm::Vm::new();
     vm.load_object(obj, 1024 * 1024 * 64)?; // 64mb
     let status = vm.run()?;
@@ -45,16 +45,31 @@ fn dump(obj: &vm::obj::obj::Object) -> Result<()> {
     use vm::visit::VisitInst;
     let mut stdout = io::stdout();
     for section in &obj.sections {
-        let mut disasm = match section {
-            Section::Code { start, contents, .. } => {
-                vm::disassemble::Disassemble::new(&mut stdout, contents, *start)
+        match section {
+            Section::Data { start, contents, .. } => {
+                const WIDTH: usize = 4;
+                println!("data section at 0x{:08x}", start);
+                for (i, b) in contents.iter().enumerate() {
+                    if i % WIDTH == 0 {
+                        print!("{:08x} | ", ((*start as usize) + i));
+                    }
+                    print!("{:02x} ", b);
+                    if i % WIDTH == (WIDTH - 1) {
+                        println!();
+                    }
+                }
+                println!();
             }
-            Section::Meta { .. } | Section::Data { .. } => continue,
+            Section::Code { start, contents, .. } => {
+                println!("code section at 0x{:08x}", start);
+                let mut disasm = vm::disassemble::Disassemble::new(&mut stdout, contents, *start);
+                while !disasm.is_done() {
+                    disasm.visit_inst()?;
+                }
+                println!();
+            }
+            Section::Meta { .. } => continue,
         };
-        while !disasm.is_done() {
-            disasm.visit_inst()?;
-        }
-        println!();
     }
     Ok(())
 }