Add assembler and execution logic

Most everything works, but there's one small bug with the execution
involving jumps - still have to figure that one out.

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

src/vm/obj/syn/ast.rs

@@ -1,4 +1,7 @@
-use crate::vm::reg::Reg;
+use crate::vm::{
+    inst,
+    reg::Reg,
+};
 
 #[derive(Debug, Clone)]
 pub enum SectionDef {
@@ -8,7 +11,7 @@ pub enum SectionDef {
 
 #[derive(Debug, Clone)]
 pub struct MetaSection {
-    pub values: Vec<MetaLine>,
+    pub lines: Vec<MetaLine>,
 }
 
 #[derive(Debug, Clone)]
@@ -20,10 +23,27 @@ pub struct MetaLine {
 #[derive(Debug, Clone)]
 pub struct DataSection {
     pub name: String,
-    pub org: Option<SectionOrg>,
+    pub org: SectionOrg,
     pub lines: Vec<DataLine>,
 }
 
+impl DataSection {
+    pub fn exports(&self) -> impl Iterator<Item=&str> {
+        self.lines.iter()
+            .filter_map(|line| if let DataLine::Export(s) = line {
+                Some(s.as_str())
+            } else {
+                None
+            })
+    }
+
+    pub fn len(&self) -> usize {
+        self.lines.iter()
+            .map(DataLine::len)
+            .sum()
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum SectionOrg {
     Start(u64),
@@ -38,6 +58,16 @@ pub enum DataLine {
     Label(String),
 }
 
+impl DataLine {
+    pub fn len(&self) -> usize {
+        match self {
+            DataLine::ValueDef(v) => v.len(),
+            DataLine::Inst(i) => i.len(),
+            DataLine::Export(_) | DataLine::Label(_) => 0,
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum ValueDef {
     Int(u64),
@@ -45,6 +75,16 @@ pub enum ValueDef {
     ZString(String),
 }
 
+impl ValueDef {
+    pub fn len(&self) -> usize {
+        match self {
+            ValueDef::Int(_) => 8,
+            ValueDef::String(s) => 8 + s.as_bytes().len(),
+            ValueDef::ZString(s) => s.as_bytes().len() + 1,
+        }
+    }
+}
+
 #[derive(Debug, Clone)]
 pub enum Value {
     Int(u64),
@@ -52,7 +92,34 @@ pub enum Value {
     Name(String),
     Here,
     //Array(Vec<Value>),
-    //Deref(Value, Size
+    //Deref(Value, IntSize),
+}
+
+impl Value {
+    pub fn len(&self) -> usize {
+        match self {
+            // TODO : immediate int sizes
+            Value::Int(_) => 8,
+            Value::Reg(_) => 1,
+            Value::Name(_) => 8,
+            Value::Here => 8,
+        }
+    }
+    
+    pub fn dest_encoding(&self) -> Option<u8> {
+        match self {
+            Value::Int(_) | Value::Name(_) | Value::Here => None,
+            Value::Reg(_) => Some(inst::DEST_REG),
+        }
+    }
+
+    pub fn source_encoding(&self) -> u8 {
+        match self {
+            Value::Int(_) => inst::SOURCE_IMM64,
+            Value::Reg(_) => inst::SOURCE_REG,
+            Value::Name(_) | Value::Here => inst::SOURCE_IMM64,
+        }
+    }
 }
 
 #[derive(Debug, Clone)]
@@ -80,3 +147,32 @@ pub enum Inst {
     Nop,
     Dump,
 }
+
+impl Inst {
+    pub fn len(&self) -> usize {
+        match self {
+            Inst::Add(v1, v2)
+                | Inst::Sub(v1, v2)
+                | Inst::Mul(v1, v2)
+                | Inst::Div(v1, v2)
+                | Inst::Mod(v1, v2)
+                | Inst::And(v1, v2)
+                | Inst::Or(v1, v2)
+                | Inst::Xor(v1, v2)
+                | Inst::Shl(v1, v2)
+                | Inst::Shr(v1, v2)
+                | Inst::INeg(v1, v2)
+                | Inst::Inv(v1, v2)
+                | Inst::Not(v1, v2)
+                | Inst::CmpEq(v1, v2)
+                | Inst::CmpLt(v1, v2)
+                | Inst::Mov(v1, v2) => { 3 + v1.len() + v2.len() }
+            Inst::Jmp(v)
+                | Inst::Jz(v)
+                | Inst::Jnz(v) => { 3 + v.len() }
+            Inst::Halt
+                | Inst::Nop
+                | Inst::Dump => { 2 }
+        }
+    }
+}

src/vm/obj/syn/parser.y

@@ -7,8 +7,8 @@ SectionDefs -> Vec<SectionDef>:
     ;
 
 SectionDef -> SectionDef:
-      'DIR_META' MetaBlock { SectionDef::Meta(MetaSection { values: $2 }) }
-    | 'DIR_SECTION' Name MaybeSectionOrg DataBlock {
+      'DIR_META' MetaBlock { SectionDef::Meta(MetaSection { lines: $2 }) }
+    | 'DIR_SECTION' Name SectionOrg DataBlock {
         SectionDef::Data(DataSection {
             name: $2,
             org: $3,
@@ -27,11 +27,6 @@ MetaLines -> Vec<MetaLine>:
 
 MetaLine -> MetaLine: Name 'COLON' Value { MetaLine { name: $1, value: $3 } };
 
-MaybeSectionOrg -> Option<SectionOrg>:
-      SectionOrg { Some($1) }
-    | { None }
-    ;
-
 SectionOrg -> SectionOrg:
       Int { SectionOrg::Start($1) }
     | Int 'DOTDOT' Int { SectionOrg::StartEnd($1, $3) }