feat(assembler): Add instruction collapse code gen step

3 files changed, 53 insertions, 9 deletions

diff --git a/assembler/src/parser/code_gen.rs b/assembler/src/parser/code_gen.rs
index 375a8cb..dd1b872 100644
--- a/assembler/src/parser/code_gen.rs
+++ b/assembler/src/parser/code_gen.rs
@@ -1,4 +1,4 @@
-use super::{ Program, Address };
+use super::{ Program, Address, Instruction };
 
 impl Program {
     pub(crate) fn remove_definition_addresses(&mut self) {
@@ -10,4 +10,24 @@ impl Program {
             }
         }
     }
+
+    pub(crate) fn collapse_instructions(&mut self) {
+        let mut collapsed = Vec::new();
+        let mut update_addrs = Vec::new();
+
+        for instr in &mut self.instructions {
+            update_addrs.push(collapsed.len());
+            collapsed.extend(instr.collapse());
+        }
+
+        for instr in &mut self.instructions {
+            for arg in &mut instr.args {
+                if let Address::Instruction(num) = arg {
+                    *arg = Address::Instruction(update_addrs[*num]);
+                }
+            }
+        }
+
+        self.instructions = collapsed;
+    }
 }
diff --git a/assembler/src/parser/instruction.rs b/assembler/src/parser/instruction.rs
index e69de29..8c8e8aa 100644
--- a/assembler/src/parser/instruction.rs
+++ b/assembler/src/parser/instruction.rs
@@ -0,0 +1,23 @@
+use super::{ Instruction, Address };
+
+impl Instruction {
+    fn new_subleq(a: &Address, b: &Address, c: &Address) -> Instruction {
+        Instruction {
+            name: "subleq".to_string(),
+            args: vec![a.clone(), b.clone(), c.clone()],
+        }
+    }
+
+    pub(crate) fn collapse(&mut self) -> Vec<Instruction> {
+        self.name = self.name.to_lowercase();
+        static Z: Address = Address::Memory(0);
+
+        match &*self.name {
+            "subleq" | "add" | "mult" => vec![self.clone()],
+            "jmp" => vec![
+                Instruction::new_subleq(&Z, &Z, &self.args[0]),
+            ],
+            _ => panic!("Unknown instruction {}!", self.name),
+        }
+    }
+}
diff --git a/assembler/src/parser/mod.rs b/assembler/src/parser/mod.rs
index af78478..5dbedf6 100644
--- a/assembler/src/parser/mod.rs
+++ b/assembler/src/parser/mod.rs
@@ -1,13 +1,15 @@
 mod code_gen;
 mod syntax;
+mod instruction;
 
 use std::collections::HashMap;
 use crate::Word;
 
 #[derive(Debug, Default)]
-pub(crate) struct Instruction {
-    name: String,
-    args: Vec<Address>,
+pub(crate) struct Program {
+    definitions: HashMap<String, Address>,
+    constants: Vec<Word>,
+    instructions: Vec<Instruction>,
 }
 
 #[derive(Debug, Default, PartialEq, Eq, Clone)]
@@ -28,9 +30,8 @@ impl Address {
     }
 }
 
-#[derive(Debug, Default)]
-pub(crate) struct Program {
-    definitions: HashMap<String, Address>,
-    constants: Vec<Word>,
-    instructions: Vec<Instruction>,
+#[derive(Debug, Default, Clone)]
+pub(crate) struct Instruction {
+    name: String,
+    args: Vec<Address>,
 }