- implementation of <var> <op> = <expr> type statements such as `x +=

5`
- implementation of logical and shift operations in parser and codegen.
- implementation of sizeof keyword as unary operator

in progress (non functional)
- implementation of prefix and postfix inc/dec operators

- array access by index (implemented, untested as arrays aren't
  implemented yet). essentially just a pointer write with offset.
- struct/member access (parsing implemented, untested.)

assembler/src/assembler/codegen.rs

@@ -223,19 +223,31 @@ fn build_shift_instruction(
     opcode: Opcode,
     args: &[crate::assembler::model::Token],
 ) -> Result<Instruction, AssembleError> {
-    let Some(reg_token) = args.first() else {
+    let Some(src_reg) = args.first() else {
         return Err(AssembleError::MissingArgument(0));
     };
-    let Some(amount_token) = args.get(1) else {
+    let Some(r_shamt) = args.get(1) else {
+        return Err(AssembleError::MissingArgument(0));
+    };
+    let Some(i_shamt) = args.get(2) else {
+        return Err(AssembleError::MissingArgument(1));
+    };
+    let Some(dest_reg) = args.get(3) else {
         return Err(AssembleError::MissingArgument(1));
     };
 
-    let reg = expect_token!(reg_token, Register)?;
+    let src = expect_token!(src_reg, Register)?;
-    let amount = expect_token!(amount_token, Immediate)? as u8;
+    let r_shamt = expect_token!(r_shamt, Register)?;
+    let i_shamt = expect_token!(i_shamt, Immediate)? as u8;
+    let dest = expect_token!(dest_reg, Register)?;
 
     match opcode {
-        Opcode::Shl => Ok(Instruction::ShiftLeft(args!(R, sr1: reg, shamt: amount))),
+        Opcode::Shl => Ok(Instruction::ShiftLeft(
-        Opcode::Shr => Ok(Instruction::ShiftRight(args!(R, sr1: reg, shamt: amount))),
+            args!(R, sr1: src, sr2: r_shamt, shamt: i_shamt, dr: dest),
+        )),
+        Opcode::Shr => Ok(Instruction::ShiftRight(
+            args!(R, sr1: src, sr2: r_shamt, shamt: i_shamt, dr: dest),
+        )),
         _ => unreachable!(),
     }
 }

assembler/src/assembler/parser.rs

@@ -1,5 +1,6 @@
 use std::path::{Path, PathBuf};
 
+use crate::assembler::TokenType;
 use crate::{assembler::AssembleError, expect_token, expect_type, node};
 
 use crate::assembler::model::{Node, Opcode, Token};
@@ -114,7 +115,8 @@ impl Parser {
 
                 let mut offset = Token::Immediate(0);
                 if let Ok(next) = self.peek_next()
-                    && expect_type!(next, Immediate).is_ok() {
+                    && expect_type!(next, Immediate).is_ok()
+                {
                     offset = self.next()?;
                 }
 
@@ -125,7 +127,8 @@ impl Parser {
                 let dest = expect_type!(self.next()?, Register, Symbol)?;
                 let mut offset = Token::Immediate(0);
                 if let Ok(next) = self.peek_next()
-                    && expect_type!(next, Immediate).is_ok() {
+                    && expect_type!(next, Immediate).is_ok()
+                {
                     offset = self.next()?;
                 }
                 args = vec![base, dest, offset];
@@ -146,15 +149,49 @@ impl Parser {
             }
 
             Opcode::Not | Opcode::Cmp => {
-                let reg1 = expect_type!(self.next()?, Register, Symbol)?;
+                let src = expect_type!(self.next()?, Register, Symbol)?;
-                let reg2 = expect_type!(self.next()?, Register, Symbol)?;
+                let dest = expect_type!(self.next()?, Register, Symbol)?;
-                args = vec![reg1, reg2];
+                args = vec![src, dest];
             }
-
             Opcode::Shl | Opcode::Shr => {
-                let reg = expect_type!(self.next()?, Register, Symbol)?;
+                let src = expect_type!(self.next()?, Register, Symbol)?;
-                let num = expect_type!(self.next()?, Immediate)?;
+
-                args = vec![reg, num];
+                // First operand after src: could be immediate or register
+                let first = self.next()?;
+
+                let (r_shamt, i_shamt) = match first {
+                    Token::Register(_) => (
+                        first,
+                        if let Ok(tok) = self.peek_next() {
+                            if expect_type!(tok, Immediate).is_ok() {
+                                self.next()?
+                            } else {
+                                Token::Immediate(0)
+                            }
+                        } else {
+                            Token::Immediate(0)
+                        },
+                    ),
+                    Token::Immediate(_) => (Token::Register(Register::Zero), first),
+                    _ => {
+                        return Err(AssembleError::UnexpectedToken(
+                            first,
+                            TokenType::Immediate,
+                        ));
+                    }
+                };
+
+                let dest = if let Ok(tok) = self.peek_next() {
+                    if expect_type!(tok, Register).is_ok() {
+                        self.next()?
+                    } else {
+                        src.clone() // Default to src if no dest specified
+                    }
+                } else {
+                    src.clone() // Default to src if no dest specified
+                };
+
+                args = vec![src, r_shamt, i_shamt, dest];
             }
 
             Opcode::Inc | Opcode::Dec => {

common/src/instructions.rs

@@ -69,7 +69,7 @@ pub enum Register {
     Idr,
     Mmr,
     Zero,
-    NoReg,
+    Null, // Invalid - Triggers a fault if accessed
 
     // system registers - can't be written to by instructions.
     Mar,
@@ -106,7 +106,7 @@ impl Register {
 
 impl Default for Register {
     fn default() -> Self {
-        Self::NoReg
+        Self::Null
     }
 }
 
@@ -144,7 +144,7 @@ impl TryFrom<u8> for Register {
             0x14 => Self::Idr,
             0x15 => Self::Mmr,
             0x16 => Self::Zero,
-            0x17 => Self::NoReg,
+            0x17 => Self::Null,
             0x18 => Self::Mar,
             0x19 => Self::Mdr,
             0x1A => Self::Sts,
@@ -183,7 +183,7 @@ impl TryFrom<&str> for Register {
             "idr" => Ok(Self::Idr),
             "mmr" => Ok(Self::Mmr),
             "zero" => Ok(Self::Zero),
-            "null" => Ok(Self::NoReg),
+            "null" => Ok(Self::Null),
             "pcx" => Ok(Self::Pcx),
             _ => Err(RegisterParseError::InvalidName(value.to_string())),
         }
@@ -216,7 +216,7 @@ impl std::fmt::Display for Register {
             Self::Idr => write!(f, "idr"),
             Self::Mmr => write!(f, "mmr"),
             Self::Zero => write!(f, "zero"),
-            Self::NoReg => write!(f, "noreg"),
+            Self::Null => write!(f, "null"),
             Self::Mar => write!(f, "mar"),
             Self::Mdr => write!(f, "mdr"),
             Self::Sts => write!(f, "sts"),

common/src/instructions/encode.rs

@@ -8,9 +8,9 @@ pub trait Encode {
 /// Encodes a zero argument instruction.
 fn encode_no_args(opcode: u8) -> u32 {
     let opcode = u32::from(opcode);
-    let sr1 = Register::NoReg as u32;
+    let sr1 = Register::Null as u32;
-    let sr2 = Register::NoReg as u32;
+    let sr2 = Register::Null as u32;
-    let dr = Register::NoReg as u32;
+    let dr = Register::Null as u32;
     let shamt = 0;
 
     (opcode << 26) | (sr1 << 21) | (sr2 << 16) | (dr << 11) | (shamt << 6)

common/src/instructions/encode/tests.rs

@@ -2,7 +2,7 @@ use crate::prelude::*;
 
 #[test]
 fn test_encode_nop() {
-    let no_reg = Register::NoReg as u32;
+    let no_reg = Register::Null as u32;
     let no_op = u32::from(Instruction::Nop.opcode());
 
     let expected = (no_op << 26) | (no_reg << 21) | (no_reg << 16) | (no_reg << 11);
@@ -15,7 +15,7 @@ fn test_encode_nop() {
 fn test_encode_mov() {
     let rg0 = Register::Rg0 as u32;
     let rg1 = Register::Rg1 as u32;
-    let no_reg = Register::NoReg as u32;
+    let no_reg = Register::Null as u32;
 
     let instruction = Instruction::Mov(RTypeArgs::new(
         Some(Register::Rg0),
@@ -53,7 +53,7 @@ fn test_encode_load_byte() {
 #[test]
 fn test_encode_shift_left_shamt() {
     let rg0 = Register::Rg0 as u32;
-    let no_reg = Register::NoReg as u32;
+    let no_reg = Register::Null as u32;
 
     let shift_amount = 5;
 
@@ -80,7 +80,7 @@ fn test_encode_shift_left_shamt() {
 fn test_encode_shift_left_reg() {
     let rg0 = Register::Rg0 as u32;
     let rg1 = Register::Rg1 as u32;
-    let no_reg = Register::NoReg as u32;
+    let no_reg = Register::Null as u32;
 
     let instruction = Instruction::ShiftLeft(RTypeArgs::new(
         Some(Register::Rg0),

compiler/src/backend/dsa/codegen.rs

@@ -9,8 +9,8 @@ use crate::backend::dsa::registers::Register;
 use crate::{block, comment, dsa};
 
 use crate::model::{
-    BinaryOperator, Call, CompilerError, ConstExpr, Declaration, Dependency, Expression,
+    AssignmentOperator, BinaryOperator, Call, CompilerError, ConstExpr, Declaration,
-    Program, Statement, TypeId, UnaryOperator, Variable,
+    Dependency, Expression, Program, Statement, TypeId, UnaryOperator, Variable,
 };
 
 pub struct CodeGenerator {
@@ -271,12 +271,17 @@ impl CodeGenerator {
                 self.allocator.free_temp(ptr_reg);
             }
 
-            Statement::Assign { varname, value } => {
+            Statement::Assign {
+                varname,
+                value,
+                operator,
+            } => {
                 // Evaluate expression
                 let (result_reg, expr_code) =
                     self.generate_expression(value, true, func_body)?;
                 code.extend(expr_code);
 
+                if *operator == AssignmentOperator::Assign {
                     // Check if this is a global variable
                     if self.is_global(varname) {
                         // Store to global label
@@ -289,6 +294,83 @@ impl CodeGenerator {
 
                     // Free temporary register
                     self.allocator.free_temp(result_reg);
+
+                    return Ok(code);
+                }
+
+                // for more complex assignment cases we need an intermediate register.
+                let (temp_reg, temp_code) = self.allocator.alloc_temp()?;
+                code.extend(temp_code);
+
+                // fetch the value of the variable
+                let (var_reg, var_code) = if self.is_global(varname) {
+                    (temp_reg, vec![format!("\tldw {}, {}", varname, temp_reg)])
+                } else {
+                    self.allocator.load_var(varname)?
+                };
+                code.extend(var_code);
+
+                let assign_code = match operator {
+                    AssignmentOperator::Assign => {
+                        unreachable!("assignment was already checked earlier.")
+                    }
+                    AssignmentOperator::AddAssign => {
+                        format!("\tadd {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::SubAssign => {
+                        format!("\tsub {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::MulAssign => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "TODO: implement multiplication for assignment"
+                        )));
+                    }
+                    AssignmentOperator::DivAssign => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "TODO: write proper div function for DSA"
+                        )));
+                    }
+                    AssignmentOperator::ModAssign => {
+                        format!("\tmod {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::AndAssign => {
+                        format!("\tand {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::OrAssign => {
+                        format!("\tor {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::XorAssign => {
+                        format!("\txor {var_reg}, {result_reg}, {temp_reg}")
+                    }
+                    AssignmentOperator::LeftShiftAssign => {
+                        // this is only useful if we optimise out the register allocation
+                        // inside value. if let Expression::Number
+                        // { value, .. } = *value {     format!("\
+                        // tshl {var_reg}, {value}, {temp_reg}") }
+                        format!("\tshl {var_reg}, {result_reg}, 0, {temp_reg}")
+                    }
+                    AssignmentOperator::RightShiftAssign => {
+                        // this is only useful if we optimise out the register allocation
+                        // if let Expression::Number { value, .. } = *value {
+                        //     format!("\tshr {var_reg}, {value}, {temp_reg}")
+                        // }
+                        format!("\tshr {var_reg}, {result_reg}, 0, {temp_reg}")
+                    }
+                };
+                code.push(assign_code);
+
+                // Check if this is a global variable
+                if self.is_global(varname) {
+                    // Store to global label
+                    code.push(format!("\tstw {}, {}", temp_reg, varname));
+                } else {
+                    // Store result in local variable
+                    let store_code = self.allocator.store_var(varname, &temp_reg);
+                    code.extend(store_code);
+                }
+
+                self.allocator.free_temp(result_reg);
+                self.allocator.free_temp(temp_reg);
             }
 
             Statement::Return(expr) => {
@@ -414,16 +496,17 @@ impl CodeGenerator {
         let mut code = Vec::new();
 
         match expr {
-            Expression::StringLiteral(value) => {
+            Expression::Empty => Ok((Register::Null, code)),
+
+            Expression::Number { value, .. } => {
                 let (reg, alloc_code) = self.allocator.alloc_temp()?;
                 code.extend(alloc_code);
 
-                // write string into memory
+                // Load immediate value
-                let uuid = self.get_unique_label();
+                code.push(format!("\tlli {}, {}", value & 0xFFFF, reg));
-                func_body.insert(0, format!("db str_{uuid}: \"{value}\""));
+                if *value > 0xFFFF || *value < 0 {
-
+                    code.push(format!("\tlui {}, {}", (value >> 16) & 0xFFFF, reg));
-                // Load pointer to string
+                }
-                code.push(format!("\tlwi str_{uuid}, {reg}"));
 
                 Ok((reg, code))
             }
@@ -438,19 +521,22 @@ impl CodeGenerator {
                 Ok((reg, code))
             }
 
-            Expression::Number { value, .. } => {
+            Expression::StringLiteral(value) => {
                 let (reg, alloc_code) = self.allocator.alloc_temp()?;
                 code.extend(alloc_code);
 
-                // Load immediate value
+                // write string into memory
-                code.push(format!("\tlli {}, {}", value & 0xFFFF, reg));
+                let uuid = self.get_unique_label();
-                if *value > 0xFFFF || *value < 0 {
+                func_body.insert(0, format!("db str_{uuid}: \"{value}\""));
-                    code.push(format!("\tlui {}, {}", (value >> 16) & 0xFFFF, reg));
+
-                }
+                // Load pointer to string
+                code.push(format!("\tlwi str_{uuid}, {reg}"));
 
                 Ok((reg, code))
             }
 
+            Expression::ArrayLiteral { elements, type_id } => todo!(),
+
             Expression::Variable { name, .. } => {
                 if self.is_global(&name.name) {
                     // Allocate a temporary register for the global
@@ -489,16 +575,14 @@ impl CodeGenerator {
                 // Generate operation
                 match op {
                     BinaryOperator::Add => {
-                        code.push(format!(
+                        code.push(
-                            "\tadd {}, {}, {}",
+                            format!("\tadd {left_reg}, {right_reg}, {result_reg}",),
-                            left_reg, right_reg, result_reg
+                        );
-                        ));
                     }
                     BinaryOperator::Sub => {
-                        code.push(format!(
+                        code.push(
-                            "\tsub {}, {}, {}",
+                            format!("\tsub {left_reg}, {right_reg}, {result_reg}",),
-                            left_reg, right_reg, result_reg
+                        );
-                        ));
                     }
                     BinaryOperator::Mul => {
                         self.include("maths", "./lib/maths/core.dsa");
@@ -509,8 +593,55 @@ impl CodeGenerator {
                         code.push(format!("\tpop {}", result_reg));
                         code.push("\tpop zero".to_string());
                     }
+                    BinaryOperator::Div => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "TODO: write proper div function for DSA"
+                        )));
+                        // self.include("maths", "./lib/maths/core.dsa");
+                        // // Call divide function
+                        // code.push(format!("\tpush {}", right_reg));
+                        // code.push(format!("\tpush {}", left_reg));
+                        // code.push("\tcall maths::divide".to_string());
+                        // code.push(format!("\tpop {}", result_reg));
+                        // code.push("\tpop zero".to_string());
+                    }
+                    BinaryOperator::Mod => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "TODO: write proper mod function for DSA"
+                        )));
+                        // self.include("maths", "./lib/maths/core.dsa");
+                        // // Call modulo function
+                        // code.push(format!("\tpush {}", right_reg));
+                        // code.push(format!("\tpush {}", left_reg));
+                        // code.push("\tcall maths::modulo".to_string());
+                        // code.push(format!("\tpop {}", result_reg));
+                        // code.push("\tpop zero".to_string());
+                    }
+                    BinaryOperator::BitwiseAnd => {
+                        code.push(format!("\tand {left_reg}, {right_reg}, {result_reg}"));
+                    }
+                    BinaryOperator::BitwiseOr => {
+                        code.push(format!("\tor {left_reg}, {right_reg}, {result_reg}"));
+                    }
+                    BinaryOperator::BitwiseXor => {
+                        code.push(format!("\txor {left_reg}, {right_reg}, {result_reg}"));
+                    }
+                    BinaryOperator::LogicalAnd => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "assembler/ISA does not yet support logical and!"
+                        )));
+                    }
+                    BinaryOperator::LogicalOr => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "assembler/ISA does not yet support logical or!"
+                        )));
+                    }
+                    BinaryOperator::LeftShift => code
+                        .push(format!("\tshl {left_reg}, {right_reg}, 0, {result_reg}")),
+                    BinaryOperator::RightShift => code
+                        .push(format!("\tshr {left_reg}, {right_reg}, 0, {result_reg}")),
                     // Comparison operators - return 1 (true) or 0 (false)
-                    BinaryOperator::Eq => {
+                    BinaryOperator::Equal => {
                         code.push(format!("\tcmp {}, {}", left_reg, right_reg));
                         code.push(format!("\tlli 1, {}", result_reg));
                         let end_label = format!("_cmp_end_{}", self.get_unique_label());
@@ -518,7 +649,7 @@ impl CodeGenerator {
                         code.push(format!("\tlli 0, {}", result_reg));
                         code.push(format!("{}:", end_label));
                     }
-                    BinaryOperator::Ne => {
+                    BinaryOperator::NotEqual => {
                         code.push(format!("\tcmp {}, {}", left_reg, right_reg));
                         code.push(format!("\tlli 1, {}", result_reg));
                         let end_label = format!("_cmp_end_{}", self.get_unique_label());
@@ -526,7 +657,7 @@ impl CodeGenerator {
                         code.push(format!("\tlli 0, {}", result_reg));
                         code.push(format!("{}:", end_label));
                     }
-                    BinaryOperator::Lt => {
+                    BinaryOperator::LessThan => {
                         code.push(format!("\tcmp {}, {}", left_reg, right_reg));
                         code.push(format!("\tlli 1, {}", result_reg));
                         let end_label = format!("_cmp_end_{}", self.get_unique_label());
@@ -534,7 +665,7 @@ impl CodeGenerator {
                         code.push(format!("\tlli 0, {}", result_reg));
                         code.push(format!("{}:", end_label));
                     }
-                    BinaryOperator::Le => {
+                    BinaryOperator::LessOrEqual => {
                         code.push(format!("\tcmp {}, {}", left_reg, right_reg));
                         code.push(format!("\tlli 1, {}", result_reg));
                         let end_label = format!("_cmp_end_{}", self.get_unique_label());
@@ -542,7 +673,7 @@ impl CodeGenerator {
                         code.push(format!("\tlli 0, {}", result_reg));
                         code.push(format!("{}:", end_label));
                     }
-                    BinaryOperator::Gt => {
+                    BinaryOperator::GreaterThan => {
                         code.push(format!("\tcmp {}, {}", left_reg, right_reg));
                         code.push(format!("\tlli 1, {}", result_reg));
                         let end_label = format!("_cmp_end_{}", self.get_unique_label());
@@ -550,15 +681,14 @@ impl CodeGenerator {
                         code.push(format!("\tlli 0, {}", result_reg));
                         code.push(format!("{}:", end_label));
                     }
-                    BinaryOperator::Ge => {
+                    BinaryOperator::GreaterOrEqual => {
                         code.push(format!("\tcmp {}, {}", left_reg, right_reg));
                         code.push(format!("\tlli 1, {}", result_reg));
                         let end_label = format!("_cmp_end_{}", self.get_unique_label());
                         code.push(format!("\tjge {}", end_label));
                         code.push(format!("\tlli 8, {}", result_reg));
                         code.push(format!("{}:", end_label));
-                    }
+                    } // _ => unimplemented!(),
-                    _ => unimplemented!(),
                 }
 
                 // Free operand registers (allocator will protect variables)
@@ -568,6 +698,105 @@ impl CodeGenerator {
                 Ok((result_reg, code))
             }
 
+            Expression::UnaryPostfix { op, operand, .. } => {
+                let (operand_reg, operand_code) =
+                    self.generate_expression(operand, true, func_body)?;
+                code.extend(operand_code);
+
+                let (result_reg, result_alloc) = self.allocator.alloc_temp()?;
+                code.extend(result_alloc);
+
+                match op {
+                    UnaryOperator::Increment => {
+                        // prefix increment
+                        // code.push(format!("\taddi {}, 1, {}", operand_reg,
+                        // operand_reg));
+                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::Decrement => {
+                        // prefix decrement
+                        // code.push(format!("\tsubi {}, 1, {}", operand_reg,
+                        // operand_reg));
+                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                    }
+                    _ => {
+                        return Err(CompilerError::Generic(format!(
+                            "{op} is prefix only!"
+                        )));
+                    }
+                }
+
+                self.allocator.free_temp(operand_reg);
+                Ok((result_reg, code))
+            }
+
+            Expression::Unary { op, operand, .. } => {
+                let (operand_reg, operand_code) =
+                    self.generate_expression(operand, true, func_body)?;
+                code.extend(operand_code);
+
+                let (result_reg, result_alloc) = self.allocator.alloc_temp()?;
+                code.extend(result_alloc);
+
+                match op {
+                    UnaryOperator::Minus => {
+                        // Negate: result = 0 - operand
+                        code.push(format!("\tsub zero, {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::Plus => {
+                        // Just move
+                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::Dereference => {
+                        code.push(format!("\tldw {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::AddressOf => {
+                        // ensure the referenced variable is on the stack and return its
+                        // address.
+                        let (offset, alloc_code) =
+                            self.allocator.free_register(&operand_reg)?;
+                        code.extend(alloc_code);
+                        code.push(format!(
+                            "\taddi spr, {}, {}",
+                            offset - self.allocator.get_stack_offset(),
+                            result_reg
+                        ));
+                    }
+                    UnaryOperator::SizeOf => {
+                        if let Ok(id) = operand.type_id() {
+                            let size = id.size();
+                            code.push(format!("\tmov {}, {}", size, result_reg));
+                        }
+                    }
+                    UnaryOperator::Increment => {
+                        // prefix increment
+                        // code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                        code.push(format!("\taddi {}, 1, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::Decrement => {
+                        // prefix decrement
+                        // code.push(format!("\tmov {}, {}", operand_reg, result_reg));
+                        code.push(format!("\tsubi {}, 1, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::BitwiseNot => {
+                        code.push(format!("\tnot {}, {}", operand_reg, result_reg));
+                    }
+                    UnaryOperator::LogicalNot => {
+                        return Err(CompilerError::Unimplemented(format!(
+                            "Assembler/ISA does not yet support logical not"
+                        )));
+                    }
+                    _ => {
+                        return Err(CompilerError::Generic(format!(
+                            "{op} is postfix only!"
+                        )));
+                    }
+                }
+
+                self.allocator.free_temp(operand_reg);
+                Ok((result_reg, code))
+            }
+
             Expression::Call {
                 func: Call { name, args },
                 ..
@@ -581,13 +810,6 @@ impl CodeGenerator {
                     arg_regs.push(arg_reg);
                 }
 
-                // Save caller-saved registers and track which ones we saved
-                // old method, inefficient.
-                // let saved_regs = self.allocator.get_caller_saved_registers();
-                // for reg in &saved_regs {
-                //     code.push(format!("\tpush {}", reg));
-                // }
-
                 // Save caller-saved registers and track which ones we saved
                 let saved_regs = self.allocator.get_caller_saved_registers();
                 for reg in &saved_regs {
@@ -604,9 +826,6 @@ impl CodeGenerator {
                     ));
                 }
 
-                // if GLOBAL_METHODS.contains_key(name.name.as_str()) {
-                //     code.push(format!("\tcall {}",
-                // GLOBAL_METHODS[name.name.as_str()])); } else
                 if self.symbols.contains(&name.name) {
                     // Call local function
                     code.push(format!("\tcall {}", name));
@@ -644,11 +863,6 @@ impl CodeGenerator {
                     }
                 }
 
-                // Restore caller-saved registers in reverse order (LIFO)
-                // for reg in saved_regs.iter().rev() {
-                //     code.push(format!("\tpop {}", reg));
-                // }
-
                 // Free argument registers
                 for reg in arg_regs {
                     self.allocator.free_temp(reg);
@@ -657,43 +871,52 @@ impl CodeGenerator {
                 Ok((result_reg, code))
             }
 
-            Expression::Unary { op, operand, .. } => {
+            Expression::IndexAccess {
-                let (operand_reg, operand_code) =
+                expr,
-                    self.generate_expression(operand, true, func_body)?;
+                index,
-                code.extend(operand_code);
+                type_id,
+            } => {
+                let (expr_reg, expr_alloc) =
+                    self.generate_expression(expr, true, func_body)?;
+                code.extend(expr_alloc);
+
+                let (index_reg, index_alloc) =
+                    self.generate_expression(index, true, func_body)?;
+                code.extend(index_alloc);
 
                 let (result_reg, result_alloc) = self.allocator.alloc_temp()?;
                 code.extend(result_alloc);
 
-                match op {
+                // add the expr pointer to the index to get the final address.
-                    UnaryOperator::Minus => {
+                code.push(format!("\tadd {expr_reg} {index_reg} {result_reg}"));
-                        // Negate: result = 0 - operand
+                // load the value at the address.
-                        code.push(format!("\tsub zero, {}, {}", operand_reg, result_reg));
+                code.push(format!("\tldw {result_reg} {result_reg}"));
-                    }
+
-                    UnaryOperator::Plus => {
+                self.allocator.free_temp(expr_reg);
-                        // Just move
+                self.allocator.free_temp(index_reg);
-                        code.push(format!("\tmov {}, {}", operand_reg, result_reg));
-                    }
-                    UnaryOperator::Dereference => {
-                        code.push(format!("\tldw {}, {}", operand_reg, result_reg));
-                    }
-                    UnaryOperator::Reference => {
-                        let (offset, alloc_code) =
-                            self.allocator.free_register(&operand_reg)?;
-                        code.extend(alloc_code);
-                        code.push(format!(
-                            "\taddi spr, {}, {}",
-                            offset - self.allocator.get_stack_offset(),
-                            result_reg
-                        ));
-                    }
-                }
 
-                self.allocator.free_temp(operand_reg);
                 Ok((result_reg, code))
             }
+            Expression::MemberAccess {
+                expr,
+                field_name,
+                type_id,
+            } => Err(CompilerError::Unimplemented(format!(
+                "Structs are not yet implemented!"
+            ))),
 
-            Expression::Empty => Ok((Register::Null, code)),
+            Expression::TypeCast {
+                expr,
+                target_type,
+                type_id,
+            } => {
+                let (expr_reg, expr_code) =
+                    self.generate_expression(expr, true, func_body)?;
+
+                // not sure if we actually need to do anything here.
+                // for now we just return the previous expression.
+                Ok((expr_reg, expr_code))
+            }
         }
     }
 

compiler/src/backend/dsa/registers.rs

@@ -132,7 +132,7 @@ impl RegisterAllocator {
         }
 
         // This is a true temporary - safe to free
-        if reg != Register::Zero {
+        if !matches!(reg, Register::Zero | Register::Null) {
             self.in_use.insert(reg, false);
         }
     }
@@ -141,7 +141,7 @@ impl RegisterAllocator {
         // Check if this variable is in a register
         if let Some(location) = self.variable_locations.get(var).cloned() {
             if let Some(reg) = location.register
-                && reg != Register::Zero
+                && !matches!(reg, Register::Zero | Register::Null)
             {
                 self.register_contents.remove(&reg);
                 self.in_use.insert(reg, false);

compiler/src/frontend/dsc/parser.rs

@@ -1,7 +1,8 @@
 use super::lexer::Token;
 use crate::model::{
-    BinaryOperator, Block, Call, CompilerError, ConstExpr, Declaration, Dependency,
+    AssignmentOperator, BinaryOperator, Block, Call, CompilerError, ConstExpr,
-    Expression, Program, Statement, TypeId, UnaryOperator, Variable,
+    Declaration, Dependency, Expression, Program, Statement, TypeId, UnaryOperator,
+    Variable,
 };
 use crate::{expect_tt, expect_value};
 use std::ops::{ControlFlow, FromResidual, Try};
@@ -328,7 +329,26 @@ impl Parser {
             }
 
             self.next()?;
-            let _ = expect_tt!(self.next()?, Assign)?;
+            let operator = match self.peek_next()? {
+                Token::Assign => AssignmentOperator::Assign,
+                Token::PlusEqual => AssignmentOperator::AddAssign,
+                Token::MinusEqual => AssignmentOperator::SubAssign,
+                Token::StarEqual => AssignmentOperator::MulAssign,
+                Token::SlashEqual => AssignmentOperator::DivAssign,
+                Token::PercentEqual => AssignmentOperator::ModAssign,
+                Token::AndEqual => AssignmentOperator::AndAssign,
+                Token::OrEqual => AssignmentOperator::OrAssign,
+                Token::XorEqual => AssignmentOperator::XorAssign,
+                Token::ShlEqual => AssignmentOperator::LeftShiftAssign,
+                Token::ShrEqual => AssignmentOperator::RightShiftAssign,
+                _ => {
+                    return ParseResult::Reject(CompilerError::UnexpectedToken(
+                        self.peek_next()?.tt().to_string(),
+                    ));
+                }
+            };
+
+            self.next()?;
 
             let value = self.parse_expression()?;
 
@@ -336,6 +356,7 @@ impl Parser {
 
             return ParseResult::Accept(Statement::Assign {
                 varname: varname.name,
+                operator,
                 value,
             });
         }
@@ -346,32 +367,132 @@ impl Parser {
     }
 
     fn parse_expression(&mut self) -> ParseResult<Expression, CompilerError> {
-        self.parse_comparison()
+        self.parse_logical_or()
+    }
+
+    fn parse_logical_or(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_logical_and()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::LogicalOr,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_logical_or()?),
+            type_id: Some(TypeId::U32),
+        })
+    }
+
+    fn parse_logical_and(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_bitwise_or()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::LogicalAnd,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_logical_and()?),
+            type_id: Some(TypeId::U32),
+        })
+    }
+
+    fn parse_bitwise_or(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_bitwise_xor()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::BitwiseOr,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_bitwise_or()?),
+            type_id: Some(TypeId::U32),
+        })
+    }
+
+    fn parse_bitwise_xor(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_bitwise_and()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::BitwiseXor,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_bitwise_xor()?),
+            type_id: Some(TypeId::U32),
+        })
+    }
+
+    fn parse_bitwise_and(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_comparison()?;
+
+        let op = match self.peek_next()? {
+            Token::Ampersand => BinaryOperator::BitwiseAnd,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_bitwise_and()?),
+            type_id: Some(TypeId::U32),
+        })
     }
 
     fn parse_comparison(&mut self) -> ParseResult<Expression, CompilerError> {
-        let mut expr = self.parse_additive()?;
+        let left = self.parse_shift()?;
 
-        while let Some(op) = match self.peek_next()? {
+        let op = match self.peek_next()? {
-            Token::EqualEqual => Some(BinaryOperator::Eq),
+            Token::EqualEqual => BinaryOperator::Equal,
-            Token::BangEqual => Some(BinaryOperator::Ne),
+            Token::BangEqual => BinaryOperator::NotEqual,
-            Token::Less => Some(BinaryOperator::Lt),
+            Token::Less => BinaryOperator::LessThan,
-            Token::Greater => Some(BinaryOperator::Gt),
+            Token::Greater => BinaryOperator::GreaterThan,
-            Token::LessEqual => Some(BinaryOperator::Le),
+            Token::LessEqual => BinaryOperator::LessOrEqual,
-            Token::GreaterEqual => Some(BinaryOperator::Ge),
+            Token::GreaterEqual => BinaryOperator::GreaterOrEqual,
-            _ => None,
+            _ => return ParseResult::Accept(left),
-        } {
-            self.next()?;
-            let right = Box::new(self.parse_additive()?);
-            expr = Expression::Binary {
-                op,
-                left: Box::new(expr),
-                right,
-                type_id: Some(TypeId::Bool),
         };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_comparison()?),
+            type_id: Some(TypeId::Bool),
+        })
     }
 
-        ParseResult::Accept(expr)
+    fn parse_shift(&mut self) -> ParseResult<Expression, CompilerError> {
+        let left = self.parse_additive()?;
+
+        let op = match self.peek_next()? {
+            Token::LeftShift => BinaryOperator::LeftShift,
+            Token::RightShift => BinaryOperator::RightShift,
+            _ => return ParseResult::Accept(left),
+        };
+
+        self.next()?;
+        ParseResult::Accept(Expression::Binary {
+            op,
+            left: Box::new(left),
+            right: Box::new(self.parse_shift()?),
+            type_id: Some(TypeId::U32),
+        })
     }
 
     fn parse_additive(&mut self) -> ParseResult<Expression, CompilerError> {
@@ -412,11 +533,27 @@ impl Parser {
 
     fn parse_unary(&mut self) -> ParseResult<Expression, CompilerError> {
         let op = match self.peek_next()? {
+            // prefix inc/dec
+            Token::PlusPlus => UnaryOperator::Increment,
+            Token::MinusMinus => UnaryOperator::Decrement,
+
+            // arithmetic
             Token::Plus => UnaryOperator::Plus,
             Token::Minus => UnaryOperator::Minus,
+
+            // pointer
             Token::Star => UnaryOperator::Dereference,
-            Token::Amphersand => UnaryOperator::Reference,
+            Token::Ampersand => UnaryOperator::AddressOf,
-            _ => return ParseResult::Accept(self.parse_primary()?),
+
+            // boolean
+            Token::Bang => UnaryOperator::LogicalNot,
+            Token::Tilde => UnaryOperator::BitwiseNot,
+
+            Token::SizeOf => UnaryOperator::SizeOf,
+            _ => {
+                let expr = self.parse_primary()?;
+                return self.parse_postfix(expr);
+            }
         };
 
         self.next()?;
@@ -428,6 +565,99 @@ impl Parser {
         })
     }
 
+    fn parse_postfix(
+        &mut self,
+        mut expr: Expression,
+    ) -> ParseResult<Expression, CompilerError> {
+        loop {
+            match self.peek_next()? {
+                // Type cast: expr as Type
+                Token::As => {
+                    self.next()?; // consume 'as'
+                    let target_type = self.parse_type()?;
+                    expr = Expression::TypeCast {
+                        expr: Box::new(expr),
+                        target_type,
+                        type_id: None,
+                    };
+                }
+
+                // Postfix increment/decrement
+                Token::PlusPlus => {
+                    self.next()?;
+                    expr = Expression::UnaryPostfix {
+                        op: UnaryOperator::Increment,
+                        operand: Box::new(expr),
+                        type_id: None,
+                    };
+                }
+                Token::MinusMinus => {
+                    self.next()?;
+                    expr = Expression::UnaryPostfix {
+                        op: UnaryOperator::Decrement,
+                        operand: Box::new(expr),
+                        type_id: None,
+                    };
+                }
+
+                // Array indexing: expr[index]
+                Token::LeftBracket => {
+                    self.next()?; // consume '['
+                    let index = Box::new(self.parse_expression()?);
+
+                    let _ = expect_tt!(self.next()?, RightBracket)?;
+
+                    expr = Expression::IndexAccess {
+                        expr: Box::new(expr),
+                        index,
+                        type_id: None,
+                    };
+                }
+
+                // Function call: expr(args...)
+                Token::LeftParen => {
+                    self.next()?; // consume '('
+                    let mut args = Vec::new();
+
+                    if !matches!(self.peek_next()?, Token::RightParen) {
+                        loop {
+                            args.push(self.parse_expression()?);
+                            if !matches!(self.peek_next()?, Token::Comma) {
+                                break;
+                            }
+                            self.next()?; // consume comma
+                        }
+                    }
+
+                    let _ = expect_tt!(self.next()?, RightParen)?;
+
+                    if let Expression::Variable { name, .. } = expr {
+                        expr = Expression::Call {
+                            func: Call { name, args },
+                            type_id: None,
+                        };
+                    }
+                }
+
+                // Member access: expr.member (if you support structs)
+                Token::Dot => {
+                    self.next()?;
+                    let field_name = expect_value!(self.next()?, Identifier)?;
+                    expr = Expression::MemberAccess {
+                        expr: Box::new(expr),
+                        field_name,
+                        type_id: None,
+                    };
+                }
+
+                // No more postfix operations
+                _ => break,
+            }
+        }
+
+        ParseResult::Accept(expr)
+    }
+
     fn parse_primary(&mut self) -> ParseResult<Expression, CompilerError> {
         match self.peek_next()? {
             Token::Integer(value) => {
@@ -441,39 +671,37 @@ impl Parser {
                 self.next()?;
                 ParseResult::Accept(Expression::StringLiteral(value))
             }
-            Token::Identifier(_) => {
+            Token::Char(value) => {
-                let name = expect_value!(self.next()?, Identifier)?;
-
-                if matches!(self.peek_next()?, Token::LeftParen) {
-                    // Function call
                 self.next()?;
-                    let mut args = Vec::new();
+                ParseResult::Accept(Expression::CharLiteral(value))
-
-                    if !matches!(self.peek_next()?, Token::RightParen) {
-                        args.push(self.parse_expression()?);
-
-                        while matches!(self.peek_next()?, Token::Comma) {
-                            self.next()?;
-                            args.push(self.parse_expression()?);
-                        }
             }
 
-                    let _ = expect_tt!(self.next()?, RightParen)?;
+            Token::Identifier(name) => {
-
+                self.next()?;
-                    ParseResult::Accept(Expression::Call {
-                        func: Call {
-                            name: name.clone(),
-                            args,
-                        },
-
-                        type_id: None,
-                    })
-                } else {
                 ParseResult::Accept(Expression::Variable {
                     name,
                     expr_type: None,
                 })
             }
+            Token::LeftBracket => {
+                self.next()?; // consume '['
+                let mut elements = Vec::new();
+
+                if !matches!(self.peek_next()?, Token::RightBracket) {
+                    loop {
+                        elements.push(self.parse_expression()?);
+                        if !matches!(self.peek_next()?, Token::Comma) {
+                            break;
+                        }
+                        self.next()?; // consume comma
+                    }
+                }
+
+                expect_tt!(self.next()?, RightBracket)?;
+                ParseResult::Accept(Expression::ArrayLiteral {
+                    elements,
+                    type_id: None,
+                })
             }
             Token::LeftParen => {
                 self.next()?;

compiler/src/model.rs

@@ -11,6 +11,7 @@ pub enum CompilerError {
     Generic(String),
     UnknownType,
     TypeMismatch(TypeId, TypeId),
+    Unimplemented(String),
 }
 
 #[derive(Debug, PartialEq, Eq, Clone)]
@@ -65,6 +66,26 @@ pub enum TypeId {
     Struct { name: Name, fields: Vec<TypeId> },
 }
 
+impl TypeId {
+    pub fn size(&self) -> usize {
+        match self {
+            Self::U8 => 1,
+            Self::U16 => 2,
+            Self::U32 => 4,
+            Self::I8 => 1,
+            Self::I16 => 2,
+            Self::I32 => 4,
+            Self::Bool => 1,
+            Self::Char => 1,
+            Self::Void => 0,
+            Self::Ptr(t) => t.size(),
+            Self::Ref(t) => t.size(),
+            Self::Array(t, size) => t.size() * size,
+            Self::Struct { fields, .. } => fields.iter().map(|t| t.size()).sum(),
+        }
+    }
+}
+
 impl fmt::Display for TypeId {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
         match self {
@@ -110,6 +131,7 @@ pub enum Statement {
     },
     Assign {
         varname: String,
+        operator: AssignmentOperator,
         value: Expression,
     },
     PtrWrite {
@@ -169,10 +191,38 @@ pub enum Expression {
         // Post-Semantic Analysis
         type_id: Option<TypeId>,
     },
+    UnaryPostfix {
+        op: UnaryOperator,
+        operand: Box<Expression>,
+
+        // Post-Semantic Analysis
+        type_id: Option<TypeId>,
+    },
     Variable {
         name: Name,
         expr_type: Option<TypeId>,
     },
+    TypeCast {
+        expr: Box<Expression>,
+        target_type: TypeId,
+
+        // Post-Semantic Analysis
+        type_id: Option<TypeId>,
+    },
+    IndexAccess {
+        expr: Box<Expression>,
+        index: Box<Expression>,
+
+        // Post-Semantic Analysis
+        type_id: Option<TypeId>,
+    },
+    MemberAccess {
+        expr: Box<Expression>,
+        field_name: Name,
+
+        // Post-Semantic Analysis
+        type_id: Option<TypeId>,
+    },
     Call {
         func: Call,
 
@@ -187,6 +237,10 @@ pub enum Expression {
     },
     StringLiteral(String),
     CharLiteral(char),
+    ArrayLiteral {
+        elements: Vec<Expression>,
+        type_id: Option<TypeId>,
+    },
 }
 
 #[derive(Debug, Clone)]
@@ -204,8 +258,17 @@ impl Expression {
             Expression::Call { .. } => false,
             Expression::Binary { left, right, .. } => left.is_pure() && right.is_pure(),
             Expression::Unary { operand, .. } => operand.is_pure(),
+            Expression::UnaryPostfix { operand, .. } => operand.is_pure(),
             Expression::Empty => true,
             Expression::Variable { .. } => true,
+            Expression::TypeCast { expr, .. } => expr.is_pure(),
+            Expression::IndexAccess { expr, index, .. } => {
+                expr.is_pure() && index.is_pure()
+            }
+            Expression::MemberAccess { expr, .. } => expr.is_pure(),
+            Expression::ArrayLiteral { elements, type_id } => {
+                elements.iter().all(|element| element.is_pure())
+            }
         }
     }
 
@@ -225,42 +288,96 @@ impl Expression {
             Expression::Unary { type_id, .. } => {
                 type_id.clone().ok_or(CompilerError::UnknownType)
             }
+            Expression::UnaryPostfix { type_id, .. } => {
+                type_id.clone().ok_or(CompilerError::UnknownType)
+            }
             Expression::Empty => Ok(TypeId::Void),
             Expression::Variable { expr_type, .. } => {
                 expr_type.clone().ok_or(CompilerError::UnknownType)
             }
+            Expression::TypeCast { type_id, .. } => {
+                type_id.clone().ok_or(CompilerError::UnknownType)
+            }
+            Expression::IndexAccess { expr, .. } => expr.type_id(),
+            Expression::MemberAccess { expr, .. } => expr.type_id(),
+            Expression::ArrayLiteral { elements, .. } => {
+                let element_type = elements
+                    .first()
+                    .map_or(TypeId::Void, |e| e.type_id().unwrap_or(TypeId::Void));
+                Ok(TypeId::Array(Box::new(element_type), elements.len()))
             }
         }
     }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub enum AssignmentOperator {
+    Assign,
+    AddAssign,
+    SubAssign,
+    MulAssign,
+    DivAssign,
+    ModAssign,
+    AndAssign,
+    OrAssign,
+    XorAssign,
+    LeftShiftAssign,
+    RightShiftAssign,
+}
 
 #[allow(unused)]
 #[derive(Debug, Clone, PartialEq)]
 pub enum BinaryOperator {
+    // arithmetic
     Add,
     Sub,
     Mul,
     Div,
-    Eq,
+    Mod,
-    Ne,
+
-    Lt,
+    // comparison
-    Gt,
+    Equal,
-    Le,
+    NotEqual,
-    Ge,
+    LessThan,
+    GreaterThan,
+    LessOrEqual,
+    GreaterOrEqual,
+
+    // bitwise
+    BitwiseAnd,
+    BitwiseOr,
+    BitwiseXor,
+
+    // logical
+    LogicalAnd,
+    LogicalOr,
+
+    // shift
+    LeftShift,
+    RightShift,
 }
 
 impl fmt::Display for BinaryOperator {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            BinaryOperator::Add => write!(f, "+"),
+            Self::Add => write!(f, "+"),
-            BinaryOperator::Sub => write!(f, "-"),
+            Self::Sub => write!(f, "-"),
-            BinaryOperator::Mul => write!(f, "*"),
+            Self::Mul => write!(f, "*"),
-            BinaryOperator::Div => write!(f, "/"),
+            Self::Div => write!(f, "/"),
-            BinaryOperator::Eq => write!(f, "=="),
+            Self::Mod => write!(f, "%"),
-            BinaryOperator::Ne => write!(f, "!="),
+            Self::Equal => write!(f, "=="),
-            BinaryOperator::Lt => write!(f, "<"),
+            Self::NotEqual => write!(f, "!="),
-            BinaryOperator::Gt => write!(f, ">"),
+            Self::LessThan => write!(f, "<"),
-            BinaryOperator::Le => write!(f, "<="),
+            Self::GreaterThan => write!(f, ">"),
-            BinaryOperator::Ge => write!(f, ">="),
+            Self::LessOrEqual => write!(f, "<="),
+            Self::GreaterOrEqual => write!(f, ">="),
+            Self::BitwiseAnd => write!(f, "&"),
+            Self::BitwiseOr => write!(f, "|"),
+            Self::BitwiseXor => write!(f, "^"),
+            Self::LogicalAnd => write!(f, "&&"),
+            Self::LogicalOr => write!(f, "||"),
+            Self::LeftShift => write!(f, "<<"),
+            Self::RightShift => write!(f, ">>"),
         }
     }
 }
@@ -269,17 +386,27 @@ impl fmt::Display for BinaryOperator {
 pub enum UnaryOperator {
     Plus,
     Minus,
-    Reference,
+    AddressOf,
     Dereference,
+    BitwiseNot,
+    LogicalNot,
+    Increment,
+    Decrement,
+    SizeOf,
 }
 
 impl fmt::Display for UnaryOperator {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            UnaryOperator::Plus => write!(f, "+"),
+            Self::Increment => write!(f, "++"),
-            UnaryOperator::Minus => write!(f, "-"),
+            Self::Decrement => write!(f, "--"),
-            UnaryOperator::Dereference => write!(f, "*"),
+            Self::Plus => write!(f, "+"),
-            UnaryOperator::Reference => write!(f, "&"),
+            Self::Minus => write!(f, "-"),
+            Self::Dereference => write!(f, "*"),
+            Self::AddressOf => write!(f, "&"),
+            Self::BitwiseNot => write!(f, "~"),
+            Self::LogicalNot => write!(f, "!"),
+            Self::SizeOf => write!(f, "sizeof"),
         }
     }
 }

emulator/src/emulator/system/model.rs

@@ -286,7 +286,7 @@ impl RegFile {
             Register::Sts => &mut self.sts,
             Register::Cir => &mut self.cir,
             Register::Pcx => &mut self.pcx,
-            _ => return Err(ProcessorError::InvalidRegister(Register::NoReg as u8)),
+            _ => return Err(ProcessorError::InvalidRegister(Register::Null as u8)),
         })
     }
 
@@ -321,7 +321,7 @@ impl RegFile {
             Register::Cir => self.cir,
             Register::Pcx => self.pcx,
             Register::Zero => 0,
-            _ => return Err(ProcessorError::InvalidRegister(Register::NoReg as u8)),
+            _ => return Err(ProcessorError::InvalidRegister(Register::Null as u8)),
         })
     }
 }

emulator/src/emulator/system/processor/mod.rs

@@ -349,17 +349,13 @@ impl Executable for Instruction {
             // Left shifts the value in Reg by the given amount (either a register, or a
             // literal value)
             Self::ShiftLeft(a) => {
-                let reg = cpu.get(a.sr1)?;
+                *cpu.reg(a.dr)? = shl(cpu.get(a.sr1)?, a.shamt + cpu.get(a.sr2)? as u8);
-                let val = a.shamt;
-                *cpu.reg(a.sr1)? = shl(reg, val);
             }
 
             // Right shifts the value in Reg by the given amount (either a register, or a
             // literal value).
             Self::ShiftRight(a) => {
-                let regval = cpu.get(a.sr1)?;
+                *cpu.reg(a.dr)? = shr(cpu.get(a.sr1)?, a.shamt + cpu.get(a.sr2)? as u8);
-                let val = a.shamt;
-                *cpu.reg(a.sr1)? = shr(regval, val);
             }
 
             // Adds the value of Src2 to Src1 and writes the result to a.dr