diff --git a/lang/codegen/expr.c b/lang/codegen/expr.c
index 53a2ec9..a5be549 100644
--- a/lang/codegen/expr.c
+++ b/lang/codegen/expr.c
@@ -223,12 +223,9 @@ static struct code_generator_result gen_var_reference(
 	struct mie_value *var_ptr = NULL;
 
 	struct ivy_ast_ident_node *ident = (struct ivy_ast_ident_node *)node;
-	struct codegen_var var = {};
+	struct codegen_var var = {.v_node = node};
 	enum ivy_status status
 		= codegen_resolve_variable(gen, ident->n_content->t_str, &var);
-	if (status != IVY_OK) {
-		return CODEGEN_RESULT_ERR(status);
-	}
 
 #if 0
 	if (var) {
@@ -391,16 +388,143 @@ static enum ivy_status state_init(
 	uintptr_t argv, void *argp)
 {
 	debug_printf("codegen: start of expression\n");
+	struct expr_codegen_state *expr = (struct expr_codegen_state *)state;
+
 	return IVY_OK;
 }
 
+static enum ivy_status gen_assignment(
+	struct ivy_codegen *gen, struct expr_codegen_state *expr,
+	struct ivy_ast_op_node *op, struct expr_item *left,
+	struct expr_item *right, struct mie_value **result)
+{
+	struct mie_value *left_value = left->i_value;
+	struct mie_value *right_value = right->i_value;
+
+	if (left->i_operand_type != EXPR_OPERAND_VAR) {
+		return IVY_ERR_BAD_SYNTAX;
+	}
+
+	if (right->i_operand_type == EXPR_OPERAND_VAR) {
+		right_value = codegen_load_variable(gen, &right->i_var);
+	} else {
+		right_value = right->i_value;
+	}
+
+	if (!left->i_var.v_type) {
+		struct mie_type *id_type
+			= mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
+		struct ivy_ast_ident_node *ident
+			= (struct ivy_ast_ident_node *)left->i_node;
+		const char *ident_str = ident->n_content->t_str;
+
+		struct mie_value *var_ptr
+			= mie_builder_alloca(gen->c_builder, id_type, ident_str);
+		struct codegen_var var_info = {
+			.v_node = (struct ivy_ast_node *)ident,
+			.v_type = id_type,
+			.v_flags = CODEGEN_VAR_F_PTR,
+			.v_value = var_ptr,
+		};
+
+		codegen_define_variable(gen, ident_str, &var_info);
+
+		memcpy(&left->i_var, &var_info, sizeof var_info);
+	}
+
+	codegen_store_variable(gen, &left->i_var, right_value);
+	*result = right_value;
+
+	return IVY_OK;
+}
+
+static enum ivy_status gen_op_assignment(
+	struct ivy_codegen *gen, struct expr_codegen_state *expr,
+	struct ivy_ast_op_node *op, struct expr_item *left,
+	struct expr_item *right, struct mie_value **result)
+{
+	struct mie_value *op_value = NULL;
+
+	if (left->i_operand_type != EXPR_OPERAND_VAR) {
+		return IVY_ERR_BAD_SYNTAX;
+	}
+
+	if (!left->i_var.v_type) {
+		return IVY_ERR_BAD_SYNTAX;
+	}
+
+	struct mie_value *left_var = left->i_value;
+	struct mie_value *left_value = codegen_load_variable(gen, &left->i_var);
+
+	struct mie_value *right_value = right->i_value;
+	if (right->i_operand_type == EXPR_OPERAND_VAR) {
+		right_value = codegen_load_variable(gen, &right->i_var);
+	}
+
+	switch (op->n_op->op_id) {
+	case IVY_OP_ADD_ASSIGN:
+		op_value = mie_builder_add(
+			gen->c_builder, left_value, right_value, "addtmp");
+		break;
+	case IVY_OP_SUBTRACT_ASSIGN:
+		op_value = mie_builder_sub(
+			gen->c_builder, left_value, right_value, "subtmp");
+		break;
+	case IVY_OP_MULTIPLY_ASSIGN:
+		op_value = mie_builder_mul(
+			gen->c_builder, left_value, right_value, "multmp");
+		break;
+	case IVY_OP_DIVIDE_ASSIGN:
+		op_value = mie_builder_div(
+			gen->c_builder, left_value, right_value, "divtmp");
+		break;
+	default:
+		return IVY_ERR_NOT_SUPPORTED;
+	}
+
+	codegen_store_variable(gen, &left->i_var, op_value);
+	*result = op_value;
+
+	return IVY_OK;
+}
+
+static struct mie_value *load_variable(
+	struct ivy_codegen *gen, struct codegen_var *var)
+{
+	struct ivy_ast_ident_node *ident = (struct ivy_ast_ident_node *)var->v_node;
+	struct mie_value *var_ptr = NULL;
+
+	if (var->v_value) {
+		/* this is a local variable */
+		var_ptr = var->v_value;
+	} else {
+		/* this is a global variable, and needs to be loaded via a data ptr */
+		var_ptr = mie_builder_get_data_ptr(
+			gen->c_builder, ident->n_content->t_str);
+	}
+
+	struct mie_type *id = mie_ctx_get_type(gen->c_ctx, MIE_TYPE_ID);
+	struct mie_value *var_value
+		= mie_builder_load(gen->c_builder, id, var_ptr, NULL);
+
+	return var_value;
+}
+
 static enum ivy_status state_fini(
 	struct ivy_codegen *gen, struct code_generator_state *state,
 	struct code_generator_value *result)
 {
+#define OP_IS_ASSIGNMENT(id)                                                      \
+	((id) == IVY_OP_ASSIGN || (id) == IVY_OP_ADD_ASSIGN                       \
+	 || (id) == IVY_OP_SUBTRACT_ASSIGN || (id) == IVY_OP_MULTIPLY_ASSIGN      \
+	 || (id) == IVY_OP_DIVIDE_ASSIGN || (id) == IVY_OP_MODULO_ASSIGN          \
+	 || (id) == IVY_OP_LEFT_SHIFT_ASSIGN || (id) == IVY_OP_RIGHT_SHIFT_ASSIGN \
+	 || (id) == IVY_OP_BINARY_AND_ASSIGN || (id) == IVY_OP_BINARY_OR_ASSIGN   \
+	 || (id) == IVY_OP_BINARY_XOR_ASSIGN)
 	debug_printf("codegen: end of expression\n");
 
 	struct expr_codegen_state *expr = (struct expr_codegen_state *)state;
+	enum ivy_status status = IVY_OK;
 	b_queue stack = B_QUEUE_INIT;
 
 	b_queue_entry *cur = NULL;
@@ -422,16 +546,47 @@ static enum ivy_status state_fini(
 
 		struct mie_value *left_value = left->i_value;
 		struct mie_value *right_value = right->i_value;
+		struct mie_value *op_value = NULL;
+
+		if (op->n_op->op_id == IVY_OP_ASSIGN) {
+			status = gen_assignment(
+				gen, expr, op, left, right, &op_value);
+			if (status != IVY_OK) {
+				break;
+			}
+
+			free(left);
+			goto skip_op;
+		}
+
+		if (OP_IS_ASSIGNMENT(op->n_op->op_id)) {
+			status = gen_op_assignment(
+				gen, expr, op, left, right, &op_value);
+			if (status != IVY_OK) {
+				break;
+			}
+
+			free(left);
+			goto skip_op;
+		}
 
 		if (left->i_operand_type == EXPR_OPERAND_VAR) {
-			left_value = codegen_load_variable(gen, &left->i_var);
+			left_value = load_variable(gen, &left->i_var);
+
+			if (!left_value) {
+				/* cannot resolve variable */
+				return IVY_ERR_BAD_SYNTAX;
+			}
 		}
 
 		if (right->i_operand_type == EXPR_OPERAND_VAR) {
-			right_value = codegen_load_variable(gen, &right->i_var);
-		}
+			right_value = load_variable(gen, &right->i_var);
 
-		struct mie_value *op_value = NULL;
+			if (!right_value) {
+				/* cannot resolve variable */
+				return IVY_ERR_BAD_SYNTAX;
+			}
+		}
 
 		switch (op->n_op->op_id) {
 		case IVY_OP_ADD:
@@ -495,10 +650,15 @@ static enum ivy_status state_fini(
 		free(left);
 		free(right);
 
+	skip_op:
 		item->i_value = op_value;
 		b_queue_push_back(&stack, &item->i_entry);
 	}
 
+	if (status != IVY_OK) {
+		return status;
+	}
+
 	cur = b_queue_pop_back(&stack);
 	if (!cur) {
 		return IVY_ERR_INTERNAL_FAILURE;
@@ -526,7 +686,8 @@ static struct code_generator_result value_received(
 	struct expr_codegen_state *expr = (struct expr_codegen_state *)state;
 
 	debug_printf("codegen: got sub-expr\n");
-	enum ivy_status status = push_operand(expr, NULL, value, NULL);
+	enum ivy_status status
+		= push_operand(expr, NULL, value->v_value.mie_value, NULL);
 	if (status != IVY_OK) {
 		return CODEGEN_RESULT_ERR(status);
 	}