feat: emit idiv

2 files changed, 52 insertions, 1 deletions

diff --git a/src/codegen/nasm.c b/src/codegen/nasm.c
index 7f70cb6..50db1bc 100644
--- a/src/codegen/nasm.c
+++ b/src/codegen/nasm.c
@@ -92,10 +92,38 @@ static bool emit_operand(struct Emitter* emitter, struct Expr* expr)
 	return false;
 }
 
+static void emit_divide(struct Emitter* emitter, struct AssignStatement* assign)
+{
+	struct Token target = resolve_token(emitter, assign->target);
+	bool target_is_rax = target.length == 3 && memcmp(target.start, "rax", 3) == 0;
+	if (assign->target_deref || !target_is_rax)
+	{
+		fprintf(emitter->out, "\t; TODO: unsupported division\n");
+		return;
+	}
+
+	fprintf(emitter->out, "\tcqo\n");
+	fprintf(emitter->out, "\tidiv ");
+	emit_operand(emitter, assign->value);
+	fprintf(emitter->out, "\n");
+}
+
 static void emit_assign(struct Emitter* emitter, struct AssignStatement* assign)
 {
+	if (assign->value->kind == EXPR_BINARY)
+	{
+		fprintf(emitter->out, "\t; TODO: unsupported assignment\n");
+		return;
+	}
+
+	if (assign->op.type == TOKEN_SLASH_EQUAL)
+	{
+		emit_divide(emitter, assign);
+		return;
+	}
+
 	const char* mnemonic = assign_mnemonic(assign->op.type);
-	if (mnemonic == NULL || assign->value->kind == EXPR_BINARY)
+	if (mnemonic == NULL)
 	{
 		fprintf(emitter->out, "\t; TODO: unsupported assignment\n");
 		return;
diff --git a/tests/codegen_test.c b/tests/codegen_test.c
index 5b00203..e59e834 100644
--- a/tests/codegen_test.c
+++ b/tests/codegen_test.c
@@ -130,6 +130,28 @@ static void test_generate_param_substitution(struct TestContext* context)
 	free_program(&program);
 }
 
+static void test_generate_divide(struct TestContext* context)
+{
+	struct Lexer lexer = create_lexer("proc main\n{\nrax /= rbx\n}\n");
+	struct Program program;
+	check(context, parse_program(&lexer, &program));
+
+	FILE* out = tmpfile();
+	generate_nasm(&program, out);
+	fflush(out);
+	rewind(out);
+
+	char buffer[1024];
+	size_t read = fread(buffer, 1, sizeof(buffer) - 1, out);
+	buffer[read] = '\0';
+	fclose(out);
+
+	check(context, strstr(buffer, "cqo") != NULL);
+	check(context, strstr(buffer, "idiv rbx") != NULL);
+
+	free_program(&program);
+}
+
 void run_codegen_tests(struct TestContext* context)
 {
 	test_generate_consts_and_data(context);
@@ -137,4 +159,5 @@ void run_codegen_tests(struct TestContext* context)
 	test_generate_if(context);
 	test_generate_call(context);
 	test_generate_param_substitution(context);
+	test_generate_divide(context);
 }