Add more code

Add some funcitons to work with variables, add more instructions and add
ability to stop the code from `ccl_instruction`

1 files changed, 12 insertions, 0 deletions

diff --git a/src/instruction/subtract.c b/src/instruction/subtract.c
new file mode 100644
index 0000000..f140cfb
--- /dev/null
+++ b/src/instruction/subtract.c
@@ -0,0 +1,12 @@
+#include "3cl.h"
+
+#include "stack.h"
+#include "utils.h"
+
+struct CCLFrame *ccl_instruction_subtract(struct CCL *ccl, struct CCLFrame *frame)
+{
+    if (ccl->stack.cur < 2)
+        die(1, "stack size is %d (%d required)", ccl->stack.cur, 2);
+    ccl_stack_push(&ccl->stack, -ccl_stack_pop(&ccl->stack) + ccl_stack_pop(&ccl->stack));
+    return frame;
+}