From df5418432e5f13632f8d464c9ee57fe663e0274d Mon Sep 17 00:00:00 2001
From: Aearnus <tslimkemann42@gmail.com>
Date: Thu, 24 May 2018 01:56:12 -0700
Subject: [PATCH] Define and call are done

---
 src/SixtyFiveOhTwo/Instruction.hs | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/SixtyFiveOhTwo/Instruction.hs b/src/SixtyFiveOhTwo/Instruction.hs
index 9ed6a89..6132a89 100644
--- a/src/SixtyFiveOhTwo/Instruction.hs
+++ b/src/SixtyFiveOhTwo/Instruction.hs
@@ -72,6 +72,8 @@ genericTwoByteOp op arg = do
     insState <- get
     return $ appendBytesThenWord [op] arg insState
 
+-- This allows you to define functions which can be called later using `call`.
+-- Note: your function must end with an `rts`, I don't add that automatically
 define :: String -> Instruction -> Instruction
 define name definition = do
     insState <- get
@@ -79,6 +81,13 @@ define name definition = do
     -- TODO: COMBINE THE FUNCTION DEFINITIONS HERE TOO NOT JUST BYTESTRINGS
     return $ execState definition insState'
 
+call :: String -> Instruction
+call name = do
+    insState <- get
+    let pointer = case (M.lookup name (insState ^. functionTable)) of
+                    Just ptr -> ptr
+                    Nothing -> error ("Couldn't find function " ++ name ++ ". Perhaps it wasn't `define`d?")
+    jsr (Absolute $ fromIntegral pointer)
 
 -- THE FOLLOWING WAS GENERATED BY
 -- https://github.com/aearnus/assemblicom