From 3eb04547355c49b986e884e028652ac50762089b Mon Sep 17 00:00:00 2001
From: Yuchen Pei <hi@ypei.me>
Date: Sun, 30 Jan 2022 17:16:36 +1100
Subject: minor edits

---
 Assembler.hs       | 3 +++
 JackCompiler.hs    | 3 ++-
 jackos/Memory.jack | 2 +-
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/Assembler.hs b/Assembler.hs
index ca79a48..47959ea 100644
--- a/Assembler.hs
+++ b/Assembler.hs
@@ -80,12 +80,15 @@ stripJunk xs = filter (not . null) $ (filter (not . (flip elem " \t")) . head .
 stripLabels :: [[Char]] -> [[Char]]
 stripLabels = filter (not . (elem '('))
 
+-- For labels
 addLabels :: [[Char]] -> Int -> Map [Char] [Char] -> Map [Char] [Char]
 addLabels [] _ table = table
 addLabels ((hd:tl):rest) addr table
   | hd == '(' = addLabels rest addr (Map.insert (init tl) (int2Bin16 addr) table)
   | otherwise = addLabels rest (addr + 1) table
 
+-- For variables, addr is the current instruction address, vaddr is the
+-- variable memory address (to be assigned)
 addSyms :: [[Char]] -> Int -> Int -> Map [Char] [Char] -> Map [Char] [Char]
 addSyms [] _ _ table = table
 addSyms ((hd:tl):rest) addr vaddr table
diff --git a/JackCompiler.hs b/JackCompiler.hs
index f651f62..d0c375b 100644
--- a/JackCompiler.hs
+++ b/JackCompiler.hs
@@ -1,4 +1,5 @@
--- Jack Compiler, as the coursework of Project 11 of Nand2Tetris course (http://nand2tetris.org/).
+-- Jack Compiler, as the coursework of Project 11 of Nand2Tetris
+-- course (http://nand2tetris.org/).
 -- Author: Yuchen Pei (me@ypei.me)
 -- Date: 2018-01-15
 {-# LANGUAGE FlexibleContexts #-}
diff --git a/jackos/Memory.jack b/jackos/Memory.jack
index 54e04aa..82c10dd 100644
--- a/jackos/Memory.jack
+++ b/jackos/Memory.jack
@@ -53,7 +53,7 @@ class Memory {
             let heap[current + 1] = heap[current + 1] - size2;
             let newLast = current + heap[current + 1] + 2;
             let heap[newLast] = heap[current];
-            let heap[current] = newLast;
+            let heap[current] = newLast;  // This seems to be wrong - a free segment pointing to an allocated segment - will cause double allocation.
             let heap[newLast + 1] = size;
             return heap + newLast + 2;
         }
-- 
cgit v1.2.3