diff --git a/csim.c b/csim.c
index 9ac1d73..b57e0de 100644
--- a/csim.c
+++ b/csim.c
@@ -1,31 +1,50 @@
+/**
+   @file csim.c
+   @author Adam Goldsmith
+   @author Jacob Komissar
+   @date 2016-04-25, 2016-04-26, 2016-04-27
+   
+@TODO ADD CORRECT NAME COMMENT AT TOP OF FILE
+   
+Exit statuses:
+ 0 - success
+ 1 - usage error
+-1 - file error
+
+ */
+/* Headers */
 #include <stdlib.h>
 #include <stdio.h>
 #include <getopt.h>
-#include <stdint.h>
 #include "cachelab.h"
 
-#define mprintf(...) if (VERBOSE) printf(__VA_ARGS__)
-
-void print_usage();
-size_t parse_int_arg(char *arg, char opt);
-
-/**
-   If VERBOSE is non-zero, mprintf will not print. Otherwise, it will.
-   Set in main().
- */
-int8_t VERBOSE = 0;
-
-/* USURE. As defined in conference. */
+/* Typedefs and structs */
+typedef unsigned char uint8_t;
+/* UNSURE. As defined in conference. */
 struct line_s {
-	int8_t validity;
+	uint8_t validity;
 	int tag;
 };
 typedef struct line_s line;
 
+/* Macros */
+#define mprintf(...) if (VERBOSE) printf(__VA_ARGS__)
+
+/* Prototypes */
+void print_usage(void);
+void bad_usage_error(void);
+size_t parse_int_arg(char *arg, char opt);
+size_t bits_to_size(uint8_t bits);
+
+/* Global variables */
+uint8_t VERBOSE = 0; // If nonzero, mprintf will not print. Set in main() if -v flag is given.
+
+
 
 int main(int argc, char* argv[])
 {
-	size_t set_index_bits = 0, lines = 0, block_bits = 0; // Useful variables.
+	uint8_t set_index_bits = 0, block_bits = 0; // Not-useful input variables.
+	size_t set_indices = 0, lines = 0, block_size = 0; //Useful variables
 	char *filename = NULL;
 	int opt = 0;
 	while ((opt=getopt(argc, argv, "hvs:E:b:t:")) != -1) {