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/* asgoldsmith-jikomissar */
/**
@file csim.c
@author Adam Goldsmith
@author Jacob Komissar
@date 2016-04-25, 2016-04-26, 2016-04-27, 2016-04-28
Cachelab: csim.c
Simulates a cache with arbitrary sets, associativity, and block size.
Reads from a valgrind trace, and outputs the number of hits, misses, and evictions.
With the verbose option (-v), outputs details for each operation.
Exit statuses:
0 - success
1 - usage error
-1 - file error
2 - memory error
*/
/**** Headers ****/
#include <stdlib.h>
#include <stdio.h>
#include <getopt.h>
#include "cachelab.h"
/******** Typedefs and structs ********/
typedef unsigned char uint8_t;
typedef struct {
int hits;
int misses;
int evictions;
} results;
/* Linked Line and related prototypes */
typedef struct linked_line_s linked_line;
struct linked_line_s {
uint8_t validity;
long tag;
linked_line* newer;
linked_line* older;
};
/******** Macros ********/
#define mprintf(...) if (VERBOSE) printf(__VA_ARGS__)
/******** Global variables ********/
static uint8_t VERBOSE = 0; /**< If nonzero, mprintf will not print. Set in main() if -v flag is given. */
/******** General Prototypes ********/
/* Option-parsing functions */
void print_usage(void);
void bad_usage_error(void);
long parse_int_arg(char *arg, char opt);
long bits_to_size(int bits);
/* Sub-main functions */
void increment_result_counters(char result, results* score);
/* Cache creation/deletion functions */
linked_line** make_cache(long num_sets, long num_lines);
linked_line* make_set(linked_line* newer, long num_lines);
void free_cache(linked_line** cache, long num_sets);
void free_set(linked_line* line);
/* Cache-viewing functions */
void print_cache(linked_line** cache, long num_sets);
void print_set(linked_line* line);
/* Cache access functions */
char cache_access(linked_line** cache, long address, int set_bits, int block_offset_bits, long num_lines);
linked_line* find_line(linked_line* set_head, long tag);
linked_line* update_set(linked_line* old_head, linked_line* new_head);
//linked_line* move_to_head(linked_line* new_head, linked_line* old_head);
/** MAIN **/
int main(int argc, char* argv[])
{
results score;
char buffer[20];
int set_index_bits = 0, block_offset_bits = 0; // Not-useful input variables.
long num_sets = 0, num_lines = 0, block_size = 0; //Useful variables
char *filename = NULL;
int opt = 0;
score.hits = 0;
score.misses = 0;
score.evictions = 0;
while ((opt=getopt(argc, argv, "hvs:E:b:t:")) != -1) {
switch (opt) {
/* TODO: maybe add checking for optarg swallowing actual arguments. */
case 'v':
VERBOSE = 1;
break;
case 's': // 2^s = number of sets
set_index_bits = (int)parse_int_arg(optarg, 's');
num_sets = bits_to_size(set_index_bits);
break;
case 'E': // associativity - lines per set
num_lines = parse_int_arg(optarg, 'E');
break;
case 'b': // 2^b = block size
block_offset_bits = (int)parse_int_arg(optarg, 'b');
block_size = bits_to_size(block_offset_bits);
break;
case 't':
filename = optarg;
break;
case 'h':
print_usage();
return 0;
default:
bad_usage_error();
}
}
/* If any required arguments were not provided. (argflags != 0b1111) */
if (!num_sets || !num_lines || !block_size || !filename) {
bad_usage_error();
}
/* End of argument parsing. */
linked_line** cache = make_cache(num_sets, num_lines);
/* FILE READING */
FILE* f = fopen(filename, "r");
if(!f) {
printf("Invalid file name: %s", filename);
exit(-1);
}
//char buffer[20];
while (fgets(buffer, 20, f)) {
if (buffer[0] == 'I') {
continue;
}
char* end;
char op = buffer[1];
long address = strtol(buffer+3, &end, 16);
long size = strtol(end+1, NULL, 16);
if (*end != ',' || !(op == 'S' || op == 'L' || op == 'M')) {
printf("Invalid input file, last line:\n%s\n", buffer);
return -1;
}
/* if(VERBOSE) */
/* print_cache(cache, num_sets); */
mprintf(" %c %lx,%lx", op, address, size);
char r = cache_access(cache, address, set_index_bits, block_offset_bits, num_lines);
increment_result_counters(r, &score);
if (op == 'M') { //Access again if modifying
r = cache_access(cache, address, set_index_bits, block_offset_bits, num_lines);
increment_result_counters(r, &score);
}
mprintf("\n");
}
printSummary(score.hits, score.misses, score.evictions);
fclose(f);
free_cache(cache, set_index_bits);
return 0;
}
/************************** OPTION-PARSING FUNCTIONS **************************/
void print_usage(void)
{
printf("Usage: ./csim [-hv] -s <number> -E <number> -b <number> -t <file>\n"
"Options:\n"
" -h Print this help.\n"
" -v Display trace info.\n"
" -s <number> The number of set index bits. Must be a positive integer.\n"
" -E <number> Associativity (lines per set). Must be a positive integer.\n"
" -b <number> The number of block bits. Must be a positive integer.\n"
" -t <file> Name of the file to read a valgrind trace from.");
}
/**
Prints the summarized usage and exits with status 1.
*/
void bad_usage_error(void)
{
printf("Usage: ./csim [-hv] -s <number> -E <number> -b <number> -t <file>\n");
exit(1);
}
/**
Parses a string into a an positive integer; error if not possible.
@param arg The string to parse.
@param opt The option being parsed. If 'E', the output can not be 0.
Otherwise, used only for helpful error messages.
@return The parsed long integer if the argument was valid .
@note Exits if argument is invalid.
*/
long parse_int_arg(char* arg, char opt)
{
char* end;
long i = strtol(arg, &end, 0);
if (*end != '\0') { // associativity can not be zero
printf("Invalid argument \"%s\" for option -%c\n", arg, opt);
bad_usage_error();
}
else if (i < 0) {
printf("Argument %s for option -%c too small (must be greater than 0)", arg, opt);
exit(1);
}
else if (opt == 'E') {
long long_max = (~0UL)>>1;
if (i==0) {
printf("Argument for option -E can not be 0\n");
exit(1);
}
else if (i == long_max) {
printf("Argument %s for option -E too large (must be less than %ld)\n", arg, long_max);
exit(1);
}
}
return i;
}
/**
Calculates a size using a given number of bits.
@param bits The power of 2 to use.
@return 2^bits if it does not overflow.
@note Exits if number of bits is larger than a signed int.
*/
long bits_to_size(int bits)
{
int max_shift = 8*sizeof(int)-1;
if (bits > max_shift-1) {
printf("Argument %d too large (-s and -b must be less than %d)", bits, max_shift);
exit(1);
}
return (long)1 << bits;
}
/***************************** SUB-MAIN FUNCTIONS *****************************/
/**
Increments the cgiven ache operation counters based on the given result code.
@param result The cache operation result code to parse (H, M, or E).
@param score The score struct to increment.
@TODO Fix this into a total of 3 conditionals.
*/
void increment_result_counters(char result, results* score)
{
if (result == 'H') {
score->hits++;
mprintf(" hit");
}
else if (result == 'M') {
score->misses++;
mprintf(" miss");
}
else if (result == 'E') {
score->misses++;
score->evictions++;
mprintf(" miss eviction");
}
}
/********************* CACHE CREATION/DELETION FUNCTIONS *********************/
/**
@param num_sets The number of sets in the cache.
@param num_lines The number of lines in each set.
@return A pointer to the allocated cache's set list.
@TODO Handle cases where not enough space can be allocated.
*/
linked_line** make_cache(long num_sets, long num_lines)
{
linked_line** cache = (linked_line**)calloc(num_sets, sizeof(linked_line*));
if (! cache) {
printf("Error: calloc failed\n");
exit(2);
}
long ii;
for (ii = 0; ii < num_sets; ii++) {
cache[ii] = make_set(NULL, num_lines);
}
return cache;
}
/**
Creates a set by creating and linking a given number of lines.
@param newer A pointer to the previously-created element of the set.
@param num_lines The number of lines remaining to be added.
@return A pointer to the created line.
@bug Large values for num_lines result in a segfault in the call to calloc.
@TODO Free already-allocated space in event of allocation failure.
*/
linked_line* make_set(linked_line* newer, long num_lines) {
linked_line* current = (linked_line*)calloc(1, sizeof(linked_line));
if (! current) {
printf("Error: calloc failed\n");
exit(2);
}
current->newer = newer;
num_lines--;
if (num_lines) { // If not on the last line
current->older = make_set(current, num_lines);
}
else {
current->older = NULL;
}
return current;
}
/**
@param cache A pointer to the cache to free.
@param num_sets The number of sets in the cache.
*/
void free_cache(linked_line** cache, long num_sets)
{
int ii;
for (ii = 0; ii < num_sets; ii++) {
free_set(cache[ii]);
}
free(cache);
}
/**
Frees a set by recursing through it, then freeing each element from oldest to newest.
@param line A pointer to the next line in the set.
@param num_lines The number
*/
void free_set(linked_line* line) {
if (line != NULL) {
free_set(line->older);
free(line);
}
}
/************************** CACHE VIEWING FUNCTIONS **************************/
/**
@cache The cache to print.
@cache num_sets The number of sets in the cache.
*/
void print_cache(linked_line** cache, long num_sets)
{
int ii;
for (ii = 0; ii < num_sets; ii++) {
print_set(cache[ii]);
}
}
/**
Prints a cache line and all lines modified less recently than it in its set.<br />
The format is: <br />
address validity.tag address of newer:address of older
@param line The set/line to print, or NULL. If null, does nothing.
*/
void print_set(linked_line* line)
{
if (line != NULL) {
print_set(line->older);
printf("%p %x.%lx\t\t%p:%p\n", (void *) line, line->validity,
line->tag, (void *) line->newer, (void *) line->older);
}
}
/*************************** CACHE ACCESS FUNCTIONS ***************************/
/**
Simulates a cache access operation.
@param cache The cache to access.
@param address The address to access in the cache.
@param set_bits The number of set bits in the address.
@param block_offset_bits The number of block offset bits in the address.
@param num_lines The number of lines per set.
@return 'H' if a hit, 'M' if a miss, 'E' if a miss and eviction
@TODO Pass set and tag into cache_access instead of an address and sizes.
@TODO Make the tag and set retrieval a function?
@TODO Make the re-linking of the set into its own function.
*/
char cache_access(linked_line** cache, long address,
int set_bits, int block_offset_bits, long num_lines)
{
char operation;
long tag = address >> set_bits >> block_offset_bits;
long set = (address >> block_offset_bits) & ((1 << set_bits) - 1);
linked_line* set_head = cache[set];
linked_line* line = find_line(set_head, tag);
if (!line->validity) {
operation = 'M';
}
else if (line->tag == tag) {
operation = 'H';
}
else {
operation = 'E';
}
line->tag = tag;
line->validity = 1;
cache[set] = update_set(set_head, line);
return operation;
}
/**
Finds a line in the given set that holds the given tag, or the least-recently
used line if the tag is not in the set, or the next invalid line if not all
of the lines have been used.
@param line Initially, the most-recently-used line in the set. In the
recursion, iterates through the lines in the set.
@returns The first line with a matching tag, the first invalid line,
or the first line without an older (i.e. the end of the set).
*/
linked_line* find_line(linked_line* line, long tag)
{
if (line->tag == tag || !line->validity || !line->older) {
return line;
}
else {
return find_line(line->older, tag);
}
}
/**
Updates the use order of a set by moving the line being accessed in front of
the previously-accessed line and linking the neighbors of the new head.
@param old_head The previous most-recently modified line of the set.
@param new_head The line of the set being accessed.
@return new_head
*/
linked_line* update_set(linked_line* old_head, linked_line* new_head) {
if(!(new_head == old_head)) {
new_head->newer->older = new_head->older;
if(new_head->older) {
new_head->older->newer = new_head->newer;
}
new_head->newer = NULL;
new_head->older = old_head;
old_head->newer = new_head;
}
return new_head;
}