cs2011-cachelab/csim.c

/* 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
*/

/**** 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_bits, long num_lines);
linked_line* find_line(linked_line* set_head, long tag);
//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_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 = (uint8_t)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_bits = (uint8_t)parse_int_arg(optarg, 'b');
			block_size = bits_to_size(block_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_bits, num_lines);
		increment_result_counters(r, &score);
		if (op == 'M') { //Access again if modifying
		    r = cache_access(cache, address, set_index_bits, block_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 size_t.
   @param arg The string to parse.
   @param opt The option being parsed. If 'E', the output can not be 0.
   @return The parsed long integer if the argument was an integer.
   @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' || (!i && opt=='E')) { // associativity can not be zero
		printf("Invalid argument \"%s\" for option -%c\n", arg, opt);
		bad_usage_error();
	}
	else if (i < 0) {
		printf("Argument %ld for option %c too small (must be greater than 0)", i, opt);
		exit(1);
	}
	return i;
}

/**
   Calculates a size using a given number of bits.
   @param bits The power of 2 to use.
   @note Exits if number of bits is larger than a size_t.
 */
long bits_to_size(int bits)
{
	int max_shift = 8*sizeof(int);
	if (bits > max_shift-1) {
		printf("Argument %hhd too large (-s and -b must be less than %hhd)", bits, max_shift);
		exit(1);
	}
	return (size_t)1 << bits;
}


/***************************** SUB-MAIN FUNCTIONS *****************************/

void increment_result_counters(char result, results* score)
{
	score->hits += (result == 'H');
	score->misses += (result == 'M' || result == 'E');
	score->evictions += (result == 'E');
	if (result == 'H') mprintf(" hit");
	if (result == 'M') mprintf(" miss");
	if (result == 'E') mprintf(" miss eviction");
}



/********************* CACHE CREATION/DELETION FUNCTIONS  *********************/

linked_line** make_cache(long num_sets, long num_lines)
{
	linked_line** cache = (linked_line**)calloc(num_sets, sizeof(linked_line*));
	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.
*/
linked_line* make_set(linked_line* newer, long num_lines) {
	linked_line* current = (linked_line*)calloc(1, sizeof(linked_line));
	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;
}

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  **************************/

void print_cache(linked_line** cache, long num_sets)
{
	int ii;
	for (ii = 0; ii < num_sets; ii++) {
		print_set(cache[ii]);
	}
}

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 ***************************/

char cache_access(linked_line** cache, long address,
				  int set_bits, int block_bits, long num_lines)
{
	char out;
	long tag = address >> set_bits >> block_bits;
	long set = (address >> block_bits) & ((1 << set_bits) - 1);
	linked_line* set_head = cache[set];
	linked_line* line = find_line(set_head, tag);

	if (!line->validity)       out = 'M';
	else if (line->tag == tag) out = 'H';
	else                       out = 'E';

	if(!(line == set_head)) {
		line->newer->older = line->older;
		if(line->older)
			line->older->newer = line->newer;
		line->newer = NULL;
		line->older = set_head;
		set_head->newer = line;
		cache[set] = line;
	}

	line->tag = tag;
	line->validity = 1;

	return out;
}

/**
   @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);
}