Initial

Makefile

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+#
+# Students' Makefile for the Malloc Lab
+#
+TEAM = MA
+VERSION = 1
+HANDINDIR = /afs/cs.cmu.edu/academic/class/15213-f01/malloclab/handin
+
+CC = gcc
+CWI = -Wno-unused-variable -Wno-format
+CFLAGS = -Wall -O2 -m32 $(CWI)
+
+
+OBJS = mdriver.o mm.o memlib.o fsecs.o fcyc.o clock.o ftimer.o
+
+mdriver: $(OBJS)
+	$(CC) $(CFLAGS) -o mdriver $(OBJS)
+
+mdriver.o: mdriver.c fsecs.h fcyc.h clock.h memlib.h config.h mm.h
+memlib.o: memlib.c memlib.h
+mm.o: mm.c mm.h memlib.h
+fsecs.o: fsecs.c fsecs.h config.h
+fcyc.o: fcyc.c fcyc.h
+ftimer.o: ftimer.c ftimer.h config.h
+clock.o: clock.c clock.h
+
+handin:
+	cp mm.c $(HANDINDIR)/$(TEAM)-$(VERSION)-mm.c
+
+clean:
+	rm -f *~ *.o mdriver
+
+

README

@@ -0,0 +1,52 @@
+#####################################################################
+# CS:APP Malloc Lab
+# Handout files for students
+#
+# Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved.
+# May not be used, modified, or copied without permission.
+#
+######################################################################
+
+***********
+Main Files:
+***********
+
+mm.{c,h}	
+	Your solution malloc package. mm.c is the file that you
+	will be handing in, and is the only file you should modify.
+
+mdriver.c	
+	The malloc driver that tests your mm.c file
+
+short{1,2}-bal.rep
+	Two tiny tracefiles to help you get started. 
+
+Makefile	
+	Builds the driver
+
+**********************************
+Other support files for the driver
+**********************************
+
+config.h	Configures the malloc lab driver
+fsecs.{c,h}	Wrapper function for the different timer packages
+clock.{c,h}	Routines for accessing the Pentium and Alpha cycle counters
+fcyc.{c,h}	Timer functions based on cycle counters
+ftimer.{c,h}	Timer functions based on interval timers and gettimeofday()
+memlib.{c,h}	Models the heap and sbrk function
+
+*******************************
+Building and running the driver
+*******************************
+To build the driver, type "make" to the shell.
+
+To run the driver on a tiny test trace:
+
+	unix> mdriver -V -f short1-bal.rep
+
+The -V option prints out helpful tracing and summary information.
+
+To get a list of the driver flags:
+
+	unix> mdriver -h
+

clock.c

@@ -0,0 +1,279 @@
+/* 
+ * clock.c - Routines for using the cycle counters on x86, 
+ *           Alpha, and Sparc boxes.
+ * 
+ * Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved.
+ * May not be used, modified, or copied without permission.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/times.h>
+#include "clock.h"
+
+
+/******************************************************* 
+ * Machine dependent functions 
+ *
+ * Note: the constants __i386__ and  __alpha
+ * are set by GCC when it calls the C preprocessor
+ * You can verify this for yourself using gcc -v.
+ *******************************************************/
+
+#if defined(__i386__)  
+/*******************************************************
+ * Pentium versions of start_counter() and get_counter()
+ *******************************************************/
+
+
+/* $begin x86cyclecounter */
+/* Initialize the cycle counter */
+static unsigned cyc_hi = 0;
+static unsigned cyc_lo = 0;
+
+
+/* Set *hi and *lo to the high and low order bits  of the cycle counter.  
+   Implementation requires assembly code to use the rdtsc instruction. */
+void access_counter(unsigned *hi, unsigned *lo)
+{
+    asm("rdtsc; movl %%edx,%0; movl %%eax,%1"   /* Read cycle counter */
+	: "=r" (*hi), "=r" (*lo)                /* and move results to */
+	: /* No input */                        /* the two outputs */
+	: "%edx", "%eax");
+}
+
+/* Record the current value of the cycle counter. */
+void start_counter()
+{
+    access_counter(&cyc_hi, &cyc_lo);
+}
+
+/* Return the number of cycles since the last call to start_counter. */
+double get_counter()
+{
+    unsigned ncyc_hi, ncyc_lo;
+    unsigned hi, lo, borrow;
+    double result;
+
+    /* Get cycle counter */
+    access_counter(&ncyc_hi, &ncyc_lo);
+
+    /* Do double precision subtraction */
+    lo = ncyc_lo - cyc_lo;
+    borrow = lo > ncyc_lo;
+    hi = ncyc_hi - cyc_hi - borrow;
+    result = (double) hi * (1 << 30) * 4 + lo;
+    if (result < 0) {
+	fprintf(stderr, "Error: counter returns neg value: %.0f\n", result);
+    }
+    return result;
+}
+/* $end x86cyclecounter */
+
+#elif defined(__alpha)
+
+/****************************************************
+ * Alpha versions of start_counter() and get_counter()
+ ***************************************************/
+
+/* Initialize the cycle counter */
+static unsigned cyc_hi = 0;
+static unsigned cyc_lo = 0;
+
+
+/* Use Alpha cycle timer to compute cycles.  Then use
+   measured clock speed to compute seconds 
+*/
+
+/*
+ * counterRoutine is an array of Alpha instructions to access 
+ * the Alpha's processor cycle counter. It uses the rpcc 
+ * instruction to access the counter. This 64 bit register is 
+ * divided into two parts. The lower 32 bits are the cycles 
+ * used by the current process. The upper 32 bits are wall 
+ * clock cycles. These instructions read the counter, and 
+ * convert the lower 32 bits into an unsigned int - this is the 
+ * user space counter value.
+ * NOTE: The counter has a very limited time span. With a 
+ * 450MhZ clock the counter can time things for about 9 
+ * seconds. */
+static unsigned int counterRoutine[] =
+{
+    0x601fc000u,
+    0x401f0000u,
+    0x6bfa8001u
+};
+
+/* Cast the above instructions into a function. */
+static unsigned int (*counter)(void)= (void *)counterRoutine;
+
+
+void start_counter()
+{
+    /* Get cycle counter */
+    cyc_hi = 0;
+    cyc_lo = counter();
+}
+
+double get_counter()
+{
+    unsigned ncyc_hi, ncyc_lo;
+    unsigned hi, lo, borrow;
+    double result;
+    ncyc_lo = counter();
+    ncyc_hi = 0;
+    lo = ncyc_lo - cyc_lo;
+    borrow = lo > ncyc_lo;
+    hi = ncyc_hi - cyc_hi - borrow;
+    result = (double) hi * (1 << 30) * 4 + lo;
+    if (result < 0) {
+	fprintf(stderr, "Error: Cycle counter returning negative value: %.0f\n", result);
+    }
+    return result;
+}
+
+#else
+
+/****************************************************************
+ * All the other platforms for which we haven't implemented cycle
+ * counter routines. Newer models of sparcs (v8plus) have cycle
+ * counters that can be accessed from user programs, but since there
+ * are still many sparc boxes out there that don't support this, we
+ * haven't provided a Sparc version here.
+ ***************************************************************/
+
+void start_counter()
+{
+    printf("ERROR: You are trying to use a start_counter routine in clock.c\n");
+    printf("that has not been implemented yet on this platform.\n");
+    printf("Please choose another timing package in config.h.\n");
+    exit(1);
+}
+
+double get_counter() 
+{
+    printf("ERROR: You are trying to use a get_counter routine in clock.c\n");
+    printf("that has not been implemented yet on this platform.\n");
+    printf("Please choose another timing package in config.h.\n");
+    exit(1);
+}
+#endif
+
+
+
+
+/*******************************
+ * Machine-independent functions
+ ******************************/
+double ovhd()
+{
+    /* Do it twice to eliminate cache effects */
+    int i;
+    double result;
+
+    for (i = 0; i < 2; i++) {
+	start_counter();
+	result = get_counter();
+    }
+    return result;
+}
+
+/* $begin mhz */
+/* Estimate the clock rate by measuring the cycles that elapse */ 
+/* while sleeping for sleeptime seconds */
+double mhz_full(int verbose, int sleeptime)
+{
+    double rate;
+
+    start_counter();
+    sleep(sleeptime);
+    rate = get_counter() / (1e6*sleeptime);
+    if (verbose) 
+	printf("Processor clock rate ~= %.1f MHz\n", rate);
+    return rate;
+}
+/* $end mhz */
+
+/* Version using a default sleeptime */
+double mhz(int verbose)
+{
+    return mhz_full(verbose, 2);
+}
+
+/** Special counters that compensate for timer interrupt overhead */
+
+static double cyc_per_tick = 0.0;
+
+#define NEVENT 100
+#define THRESHOLD 1000
+#define RECORDTHRESH 3000
+
+/* Attempt to see how much time is used by timer interrupt */
+static void callibrate(int verbose)
+{
+    double oldt;
+    struct tms t;
+    clock_t oldc;
+    int e = 0;
+
+    times(&t);
+    oldc = t.tms_utime;
+    start_counter();
+    oldt = get_counter();
+    while (e <NEVENT) {
+	double newt = get_counter();
+
+	if (newt-oldt >= THRESHOLD) {
+	    clock_t newc;
+	    times(&t);
+	    newc = t.tms_utime;
+	    if (newc > oldc) {
+		double cpt = (newt-oldt)/(newc-oldc);
+		if ((cyc_per_tick == 0.0 || cyc_per_tick > cpt) && cpt > RECORDTHRESH)
+		    cyc_per_tick = cpt;
+		/*
+		  if (verbose)
+		  printf("Saw event lasting %.0f cycles and %d ticks.  Ratio = %f\n",
+		  newt-oldt, (int) (newc-oldc), cpt);
+		*/
+		e++;
+		oldc = newc;
+	    }
+	    oldt = newt;
+	}
+    }
+    if (verbose)
+	printf("Setting cyc_per_tick to %f\n", cyc_per_tick);
+}
+
+static clock_t start_tick = 0;
+
+void start_comp_counter() 
+{
+    struct tms t;
+
+    if (cyc_per_tick == 0.0)
+	callibrate(0);
+    times(&t);
+    start_tick = t.tms_utime;
+    start_counter();
+}
+
+double get_comp_counter() 
+{
+    double time = get_counter();
+    double ctime;
+    struct tms t;
+    clock_t ticks;
+
+    times(&t);
+    ticks = t.tms_utime - start_tick;
+    ctime = time - ticks*cyc_per_tick;
+    /*
+      printf("Measured %.0f cycles.  Ticks = %d.  Corrected %.0f cycles\n",
+      time, (int) ticks, ctime);
+    */
+    return ctime;
+}
+

clock.h

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+/* Routines for using cycle counter */
+
+/* Start the counter */
+void start_counter();
+
+/* Get # cycles since counter started */
+double get_counter();
+
+/* Measure overhead for counter */
+double ovhd();
+
+/* Determine clock rate of processor (using a default sleeptime) */
+double mhz(int verbose);
+
+/* Determine clock rate of processor, having more control over accuracy */
+double mhz_full(int verbose, int sleeptime);
+
+/** Special counters that compensate for timer interrupt overhead */
+
+void start_comp_counter();
+
+double get_comp_counter();

config.h

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+#ifndef __CONFIG_H_
+#define __CONFIG_H_
+
+/*
+ * config.h - malloc lab configuration file
+ *
+ * Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved.
+ * May not be used, modified, or copied without permission.
+ */
+
+/*
+ * This is the default path where the driver will look for the
+ * default tracefiles. You can override it at runtime with the -t flag.
+ */
+#define TRACEDIR "./traces/"
+
+/*
+ * This is the list of default tracefiles in TRACEDIR that the driver
+ * will use for testing. Modify this if you want to add or delete
+ * traces from the driver's test suite. For example, if you don't want
+ * your students to implement realloc, you can delete the last two
+ * traces.
+ */
+#define DEFAULT_TRACEFILES \
+  "amptjp-bal.rep",\
+  "cccp-bal.rep",\
+  "cp-decl-bal.rep",\
+  "expr-bal.rep",\
+  "coalescing-bal.rep",\
+  "random-bal.rep",\
+  "random2-bal.rep",\
+  "binary-bal.rep",\
+  "binary2-bal.rep"
+
+/*
+ * This constant gives the estimated performance of the libc malloc
+ * package using our traces on some reference system, typically the
+ * same kind of system the students use. Its purpose is to cap the
+ * contribution of throughput to the performance index. Once the
+ * students surpass the AVG_LIBC_THRUPUT, they get no further benefit
+ * to their score.  This deters students from building extremely fast,
+ * but extremely stupid malloc packages.
+ */
+#define AVG_LIBC_THRUPUT      18944E3  /* 9000 Kops/sec */
+
+ /*
+  * This constant determines the contributions of space utilization
+  * (UTIL_WEIGHT) and throughput (1 - UTIL_WEIGHT) to the performance
+  * index.
+  */
+#define UTIL_WEIGHT .60
+
+/*
+ * Alignment requirement in bytes (either 4 or 8)
+ */
+#define ALIGNMENT 8
+
+/*
+ * Maximum heap size in bytes
+ */
+#define MAX_HEAP (20*(1<<20))  /* 20 MB */
+
+/*****************************************************************************
+ * Set exactly one of these USE_xxx constants to "1" to select a timing method
+ *****************************************************************************/
+#define USE_FCYC   0   /* cycle counter w/K-best scheme (x86 & Alpha only) */
+#define USE_ITIMER 0   /* interval timer (any Unix box) */
+#define USE_GETTOD 1   /* gettimeofday (any Unix box) */
+
+#endif /* __CONFIG_H */

fcyc.c

@@ -0,0 +1,251 @@
+/*
+ * fcyc.c - Estimate the time (in CPU cycles) used by a function f 
+ * 
+ * Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved.
+ * May not be used, modified, or copied without permission.
+ *
+ * Uses the cycle timer routines in clock.c to estimate the
+ * the time in CPU cycles for a function f.
+ */
+#include <stdlib.h>
+#include <sys/times.h>
+#include <stdio.h>
+
+#include "fcyc.h"
+#include "clock.h"
+
+/* Default values */
+#define K 3                  /* Value of K in K-best scheme */
+#define MAXSAMPLES 20        /* Give up after MAXSAMPLES */
+#define EPSILON 0.01         /* K samples should be EPSILON of each other*/
+#define COMPENSATE 0         /* 1-> try to compensate for clock ticks */
+#define CLEAR_CACHE 0        /* Clear cache before running test function */
+#define CACHE_BYTES (1<<19)  /* Max cache size in bytes */
+#define CACHE_BLOCK 32       /* Cache block size in bytes */
+
+static int kbest = K;
+static int maxsamples = MAXSAMPLES;
+static double epsilon = EPSILON;
+static int compensate = COMPENSATE;
+static int clear_cache = CLEAR_CACHE;
+static int cache_bytes = CACHE_BYTES;
+static int cache_block = CACHE_BLOCK;
+
+static int *cache_buf = NULL;
+
+static double *values = NULL;
+static int samplecount = 0;
+
+/* for debugging only */
+#define KEEP_VALS 0
+#define KEEP_SAMPLES 0
+
+#if KEEP_SAMPLES
+static double *samples = NULL;
+#endif
+
+/* 
+ * init_sampler - Start new sampling process 
+ */
+static void init_sampler()
+{
+    if (values)
+	free(values);
+    values = calloc(kbest, sizeof(double));
+#if KEEP_SAMPLES
+    if (samples)
+	free(samples);
+    /* Allocate extra for wraparound analysis */
+    samples = calloc(maxsamples+kbest, sizeof(double));
+#endif
+    samplecount = 0;
+}
+
+/* 
+ * add_sample - Add new sample  
+ */
+static void add_sample(double val)
+{
+    int pos = 0;
+    if (samplecount < kbest) {
+	pos = samplecount;
+	values[pos] = val;
+    } else if (val < values[kbest-1]) {
+	pos = kbest-1;
+	values[pos] = val;
+    }
+#if KEEP_SAMPLES
+    samples[samplecount] = val;
+#endif
+    samplecount++;
+    /* Insertion sort */
+    while (pos > 0 && values[pos-1] > values[pos]) {
+	double temp = values[pos-1];
+	values[pos-1] = values[pos];
+	values[pos] = temp;
+	pos--;
+    }
+}
+
+/* 
+ * has_converged- Have kbest minimum measurements converged within epsilon? 
+ */
+static int has_converged()
+{
+    return
+	(samplecount >= kbest) &&
+	((1 + epsilon)*values[0] >= values[kbest-1]);
+}
+
+/* 
+ * clear - Code to clear cache 
+ */
+static volatile int sink = 0;
+
+static void clear()
+{
+    int x = sink;
+    int *cptr, *cend;
+    int incr = cache_block/sizeof(int);
+    if (!cache_buf) {
+	cache_buf = malloc(cache_bytes);
+	if (!cache_buf) {
+	    fprintf(stderr, "Fatal error.  Malloc returned null when trying to clear cache\n");
+	    exit(1);
+	}
+    }
+    cptr = (int *) cache_buf;
+    cend = cptr + cache_bytes/sizeof(int);
+    while (cptr < cend) {
+	x += *cptr;
+	cptr += incr;
+    }
+    sink = x;
+}
+
+/*
+ * fcyc - Use K-best scheme to estimate the running time of function f
+ */
+double fcyc(test_funct f, void *argp)
+{
+    double result;
+    init_sampler();
+    if (compensate) {
+	do {
+	    double cyc;
+	    if (clear_cache)
+		clear();
+	    start_comp_counter();
+	    f(argp);
+	    cyc = get_comp_counter();
+	    add_sample(cyc);
+	} while (!has_converged() && samplecount < maxsamples);
+    } else {
+	do {
+	    double cyc;
+	    if (clear_cache)
+		clear();
+	    start_counter();
+	    f(argp);
+	    cyc = get_counter();
+	    add_sample(cyc);
+	} while (!has_converged() && samplecount < maxsamples);
+    }
+#ifdef DEBUG
+    {
+	int i;
+	printf(" %d smallest values: [", kbest);
+	for (i = 0; i < kbest; i++)
+	    printf("%.0f%s", values[i], i==kbest-1 ? "]\n" : ", ");
+    }
+#endif
+    result = values[0];
+#if !KEEP_VALS
+    free(values); 
+    values = NULL;
+#endif
+    return result;  
+}
+
+
+/*************************************************************
+ * Set the various parameters used by the measurement routines 
+ ************************************************************/
+
+/* 
+ * set_fcyc_clear_cache - When set, will run code to clear cache 
+ *     before each measurement. 
+ *     Default = 0
+ */
+void set_fcyc_clear_cache(int clear)
+{
+    clear_cache = clear;
+}
+
+/* 
+ * set_fcyc_cache_size - Set size of cache to use when clearing cache 
+ *     Default = 1<<19 (512KB)
+ */
+void set_fcyc_cache_size(int bytes)
+{
+    if (bytes != cache_bytes) {
+	cache_bytes = bytes;
+	if (cache_buf) {
+	    free(cache_buf);
+	    cache_buf = NULL;
+	}
+    }
+}
+
+/* 
+ * set_fcyc_cache_block - Set size of cache block 
+ *     Default = 32
+ */
+void set_fcyc_cache_block(int bytes) {
+    cache_block = bytes;
+}
+
+
+/* 
+ * set_fcyc_compensate- When set, will attempt to compensate for 
+ *     timer interrupt overhead 
+ *     Default = 0
+ */
+void set_fcyc_compensate(int compensate_arg)
+{
+    compensate = compensate_arg;
+}
+
+/* 
+ * set_fcyc_k - Value of K in K-best measurement scheme
+ *     Default = 3
+ */
+void set_fcyc_k(int k)
+{
+    kbest = k;
+}
+
+/* 
+ * set_fcyc_maxsamples - Maximum number of samples attempting to find 
+ *     K-best within some tolerance.
+ *     When exceeded, just return best sample found.
+ *     Default = 20
+ */
+void set_fcyc_maxsamples(int maxsamples_arg)
+{
+    maxsamples = maxsamples_arg;
+}
+
+/* 
+ * set_fcyc_epsilon - Tolerance required for K-best
+ *     Default = 0.01
+ */
+void set_fcyc_epsilon(double epsilon_arg)
+{
+    epsilon = epsilon_arg;
+}
+
+
+
+
+

fcyc.h

@@ -0,0 +1,68 @@
+/*
+ * fcyc.h - prototypes for the routines in fcyc.c that estimate the
+ *     time in CPU cycles used by a test function f
+ * 
+ * Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved.
+ * May not be used, modified, or copied without permission.
+ *
+ */
+
+/* The test function takes a generic pointer as input */
+typedef void (*test_funct)(void *);
+
+/* Compute number of cycles used by test function f */
+double fcyc(test_funct f, void* argp);
+
+/*********************************************************
+ * Set the various parameters used by measurement routines 
+ *********************************************************/
+
+/* 
+ * set_fcyc_clear_cache - When set, will run code to clear cache 
+ *     before each measurement. 
+ *     Default = 0
+ */
+void set_fcyc_clear_cache(int clear);
+
+/* 
+ * set_fcyc_cache_size - Set size of cache to use when clearing cache 
+ *     Default = 1<<19 (512KB)
+ */
+void set_fcyc_cache_size(int bytes);
+
+/* 
+ * set_fcyc_cache_block - Set size of cache block 
+ *     Default = 32
+ */
+void set_fcyc_cache_block(int bytes);
+
+/* 
+ * set_fcyc_compensate- When set, will attempt to compensate for 
+ *     timer interrupt overhead 
+ *     Default = 0
+ */
+void set_fcyc_compensate(int compensate_arg);
+
+/* 
+ * set_fcyc_k - Value of K in K-best measurement scheme
+ *     Default = 3
+ */
+void set_fcyc_k(int k);
+
+/* 
+ * set_fcyc_maxsamples - Maximum number of samples attempting to find 
+ *     K-best within some tolerance.
+ *     When exceeded, just return best sample found.
+ *     Default = 20
+ */
+void set_fcyc_maxsamples(int maxsamples_arg);
+
+/* 
+ * set_fcyc_epsilon - Tolerance required for K-best
+ *     Default = 0.01
+ */
+void set_fcyc_epsilon(double epsilon_arg);
+
+
+
+

fsecs.c

@@ -0,0 +1,57 @@
+/****************************
+ * High-level timing wrappers
+ ****************************/
+#include <stdio.h>
+#include "fsecs.h"
+#include "fcyc.h"
+#include "clock.h"
+#include "ftimer.h"
+#include "config.h"
+
+static double Mhz;  /* estimated CPU clock frequency */
+
+extern int verbose; /* -v option in mdriver.c */
+
+/*
+ * init_fsecs - initialize the timing package
+ */
+void init_fsecs(void)
+{
+    Mhz = 0; /* keep gcc -Wall happy */
+
+#if USE_FCYC
+    if (verbose)
+	printf("Measuring performance with a cycle counter.\n");
+
+    /* set key parameters for the fcyc package */
+    set_fcyc_maxsamples(20); 
+    set_fcyc_clear_cache(1);
+    set_fcyc_compensate(1);
+    set_fcyc_epsilon(0.01);
+    set_fcyc_k(3);
+    Mhz = mhz(verbose > 0);
+#elif USE_ITIMER
+    if (verbose)
+	printf("Measuring performance with the interval timer.\n");
+#elif USE_GETTOD
+    if (verbose)
+	printf("Measuring performance with gettimeofday().\n");
+#endif
+}
+
+/*
+ * fsecs - Return the running time of a function f (in seconds)
+ */
+double fsecs(fsecs_test_funct f, void *argp) 
+{
+#if USE_FCYC
+    double cycles = fcyc(f, argp);
+    return cycles/(Mhz*1e6);
+#elif USE_ITIMER
+    return ftimer_itimer(f, argp, 10);
+#elif USE_GETTOD
+    return ftimer_gettod(f, argp, 10);
+#endif 
+}
+
+

fsecs.h

@@ -0,0 +1,4 @@
+typedef void (*fsecs_test_funct)(void *);
+
+void init_fsecs(void);
+double fsecs(fsecs_test_funct f, void *argp);

ftimer.c

@@ -0,0 +1,106 @@
+/*
+ * ftimer.c - Estimate the time (in seconds) used by a function f 
+ * 
+ * Copyright (c) 2002, R. Bryant and D. O'Hallaron, All rights reserved.
+ * May not be used, modified, or copied without permission.
+ *
+ * Function timers that estimate the running time (in seconds) of a function f.
+ *    ftimer_itimer: version that uses the interval timer
+ *    ftimer_gettod: version that uses gettimeofday
+ */
+#include <stdio.h>
+#include <sys/time.h>
+#include "ftimer.h"
+
+/* function prototypes */
+static void init_etime(void);
+static double get_etime(void);
+
+/* 
+ * ftimer_itimer - Use the interval timer to estimate the running time
+ * of f(argp). Return the average of n runs.  
+ */
+double ftimer_itimer(ftimer_test_funct f, void *argp, int n)
+{
+    double start, tmeas;
+    int i;
+
+    init_etime();
+    start = get_etime();
+    for (i = 0; i < n; i++) 
+	f(argp);
+    tmeas = get_etime() - start;
+    return tmeas / n;
+}
+
+/* 
+ * ftimer_gettod - Use gettimeofday to estimate the running time of
+ * f(argp). Return the average of n runs.  
+ */
+double ftimer_gettod(ftimer_test_funct f, void *argp, int n)
+{
+    int i;
+    struct timeval stv, etv;
+    double diff;
+
+    gettimeofday(&stv, NULL);
+    for (i = 0; i < n; i++) 
+	f(argp);
+    gettimeofday(&etv,NULL);
+    diff = 1E3*(etv.tv_sec - stv.tv_sec) + 1E-3*(etv.tv_usec-stv.tv_usec);
+    diff /= n;
+    return (1E-3*diff);
+}
+
+
+/*
+ * Routines for manipulating the Unix interval timer
+ */
+
+/* The initial value of the interval timer */
+#define MAX_ETIME 86400   
+
+/* static variables that hold the initial value of the interval timer */
+static struct itimerval first_u; /* user time */
+static struct itimerval first_r; /* real time */
+static struct itimerval first_p; /* prof time*/
+
+/* init the timer */
+static void init_etime(void)
+{
+    first_u.it_interval.tv_sec = 0;
+    first_u.it_interval.tv_usec = 0;
+    first_u.it_value.tv_sec = MAX_ETIME;
+    first_u.it_value.tv_usec = 0;
+    setitimer(ITIMER_VIRTUAL, &first_u, NULL);
+
+    first_r.it_interval.tv_sec = 0;
+    first_r.it_interval.tv_usec = 0;
+    first_r.it_value.tv_sec = MAX_ETIME;
+    first_r.it_value.tv_usec = 0;
+    setitimer(ITIMER_REAL, &first_r, NULL);
+   
+    first_p.it_interval.tv_sec = 0;
+    first_p.it_interval.tv_usec = 0;
+    first_p.it_value.tv_sec = MAX_ETIME;
+    first_p.it_value.tv_usec = 0;
+    setitimer(ITIMER_PROF, &first_p, NULL);
+}
+
+/* return elapsed real seconds since call to init_etime */
+static double get_etime(void) {
+    struct itimerval v_curr;
+    struct itimerval r_curr;
+    struct itimerval p_curr;
+
+    getitimer(ITIMER_VIRTUAL, &v_curr);
+    getitimer(ITIMER_REAL,&r_curr);
+    getitimer(ITIMER_PROF,&p_curr);
+
+    return (double) ((first_p.it_value.tv_sec - r_curr.it_value.tv_sec) +
+		     (first_p.it_value.tv_usec - r_curr.it_value.tv_usec)*1e-6);
+}
+
+
+
+

ftimer.h

@@ -0,0 +1,14 @@
+/* 
+ * Function timers 
+ */
+typedef void (*ftimer_test_funct)(void *); 
+
+/* Estimate the running time of f(argp) using the Unix interval timer.
+   Return the average of n runs */
+double ftimer_itimer(ftimer_test_funct f, void *argp, int n);
+
+
+/* Estimate the running time of f(argp) using gettimeofday 
+   Return the average of n runs */
+double ftimer_gettod(ftimer_test_funct f, void *argp, int n);
+

memlib.c

@@ -0,0 +1,101 @@
+/*
+ * memlib.c - a module that simulates the memory system.  Needed because it 
+ *            allows us to interleave calls from the student's malloc package 
+ *            with the system's malloc package in libc.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <string.h>
+#include <errno.h>
+
+#include "memlib.h"
+#include "config.h"
+
+/* private variables */
+static char *mem_start_brk;  /* points to first byte of heap */
+static char *mem_brk;        /* points to last byte of heap */
+static char *mem_max_addr;   /* largest legal heap address */ 
+
+/* 
+ * mem_init - initialize the memory system model
+ */
+void mem_init(void)
+{
+    /* allocate the storage we will use to model the available VM */
+    if ((mem_start_brk = (char *)malloc(MAX_HEAP)) == NULL) {
+	fprintf(stderr, "mem_init_vm: malloc error\n");
+	exit(1);
+    }
+
+    mem_max_addr = mem_start_brk + MAX_HEAP;  /* max legal heap address */
+    mem_brk = mem_start_brk;                  /* heap is empty initially */
+}
+
+/* 
+ * mem_deinit - free the storage used by the memory system model
+ */
+void mem_deinit(void)
+{
+    free(mem_start_brk);
+}
+
+/*
+ * mem_reset_brk - reset the simulated brk pointer to make an empty heap
+ */
+void mem_reset_brk()
+{
+    mem_brk = mem_start_brk;
+}
+
+/* 
+ * mem_sbrk - simple model of the sbrk function. Extends the heap 
+ *    by incr bytes and returns the start address of the new area. In
+ *    this model, the heap cannot be shrunk.
+ */
+void *mem_sbrk(int incr) 
+{
+    char *old_brk = mem_brk;
+
+    if ( (incr < 0) || ((mem_brk + incr) > mem_max_addr)) {
+	errno = ENOMEM;
+	fprintf(stderr, "ERROR: mem_sbrk failed. Ran out of memory...\n");
+	return (void *)-1;
+    }
+    mem_brk += incr;
+    return (void *)old_brk;
+}
+
+/*
+ * mem_heap_lo - return address of the first heap byte
+ */
+void *mem_heap_lo()
+{
+    return (void *)mem_start_brk;
+}
+
+/* 
+ * mem_heap_hi - return address of last heap byte
+ */
+void *mem_heap_hi()
+{
+    return (void *)(mem_brk - 1);
+}
+
+/*
+ * mem_heapsize() - returns the heap size in bytes
+ */
+size_t mem_heapsize() 
+{
+    return (size_t)(mem_brk - mem_start_brk);
+}
+
+/*
+ * mem_pagesize() - returns the page size of the system
+ */
+size_t mem_pagesize()
+{
+    return (size_t)getpagesize();
+}

memlib.h

@@ -0,0 +1,11 @@
+#include <unistd.h>
+
+void mem_init(void);               
+void mem_deinit(void);
+void *mem_sbrk(int incr);
+void mem_reset_brk(void); 
+void *mem_heap_lo(void);
+void *mem_heap_hi(void);
+size_t mem_heapsize(void);
+size_t mem_pagesize(void);
+

mm.c

@@ -0,0 +1,212 @@
+// the allocator uses an implicit free list to manage memory blocks.
+// it provides functionalities for allocation (mm_malloc), deallocation (mm_free), and heap initialization (mm_init). adjacent free blocks are coalesced to reduce fragmentation.
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <string.h>
+#include "mm.h"
+#include "memlib.h"
+
+team_t team = {
+    "MA", "Marvin Aleksa", "marvin.aleksa@stud.uni-due.de", "", ""
+};
+
+#define SIZE_T_SIZE (ALIGN(sizeof(size_t))) // align to size_t bytes
+#define ALIGN(size) (((size) + (7)) & ~0x7) // align to 8 bytes
+#define WSIZE 4           // single word size
+#define DSIZE 8           // double word size
+#define CHUNKSIZE (1<<12) // initial heap size
+#define PACK(size, alloc) ((size) | (alloc))       // pack size and allocated bit
+#define GET(p) (*(unsigned int *)(p))              // read  a word from address
+#define PUT(p, val) (*(unsigned int *)(p) = (val)) // write a word to   address
+#define GET_SIZE(p) (GET(p) & ~0x7) // get size      from address
+#define GET_ALLOC(p) (GET(p) & 0x1) // get alloc bit from address
+#define HDRP(bp) ((char *)(bp) - WSIZE)                      // get address of block header
+#define FTRP(bp) ((char *)(bp) + GET_SIZE(HDRP(bp)) - DSIZE) // get address of block footer
+#define NEXT_BLKP(bp) ((char *)(bp) + GET_SIZE(((char *)(bp) - WSIZE))) // get address of previous block
+#define PREV_BLKP(bp) ((char *)(bp) - GET_SIZE(((char *)(bp) - DSIZE))) // get address of next     block
+#define MAX(x, y) ((x) > (y) ? (x) : (y)) // get maximum value
+
+
+
+// pointer to first block
+static char *heap_listp = 0;
+
+
+
+// find_fit - find a fit for a block with asize bytes.
+static void *find_fit(size_t asize) {
+    char *bp;
+
+    // iterate through heap to find free block
+    for (bp = heap_listp; GET_SIZE(HDRP(bp)) > 0; bp = NEXT_BLKP(bp)) {
+        if (!GET_ALLOC(HDRP(bp)) && (GET_SIZE(HDRP(bp)) >= asize)) {
+            return bp;
+        }
+    }
+    return NULL; // no fit found
+}
+
+
+
+// place - place block of asize bytes at start of free block bp and split if remainder would be at least minimum block size.
+static void place(void *bp, size_t asize) {
+    size_t csize = GET_SIZE(HDRP(bp)); // current block size
+
+    if ((csize - asize) >= (2 * DSIZE)) {      // if remaining size is enough for a new block
+        PUT(HDRP(bp), PACK(asize, 1));         // mark block allocated
+        PUT(FTRP(bp), PACK(asize, 1));
+        bp = NEXT_BLKP(bp);
+        PUT(HDRP(bp), PACK(csize - asize, 0)); // create new free block
+        PUT(FTRP(bp), PACK(csize - asize, 0));
+    } else { // dont split
+        PUT(HDRP(bp), PACK(csize, 1));
+        PUT(FTRP(bp), PACK(csize, 1));
+    }
+}
+
+
+
+// coalesce - boundary tag coalescing. return pointer to coalesced block.
+static void *coalesce(void *bp) {
+    size_t prev_alloc = GET_ALLOC(FTRP(PREV_BLKP(bp)));
+    size_t next_alloc = GET_ALLOC(HDRP(NEXT_BLKP(bp)));
+    size_t size = GET_SIZE(HDRP(bp));
+
+    if (prev_alloc && next_alloc) {            // c1: both adjacent blocks allocated
+        return bp;
+    } else if (prev_alloc && !next_alloc) {    // c2: next block free
+        size += GET_SIZE(HDRP(NEXT_BLKP(bp)));
+        PUT(HDRP(bp), PACK(size, 0));
+        PUT(FTRP(bp), PACK(size, 0));
+    } else if (!prev_alloc && next_alloc) {    // c3: previous block free
+        size += GET_SIZE(HDRP(PREV_BLKP(bp)));
+        PUT(FTRP(bp), PACK(size, 0));
+        PUT(HDRP(PREV_BLKP(bp)), PACK(size, 0));
+        bp = PREV_BLKP(bp);
+    } else {                                  // c4: both blocks free
+        size += GET_SIZE(HDRP(PREV_BLKP(bp))) +
+        GET_SIZE(FTRP(NEXT_BLKP(bp)));
+        PUT(HDRP(PREV_BLKP(bp)), PACK(size, 0));
+        PUT(FTRP(NEXT_BLKP(bp)), PACK(size, 0));
+        bp = PREV_BLKP(bp);
+    }
+
+    return bp;
+}
+
+
+
+// extend_heap - extend heap with free block and return its block pointer.
+static void *extend_heap(size_t words) {
+    char *bp;
+    size_t size;
+
+    // allocate even number of words to maintain alignment
+    size = (words % 2) ? (words + 1) * WSIZE : words * WSIZE;
+    if ((long)(bp = mem_sbrk(size)) == -1)
+        return NULL;
+
+    // initialize free block header/footer + epilogue header
+    PUT(HDRP(bp), PACK(size, 0));         // free block header
+    PUT(FTRP(bp), PACK(size, 0));         // free block footer
+    PUT(HDRP(NEXT_BLKP(bp)), PACK(0, 1)); // new epilogue header
+
+    // coalesce if previous block free
+    return coalesce(bp);
+}
+
+
+
+// mm_init - initialize the malloc package.
+int mm_init(void) {
+    // initialize heap with prologue block, initial free block, epilogue block
+    if ((heap_listp = mem_sbrk(4 * WSIZE)) == (void *)-1){
+        return -1;
+    }
+
+    PUT(heap_listp, 0);                            // alignment padding
+    PUT(heap_listp + (1 * WSIZE), PACK(DSIZE, 1)); // prologue header
+    PUT(heap_listp + (2 * WSIZE), PACK(DSIZE, 1)); // prologue footer
+    PUT(heap_listp + (3 * WSIZE), PACK(0, 1));     // epilogue header
+    heap_listp += (2 * WSIZE);
+
+    // extend empty heap with free block of CHUNKSIZE bytes
+    if (extend_heap(CHUNKSIZE / WSIZE) == NULL){
+        return -1;
+    }
+        
+
+    return 0;
+}
+
+
+
+// mm_malloc - allocate a block of memory with at least the requested size. the block will be aligned to 8 bytes.
+void *mm_malloc(size_t size) {
+    size_t asize;      // adjusted block size
+    size_t extendsize; // amount to extend the heap if no fit found
+    char *bp;
+
+    // ignore spurious requests
+    if (size == 0)
+        return NULL;
+
+    // adjust block size to include overhead and alignment requirements
+    if (size <= DSIZE)
+        asize = 2 * DSIZE; // minimum block size
+        else
+            asize = DSIZE * ((size + (DSIZE) + (DSIZE - 1)) / DSIZE);
+
+    // search free list for a fit
+    if ((bp = find_fit(asize)) != NULL) {
+        place(bp, asize);
+        return bp;
+    }
+
+    // no fit found. get more memory and place block
+    extendsize = MAX(asize, CHUNKSIZE);
+    if ((bp = extend_heap(extendsize / WSIZE)) == NULL)
+        return NULL;
+
+    place(bp, asize);
+    return bp;
+}
+
+
+
+// mm_free - frees a block and coalesces it with adjacent free blocks if possible.
+void mm_free(void *ptr) {
+    if (ptr == NULL) {
+        return; // ignore null pointers
+    }
+
+    // get size of block and mark as free
+    size_t size = GET_SIZE(HDRP(ptr));
+    PUT(HDRP(ptr), PACK(size, 0)); // update header to indicate free
+    PUT(FTRP(ptr), PACK(size, 0)); // update footer to indicate free
+
+    // coalesce block with adjacent free blocks
+    coalesce(ptr);
+}
+
+
+
+// mm_realloc - Implemented simply in terms of mm_malloc and mm_free
+void *mm_realloc(void *ptr, size_t size)
+{
+    void *oldptr = ptr;
+    void *newptr;
+    size_t copySize;
+
+    newptr = mm_malloc(size);
+    if (newptr == NULL)
+        return NULL;
+    copySize = *(size_t *)((char *)oldptr - SIZE_T_SIZE);
+    if (size < copySize)
+        copySize = size;
+    memcpy(newptr, oldptr, copySize);
+    mm_free(oldptr);
+    return newptr;
+}

mm.c_xd

@@ -0,0 +1,84 @@
+/*
+ * mm-naive.c - The fastest, least memory-efficient malloc package.
+ *
+ * In this naive approach, a block is allocated by simply incrementing
+ * the brk pointer.  A block is pure payload. There are no headers or
+ * footers.  Blocks are never coalesced or reused. Realloc is
+ * implemented directly using mm_malloc and mm_free.
+ *
+ * NOTE TO STUDENTS: Replace this header comment with your own header
+ * comment that gives a high level description of your solution.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <string.h>
+
+#include "mm.h"
+#include "memlib.h"
+
+/*********************************************************
+ * NOTE TO STUDENTS: Before you do anything else, please
+ * provide your team information in the following struct.
+ ********************************************************/
+team_t team = {
+    // Team name
+    "MA",
+    // First member's full name
+    "Marvin Aleksa",
+    // First member's email address
+    "marvin.aleksa@stud.uni-due.de",
+    // Second member's full name (leave blank if none)
+    "",
+    // Second member's email address (leave blank if none)
+    ""
+};
+
+// single word (4) or double word (8) alignment
+#define ALIGNMENT 8
+
+// rounds up to the nearest multiple of ALIGNMENT
+#define ALIGN(size) (((size) + (ALIGNMENT-1)) & ~0x7)
+
+
+#define SIZE_T_SIZE (ALIGN(sizeof(size_t)))
+
+// mm_init - initialize the malloc package.
+int mm_init(void){
+    return 0;
+}
+
+// mm_malloc - Allocate a block by incrementing the brk pointer. Always allocate a block whose size is a multiple of the alignment.
+void *mm_malloc(size_t size){
+    int newsize = ALIGN(size + SIZE_T_SIZE);
+    void *p = mem_sbrk(newsize);
+    if (p == (void *)-1)
+        return NULL;
+    else {
+        *(size_t *)p = size;
+        return (void *)((char *)p + SIZE_T_SIZE);
+    }
+}
+
+// mm_free - Freeing a block does nothing.
+void mm_free(void *ptr){
+}
+
+// mm_realloc - Implemented simply in terms of mm_malloc and mm_free
+void *mm_realloc(void *ptr, size_t size){
+    // ATTENTION: You do not need to implement realloc for this assignment
+    void *oldptr = ptr;
+    void *newptr;
+    size_t copySize;
+
+    newptr = mm_malloc(size);
+    if (newptr == NULL)
+        return NULL;
+    copySize = *(size_t *)((char *)oldptr - SIZE_T_SIZE);
+    if (size < copySize)
+        copySize = size;
+    memcpy(newptr, oldptr, copySize);
+    mm_free(oldptr);
+    return newptr;
+}

mm.h

@@ -0,0 +1,23 @@
+#include <stdio.h>
+
+extern int mm_init (void);
+extern void *mm_malloc (size_t size);
+extern void mm_free (void *ptr);
+extern void *mm_realloc(void *ptr, size_t size);
+
+
+/* 
+ * Students work in teams of one or two.  Teams enter their team name, 
+ * personal names and login IDs in a struct of this
+ * type in their bits.c file.
+ */
+typedef struct {
+    char *teamname; /* ID1+ID2 or ID1 */
+    char *name1;    /* full name of first member */
+    char *id1;      /* login ID of first member */
+    char *name2;    /* full name of second member (if any) */
+    char *id2;      /* login ID of second member */
+} team_t;
+
+extern team_t team;
+

mm_v1.c

@@ -0,0 +1,210 @@
+/*
+ * mm-naive.c - The fastest, least memory-efficient malloc package.
+ *
+ * In this naive approach, a block is allocated by simply incrementing
+ * the brk pointer.  A block is pure payload. There are no headers or
+ * footers.  Blocks are never coalesced or reused. Realloc is
+ * implemented directly using mm_malloc and mm_free.
+ *
+ * NOTE TO STUDENTS: Replace this header comment with your own header
+ * comment that gives a high level description of your solution.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "mm.h"
+#include "memlib.h"
+
+team_t team = {
+    /* Team name */
+    "MA",
+    /* First member's full name */
+    "Marvin Aleksa",
+    /* First member's email address */
+    "marvin.aleksa@stud.uni-due.de",
+    /* Second member's full name (leave blank if none) */
+    "",
+    /* Second member's email address (leave blank if none) */
+    ""
+};
+
+typedef uint32_t t4; // 4 byte wide unsigned data type
+typedef uint64_t t8; // 8 byte wide unsigned data type
+
+/* single word (4) or double word (8) alignment */
+#define AL 8       // word length to align to
+#define BS AL*1    // target block size
+
+/* rounds up to the nearest multiple of ALIGNMENT */
+#define ALIGN(size) (((size) + (AL-1)) & ~0x7)
+#define ALIGN_ADDR(addr) (void *)ALIGN((int)addr)
+#define SIZE_T_SIZE (ALIGN(sizeof(t8)))
+
+#define SET_ALL0(x) ((x) & ~1)
+#define SET_ALL1(x) ((x) | 1)
+#define GET_LENG(x) ((x) & ~1)
+#define GET_ALLC(x) ((x) & 1)
+
+void *heap = NULL;
+void *epil = NULL;
+
+void *find_unused(size_t size) {
+    // Start traversing from the beginning of the heap
+    t8 *current = (t8 *)heap;
+
+    while (current < (t8 *)mem_heap_hi()) {
+        size_t block_size = GET_LENG(*current);
+
+        // Check if the block is free and large enough
+        if (!GET_ALLC(*current) && block_size >= size) {
+            return (void *)(current + 1); // Return pointer to payload
+        }
+
+        // Move to the next block
+        current = (t8 *)((char *)current + block_size);
+    }
+
+    // No suitable block found
+    return NULL;
+}
+
+/* mm_init - initialize the malloc package. */
+int mm_init(void) {
+    // printf("\n");
+    heap = mem_sbrk(3*AL);
+    if (heap == (void *)-1) {
+        return 0;
+    }
+
+    // printf("heap start: %p - %p\n", heap, ALIGN_ADDR(heap));
+    t8 *plhd = heap;
+    *plhd = (t8)SET_ALL1(2*AL);
+    // printf("plhd start: %p - %p\n", plhd, ALIGN_ADDR(plhd));
+    // printf("plhd value: %llu\n", GET_LENG(*plhd));
+    // printf("plhd alloc: %llu\n", GET_ALLC(*plhd));
+
+    t8 *plft = heap+8;
+    *plft = (t8)(2*AL);
+    // printf("plft start: %p - %p\n", plft, ALIGN_ADDR(plft));
+    // printf("plft value: %llu\n", GET_LENG(*plft));
+    // printf("plft alloc: %llu\n", GET_ALLC(*plft));
+
+    t8 *elhd = heap+16;
+    *elhd = SET_ALL1(0*AL);
+    // printf("elhd start: %p - %p\n", elhd, ALIGN_ADDR(elhd));
+    // printf("elhd value: %llu\n", GET_LENG(*elhd));
+    // printf("elhd alloc: %llu\n", GET_ALLC(*elhd));
+
+    epil = elhd;
+    // printf("epil start: %p - %p\n", epil, ALIGN_ADDR(epil));
+    // printf("epil value: %llu\n", GET_LENG(*(t8 *)epil));
+    // printf("epil alloc: %llu\n", GET_ALLC(*(t8 *)epil));
+
+    // printf("\n");
+    return 0;
+}
+
+/* mm_malloc - Allocate a block by incrementing the brk pointer. Always allocate a block whose size is a multiple of the alignment. */
+void *mm_malloc(size_t size) {
+    // printf("malloc: request for %u\n", size);
+    int alsize = ALIGN(size);
+    // printf("malloc: aligned to  %lli\n", ALIGN((t8)size));
+    int fbsize = alsize+(2*AL);
+    // printf("malloc: full block size %i - %i\n", fbsize, ALIGN(fbsize));
+
+    void *chk = mem_sbrk(fbsize);
+    if (chk == (void *)-1) {
+        return NULL;
+    }
+
+    t8   *newblock_hd = epil;
+    *newblock_hd = (t8)SET_ALL1(fbsize);
+    // printf("malloc: new block header starts  %p - %p\n", newblock_hd, ALIGN_ADDR(newblock_hd));
+
+    void *newblock_pl = epil+8;
+    // printf("malloc: new block payload starts %p - %p\n", newblock_pl, ALIGN_ADDR(newblock_pl));
+
+    t8   *newblock_ft = epil+8+alsize;
+    *newblock_ft = (t8)SET_ALL0(fbsize);
+    // printf("malloc: new block footer         %p - %p\n", newblock_ft, ALIGN_ADDR(newblock_ft));
+
+    epil = epil+fbsize;
+    t8 *nepil = epil;
+    *nepil = (t8)(SET_ALL1(0));
+    // printf("malloc: new epilogue             %p - %p\n", epil, ALIGN_ADDR(epil));
+
+    // printf("\n");
+    return newblock_pl;
+    // int newsize = ALIGN(size + SIZE_T_SIZE);
+    // void *p = mem_sbrk(newsize);
+    // if (p == (void *)-1)
+    //     return NULL;
+    // else {
+    //     *(size_t *)p = size;
+    //     return (void *)((char *)p + SIZE_T_SIZE);
+    // }
+}
+
+/* mm_free - Freeing a block does nothing. */
+void mm_free(void *ptr) {
+    if (ptr == NULL) {
+        return;
+    }
+
+    // Adjust pointer to get the header of the block
+    t8 *block_header = (t8 *)ptr - 1;
+
+    // Mark the block as free
+    *block_header = SET_ALL0(*block_header);
+
+    // Get the footer for the block
+    size_t block_size = GET_LENG(*block_header);
+    t8 *block_footer = (t8 *)((char *)block_header + block_size - sizeof(t8));
+    *block_footer = *block_header;
+
+    // Try coalescing with previous block if it's free
+    t8 *prev_footer = (t8 *)((char *)block_header - sizeof(t8));
+    if (prev_footer >= (t8 *)mem_heap_lo() && !GET_ALLC(*prev_footer)) {
+        size_t prev_size = GET_LENG(*prev_footer);
+        t8 *prev_header = (t8 *)((char *)block_header - prev_size);
+
+        size_t new_size = prev_size + block_size;
+        *prev_header = SET_ALL0(new_size);
+        *block_footer = *prev_header;
+
+        block_header = prev_header;
+        block_size = new_size;
+    }
+
+    // Try coalescing with next block if it's free
+    t8 *next_header = (t8 *)((char *)block_header + block_size);
+    if (next_header < (t8 *)mem_heap_hi() && !GET_ALLC(*next_header)) {
+        size_t next_size = GET_LENG(*next_header);
+        t8 *next_footer = (t8 *)((char *)next_header + next_size - sizeof(t8));
+
+        size_t new_size = block_size + next_size;
+        *block_header = SET_ALL0(new_size);
+        *next_footer = *block_header;
+    }
+}
+
+/* mm_realloc - Implemented simply in terms of mm_malloc and mm_free */
+void *mm_realloc(void *ptr, size_t size) {
+    void *oldptr = ptr;
+    void *newptr;
+    size_t copySize;
+
+    newptr = mm_malloc(size);
+    if (newptr == NULL)
+        return NULL;
+    copySize = *(size_t *)((char *)oldptr - SIZE_T_SIZE);
+    if (size < copySize)
+        copySize = size;
+    memcpy(newptr, oldptr, copySize);
+    mm_free(oldptr);
+    return newptr;
+}

mm_v2.c

@@ -0,0 +1,168 @@
+/*
+ * mm-naive.c - The fastest, least memory-efficient malloc package.
+ *
+ * In this naive approach, a block is allocated by simply incrementing
+ * the brk pointer.  A block is pure payload. There are no headers or
+ * footers.  Blocks are never coalesced or reused. Realloc is
+ * implemented directly using mm_malloc and mm_free.
+ *
+ * NOTE TO STUDENTS: Replace this header comment with your own header
+ * comment that gives a high level description of your solution.
+ */
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "mm.h"
+#include "memlib.h"
+
+team_t team = {
+    /* Team name */
+    "MA",
+    /* First member's full name */
+    "Marvin Aleksa",
+    /* First member's email address */
+    "marvin.aleksa@stud.uni-due.de",
+    /* Second member's full name (leave blank if none) */
+    "",
+    /* Second member's email address (leave blank if none) */
+    ""
+};
+
+typedef uint16_t t2; // 2  byte wide unsigned data type
+typedef uint32_t t4; // 4 byte wide unsigned data type
+typedef uint64_t t8; // 8 byte wide unsigned data type
+
+typedef struct {
+    uint32_t len;
+    uint32_t plen;
+} Header;
+
+/* single word (4) or double word (8) alignment */
+#define AL 8     // word length to align to
+#define HH 2048 // heap increase increment
+
+/* rounds up to the nearest multiple of ALIGNMENT */
+#define ALIGN(size) (((size) + (AL-1)) & ~0x7)
+#define ALIGN_ADDR(addr) (void *)ALIGN((int)addr)
+#define SIZE_T_SIZE (ALIGN(sizeof(t8)))
+
+#define SET_ALL0(x) ((x) & ~1)
+#define SET_ALL1(x) ((x) | 1)
+#define GET_LENG(x) ((x) & ~1)
+#define GET_ALLC(x) ((x) & 1)
+
+void *heap = NULL;
+void *curs = NULL;
+
+/* mm_init - initialize the malloc package. */
+int mm_init(void) {
+    printf("\n");
+    heap = mem_sbrk( HH );
+    if (heap == (void *)-1) {
+        return -1;
+    }
+    curs = heap;
+
+    printf("init -> first heap addr %p (%p)\n", mem_heap_lo(), ALIGN_ADDR(mem_heap_lo()));
+    // printf("init -> first heap addr %p\n", heap);
+    printf("init -> heap cursor at  %p\n", curs);
+    printf("init ->       heap size %i\n", mem_heapsize());
+    printf("init -> final heap addr %p\n", mem_heap_hi());
+
+    printf("\n");
+    return 0;
+}
+
+/* mm_malloc - Allocate a block by incrementing the brk pointer. Always allocate a block whose size is a multiple of the alignment. */
+void *mm_malloc(size_t size) {
+    int nbs = ALIGN(size); //new block size
+    printf("malloc -> %i requested, aligned to %i\n", size, nbs);
+    nbs += 2 * sizeof( t8 );
+    printf("malloc -> extended to %i for overhead\n", nbs);
+    if( ( nbs ) <= ( mem_heap_hi() - curs ) ){
+        printf("malloc -> %i requested, %i available\n", nbs, ( mem_heap_hi() - curs ));
+        printf("malloc -> heap size %i\n", mem_heapsize());
+    } else {
+        printf("malloc -> %i requested, %i available, allocating extra %i bytes\n", nbs, ( mem_heap_hi() - curs ), HH);
+        printf("malloc -> new heap size %i\n", mem_heapsize());
+        heap = mem_sbrk( HH );
+    }
+
+    curs = curs + sizeof(t8) + size;
+
+    printf("\n");
+    return curs;
+    // int newsize = ALIGN(size + SIZE_T_SIZE);
+    // void *p = mem_sbrk(newsize);
+    // if (p == (void *)-1)
+    //     return NULL;
+    // else {
+    //     *(size_t *)p = size;
+    //     return (void *)((char *)p + SIZE_T_SIZE);
+    // }
+}
+
+/* mm_free - Freeing a block does nothing. */
+void mm_free(void *ptr) {
+    if (ptr == NULL) {
+        return;
+    }
+
+    // Adjust pointer to get the header of the block
+    t8 *block_header = (t8 *)ptr - 1;
+
+    // Mark the block as free
+    *block_header = SET_ALL0(*block_header);
+
+    // Get the footer for the block
+    size_t block_size = GET_LENG(*block_header);
+    t8 *block_footer = (t8 *)((char *)block_header + block_size - sizeof(t8));
+    *block_footer = *block_header;
+
+    // Try coalescing with previous block if it's free
+    t8 *prev_footer = (t8 *)((char *)block_header - sizeof(t8));
+    if (prev_footer >= (t8 *)mem_heap_lo() && !GET_ALLC(*prev_footer)) {
+        size_t prev_size = GET_LENG(*prev_footer);
+        t8 *prev_header = (t8 *)((char *)block_header - prev_size);
+
+        size_t new_size = prev_size + block_size;
+        *prev_header = SET_ALL0(new_size);
+        *block_footer = *prev_header;
+
+        block_header = prev_header;
+        block_size = new_size;
+    }
+
+    // Try coalescing with next block if it's free
+    t8 *next_header = (t8 *)((char *)block_header + block_size);
+    if (next_header < (t8 *)mem_heap_hi() && !GET_ALLC(*next_header)) {
+        size_t next_size = GET_LENG(*next_header);
+        t8 *next_footer = (t8 *)((char *)next_header + next_size - sizeof(t8));
+
+        size_t new_size = block_size + next_size;
+        *block_header = SET_ALL0(new_size);
+        *next_footer = *block_header;
+    }
+}
+
+/* mm_realloc - Implemented simply in terms of mm_malloc and mm_free */
+void *mm_realloc(void *ptr, size_t size) {
+    void *oldptr = ptr;
+    void *newptr;
+    size_t copySize;
+
+    newptr = mm_malloc(size);
+    if (newptr == NULL)
+        return NULL;
+    copySize = *(size_t *)((char *)oldptr - SIZE_T_SIZE);
+    if (size < copySize)
+        copySize = size;
+    memcpy(newptr, oldptr, copySize);
+    mm_free(oldptr);
+    return newptr;
+}

mm_v3.c

@@ -0,0 +1,116 @@
+/*
+ * mm-naive.c - The fastest, least memory-efficient malloc package.
+ *
+ * In this naive approach, a block is allocated by simply incrementing
+ * the brk pointer.  A block is pure payload. There are no headers or
+ * footers.  Blocks are never coalesced or reused. Realloc is
+ * implemented directly using mm_malloc and mm_free.
+ *
+ * NOTE TO STUDENTS: Replace this header comment with your own header
+ * comment that gives a high level description of your solution.
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdint.h>
+
+#include "mm.h"
+#include "memlib.h"
+
+team_t team = {
+    /* Team name */
+    "MA",
+    /* First member's full name */
+    "Marvin Aleksa",
+    /* First member's email address */
+    "marvin.aleksa@stud.uni-due.de",
+    /* Second member's full name (leave blank if none) */
+    "",
+    /* Second member's email address (leave blank if none) */
+    ""
+};
+
+typedef uint32_t t4; // 4 byte wide unsigned data type
+typedef uint64_t t8; // 8 byte wide unsigned data type
+
+typedef struct {
+    uint32_t ln;
+    void *nx;
+} Header;
+
+/* single word (4) or double word (8) alignment */
+#define AL 8       // word length to align to
+#define PS 4096    // pagesize
+#define BS AL*1    // target block size
+
+/* rounds up to the nearest multiple of ALIGNMENT */
+#define ALIGN(size) (((size) + (AL-1)) & ~0x7)
+#define ALIGN_ADDR(addr) (void *)ALIGN((int)addr)
+#define SIZE_T_SIZE (ALIGN(sizeof(t8)))
+
+#define SET_ALL0(x) ((x) & ~1)
+#define SET_ALL1(x) ((x) | 1)
+#define GET_LENG(x) ((x) & ~1)
+#define GET_ALLC(x) ((x) & 1)
+
+void *heap = NULL;
+
+/* mm_init - initialize the malloc package. */
+int mm_init(void) {
+    // printf("init -> allocating initial heap at %i bytes\n", PS);
+    heap = mem_sbrk(PS);
+    // printf("init -> heap starts at %u + %i bytes\n", mem_heap_lo(), mem_heapsize());
+    // printf("               ends at %u\n", mem_heap_hi());
+
+    Header *first = heap;
+    Header *final = mem_heap_hi();
+    first->ln = SET_ALL1(16);
+    first->nx = final;
+    // printf("init -> first block at %u with ln %i and next %u\n", first, first->ln, first->nx);
+    final->ln = SET_ALL1(0);
+    final->nx = NULL;
+    // printf("init -> final block at %u with ln %i and next %u\n", final, final->ln, final->nx);
+
+
+    // printf("\n");
+    return 0;
+}
+
+/* mm_malloc - Allocate a block by incrementing the brk pointer. Always allocate a block whose size is a multiple of the alignment. */
+void *mm_malloc(size_t size) {
+    // printf("malloc -> %i requested, aligned to + overhead %i\n", size, ALIGN( size ) + 8);
+
+    int newsize = ALIGN(size + SIZE_T_SIZE);
+    void *p = mem_sbrk(newsize);
+    if (p == (void *)-1)
+        return NULL;
+    else {
+        *(size_t *)p = size;
+        return (void *)((char *)p + SIZE_T_SIZE);
+    }
+    // printf("\n");
+}
+
+/* mm_free - Freeing a block does nothing. */
+void mm_free(void *ptr) {
+
+}
+
+/* mm_realloc - Implemented simply in terms of mm_malloc and mm_free */
+void *mm_realloc(void *ptr, size_t size) {
+    void *oldptr = ptr;
+    void *newptr;
+    size_t copySize;
+
+    newptr = mm_malloc(size);
+    if (newptr == NULL)
+        return NULL;
+    copySize = *(size_t *)((char *)oldptr - SIZE_T_SIZE);
+    if (size < copySize)
+        copySize = size;
+    memcpy(newptr, oldptr, copySize);
+    mm_free(oldptr);
+    return newptr;
+}

short1-bal.rep

@@ -0,0 +1,16 @@
+20000
+6
+12
+1
+a 0 2040
+a 1 2040
+f 1
+a 2 48
+a 3 4072
+f 3
+a 4 4072
+f 0
+f 2
+a 5 4072
+f 4
+f 5

short2-bal.rep

@@ -0,0 +1,16 @@
+20000
+6
+12
+1
+a 0 2040
+a 1 4010
+a 2 48
+a 3 4072
+a 4 4072
+a 5 4072
+f 0
+f 1
+f 2
+f 3
+f 4
+f 5