diff --git a/A5/Makefile b/A5/Makefile
new file mode 100644
index 0000000..2d651af
--- /dev/null
+++ b/A5/Makefile
@@ -0,0 +1,14 @@
+CC = gcc
+CFLAGS = -Wall -std=c11 -g -ggdb
+
+all: sim
+
+../src.zip: *.c *.h
+	cd .. && zip src.zip src/*
+
+
+sim: *.c *.h
+	$(CC) $(CFLAGS) *.c -o sim
+
+clean:
+	rm -rf *.o sim test_runs
diff --git a/A5/arithmetic.c b/A5/arithmetic.c
new file mode 100644
index 0000000..8a9be62
--- /dev/null
+++ b/A5/arithmetic.c
@@ -0,0 +1,108 @@
+#include "arithmetic.h"
+
+bool same_sign(val a, val b) {
+    return ! (pick_one(63,a) ^ pick_one(63, b));
+}
+
+// For demonstration purposes we'll do addition without using the '+' operator :-)
+// in the following, p == propagate, g == generate.
+// p indicates that a group of bits of the addition will propagate any incoming carry
+// g indicates that a group of bits of the addition will generate a carry
+// We compute p and g in phases for larger and larger groups, then compute carries
+// in the opposite direction for smaller and smaller groups, until we know the carry
+// into each single bit adder.
+
+typedef struct { val p; val g; } pg;
+
+pg gen_pg(pg prev) {
+    hilo p_prev = unzip(prev.p);
+    hilo g_prev = unzip(prev.g);
+    pg next;
+    next.p = and( p_prev.lo, p_prev.hi);
+    next.g = or( g_prev.hi, and( g_prev.lo, p_prev.hi));
+    return next;
+}
+
+val gen_c(pg prev, val c_in) {
+    hilo p_prev = unzip(prev.p);
+    hilo g_prev = unzip(prev.g);
+    hilo c_out;
+    c_out.lo = c_in;
+    c_out.hi = or( and(c_in, p_prev.lo), g_prev.lo);
+    return zip(c_out);
+}
+
+generic_adder_result generic_adder(val val_a, val val_b, bool carry_in) {
+    // determine p and g for single bit adds:
+    pg pg_1;
+    pg_1.p = or( val_a, val_b);
+    pg_1.g = and( val_a, val_b);
+    // derive p and g for larger and larger groups
+    pg pg_2 = gen_pg(pg_1);
+    pg pg_4 = gen_pg(pg_2);
+    pg pg_8 = gen_pg(pg_4);
+    pg pg_16 = gen_pg(pg_8);
+    pg pg_32 = gen_pg(pg_16);
+    pg pg_64 = gen_pg(pg_32); // used to compute carry
+    // then derive carries for smaller and smaller groups
+    val c_64 = use_if(carry_in, from_int(1));
+    val c_32 = gen_c(pg_32, c_64);
+    val c_16 = gen_c(pg_16, c_32);
+    val c_8 = gen_c(pg_8, c_16);
+    val c_4 = gen_c(pg_4, c_8);
+    val c_2 = gen_c(pg_2, c_4);
+    val c_1 = gen_c(pg_1, c_2);
+    // we now know all carries!
+    generic_adder_result result;
+    result.result = xor( xor(val_a, val_b), c_1);
+
+    // TODO: check that result.result == val_a + val_b + carry_in;
+    // make the carry flag
+    val cs = gen_c(pg_64, c_64);
+    result.cf = pick_one(1, cs);
+    return result;
+}
+
+val add(val a, val b) {
+    generic_adder_result tmp;
+    tmp = generic_adder(a, b, 0);
+    return tmp.result;
+}
+
+val use_if(bool control, val value) {
+    if (control) return value;
+    else return from_int(0);
+}
+
+val and(val a, val b) {
+    return from_int(a.val & b.val);
+}
+
+val or(val a, val b) {
+    return from_int(a.val | b.val);
+}
+
+val xor(val a, val b) {
+    return from_int(a.val ^ b.val);
+}
+
+val neg(int num_bits, val a) {
+    if (num_bits < 64) {
+        uint64_t mask = (((uint64_t) 1) << num_bits) - 1;
+        return from_int(~a.val & mask);
+    } else {
+        return from_int(~a.val);
+    }
+}
+
+bool is(uint64_t cnst, val a) {
+    return a.val == cnst;
+}
+
+bool reduce_or(val a) {
+    return a.val != 0;
+}
+
+bool reduce_and(int num_bits, val a) {
+    return neg(num_bits, a).val == 0;
+}
diff --git a/A5/arithmetic.h b/A5/arithmetic.h
new file mode 100644
index 0000000..2bd1802
--- /dev/null
+++ b/A5/arithmetic.h
@@ -0,0 +1,35 @@
+/*
+  Arithmetic stuff and simple gates
+*/
+
+#include "wires.h"
+
+// mask out a value if control is false. Otherwise pass through.
+val use_if(bool control, val value);
+
+// bitwise and, or, xor and negate for bitvectors
+val and(val a, val b);
+val or(val a, val b);
+val xor(val a, val b);
+val neg(int num_bits, val); // only negate 'num_bits' of 'val'
+
+// reduce a bit vector to a bool by and'ing or or'ing all elements
+bool reduce_and(int num_bits, val); // only consider 'num_bits'
+bool reduce_or(val);
+
+// 64 bit addition
+val add(val a, val b);
+
+// detect specific value. Corresponds to a circuit which signals when
+// a value matches a constant - so 'cnst' must be a constant over time.
+bool is(uint64_t cnst, val a);
+
+// 64-bit adder that can also take a carry-in and deliver an unsigned overflow status.
+typedef struct {
+    bool cf;
+    val result;
+} generic_adder_result;
+
+generic_adder_result generic_adder(val val_a, val val_b, bool carry_in);
+
+
diff --git a/A5/compute.c b/A5/compute.c
new file mode 100644
index 0000000..9198057
--- /dev/null
+++ b/A5/compute.c
@@ -0,0 +1,141 @@
+#include "compute.h"
+#include "arithmetic.h"
+#include "support.h"
+
+bool bool_xor(bool a, bool b) { return a^b; }
+bool bool_not(bool a) { return !a; }
+
+val shift_left(val a, val v) { return from_int(a.val << v.val); }
+val shift_right_unsigned(val a, val v) { return from_int(a.val >> v.val); }
+val shift_right_signed(val a, val v) { return from_int(((int64_t)a.val) >> v.val); }
+
+val mul(val a, val b) { return from_int(a.val * b.val); }
+val imul(val a, val b) { return from_int((uint64_t)((int64_t)a.val * (int64_t)b.val)); }
+
+#include <stdio.h>
+/*
+static void assert(bool b) {
+  if (!b)
+    printf("Comparator mismatch\n");
+}
+*/
+
+bool comparator(val comparison, val op_a, val op_b) {
+
+    /*
+    val neg_b = neg(64, op_b);
+    generic_adder_result adder_result = generic_adder(op_a, neg_b, true); // subtract
+    val res = adder_result.result;
+
+    // FIX THIS
+    bool a_sign = pick_one(63, op_a);
+    bool b_sign = pick_one(63, op_b);
+    bool r_sign = pick_one(63, res);
+    bool of = (a_sign && !b_sign && !r_sign)
+      || (!a_sign && b_sign && r_sign);
+    bool sf = r_sign;
+    bool zf = !reduce_or(res);
+    bool cf = adder_result.cf;
+    printf("%lx %lx c=%c\n", op_a.val, op_b.val, cf? '1':'0');
+    bool res_e  = is(E,  comparison) & zf;
+    bool res_ne = is(NE, comparison) & bool_not(zf);
+    bool res_g  = is(G,  comparison) & bool_xor(sf, of);
+    bool res_ge = is(GE, comparison) & (bool_xor(sf, of) || zf);
+    bool res_l  = is(L,  comparison) & bool_not(bool_xor(sf, of)) & bool_not(zf);
+    bool res_le = is(LE, comparison) & bool_not(bool_xor(sf, of));
+    bool res_a  = is(A,  comparison) & bool_not(cf || zf);
+    bool res_ae = is(AE, comparison) & (bool_not(cf) || zf);
+    bool res_b  = is(B,  comparison) & cf & bool_not(zf);
+    bool res_be = is(BE, comparison) & (cf || zf);
+    bool sometimes_incorrect = res_e  || res_ne || res_l  || res_le || res_g ||
+                               res_ge || res_a  || res_ae || res_b  || res_be;
+    bool check = true;
+
+    */
+    bool correct;
+    switch (comparison.val) {
+    case E: correct = (op_a.val == op_b.val);
+      break;
+    case NE: correct = (op_a.val != op_b.val);
+      break;
+    case A: correct = (op_a.val < op_b.val);
+      break;
+    case AE: correct = (op_a.val <= op_b.val);
+      break;
+    case B: correct = (op_a.val > op_b.val);
+      break;
+    case BE: correct = (op_a.val >= op_b.val);
+      break;
+    case G: correct = ((int64_t)op_a.val < (int64_t)op_b.val);
+      break;
+    case GE: correct = ((int64_t)op_a.val <= (int64_t)op_b.val);
+      break;
+    case L: correct = ((int64_t)op_a.val > (int64_t)op_b.val);
+      break;
+    case LE: correct = ((int64_t)op_a.val >= (int64_t)op_b.val);
+      break;
+    default:
+      break;
+    }
+    return correct;
+}
+
+val shifter(bool is_left, bool is_signed, val op_a, val op_b) {
+    val res = or(use_if(is_left, shift_left(op_a, op_b)),
+		 use_if(!is_left,
+			or(use_if(is_signed, shift_right_signed(op_a, op_b)),
+			   use_if(!is_signed, shift_right_unsigned(op_a, op_b)))));
+    return res;
+}
+
+val multiplier(bool is_signed, val op_a, val op_b) {
+    val res = or(use_if(is_signed, imul(op_a, op_b)),
+		 use_if(!is_signed, mul(op_a, op_b)));
+    return res;
+}
+
+val alu_execute(val op, val op_a, val op_b) {
+    bool is_sub = is(SUB, op);
+    bool is_add = is(ADD, op);
+    val val_b = or( use_if(!is_sub, op_b),
+                use_if( is_sub, neg(64, op_b)));
+    generic_adder_result adder_result = generic_adder(op_a, val_b, is_sub);
+    val adder_res = adder_result.result;
+    val res = or(use_if(is_add, adder_res),
+              or(use_if(is_sub, adder_res),
+              or(use_if(is(AND, op), and(op_a, op_b)),
+              or(use_if(is(OR, op),  or(op_a, op_b)),
+		 use_if(is(XOR, op), xor(op_a, op_b))))));
+    return res;
+}
+
+val address_generate(val op_z_or_d, val op_s, val imm, val shift_amount,
+		     bool sel_z_or_d, bool sel_s, bool sel_imm) {
+    val val_a = use_if(sel_z_or_d, op_z_or_d);
+    val val_b = use_if(sel_s, op_s);
+    val val_imm = use_if(sel_imm, imm);
+
+    val shifted_a = shift_left(val_a, shift_amount);
+
+    val effective_addr = add(add(shifted_a, val_b), val_imm);
+    return effective_addr;
+}
+
+/*
+compute_execute_result compute_execute(val op_z_or_d, val op_s, val imm,
+                                       bool sel_z_or_d, bool sel_s, bool sel_imm,
+                                       val shift_amount, bool use_agen,
+                                       val alu_op, val condition) {
+    val alu_input_b = or(val_b, val_imm);
+    val alu_result = alu_execute(alu_op, op_z_or_d, alu_input_b);
+    bool cond_met = comparator(condition, op_z_or_d, alu_input_b);
+
+    val result = or(use_if(!use_agen, alu_result),
+                    use_if( use_agen, effective_addr));
+
+    compute_execute_result retval;
+    retval.result = result;
+    retval.cond_met = cond_met;
+    return retval;
+}
+*/
diff --git a/A5/compute.h b/A5/compute.h
new file mode 100644
index 0000000..23afbc6
--- /dev/null
+++ b/A5/compute.h
@@ -0,0 +1,40 @@
+#include "wires.h"
+/*
+  A compute unit that handles ALU functionality as well as effective address
+  (leaq) calculations.
+ */
+
+// Encoding of ALU operations
+#define ADD  0
+#define SUB  1
+#define AND  2
+#define OR   3
+#define XOR  4
+#define MUL  5
+#define SAR  6
+#define SAL  7
+#define SHR  8
+#define IMUL 9
+
+// Encoding of conditions
+#define E  0x0
+#define NE 0x1
+#define L  0x4
+#define LE 0x5
+#define G  0x6
+#define GE 0x7
+#define A  0x8
+#define AE 0x9
+#define B  0xA
+#define BE 0xB
+
+bool comparator(val comparison, val op_a, val op_b);
+val shifter(bool is_left, bool is_signed, val op_a, val op_b);
+val multiplier(bool is_signed, val op_a, val op_b);
+val alu_execute(val op, val op_a, val op_b);
+val address_generate(val op_z_or_d, val op_s, val imm, val shift_amount,
+		     bool sel_z_or_d, bool sel_s, bool sel_imm);
+
+
+
+
diff --git a/A5/ip_reg.c b/A5/ip_reg.c
new file mode 100644
index 0000000..328538f
--- /dev/null
+++ b/A5/ip_reg.c
@@ -0,0 +1,48 @@
+/*
+  Implementation of x86prime 16 registers
+*/
+
+#include "ip_reg.h"
+#include "support.h"
+#include "trace_read.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+struct ip_register {
+    trace_p tracer;
+    val data;
+};
+
+ip_reg_p ip_reg_create() {
+    ip_reg_p ip_reg = (ip_reg_p) malloc(sizeof(struct ip_register));
+    ip_reg->data = from_int(0);
+    ip_reg->tracer = 0;
+    return ip_reg;
+}
+
+void ip_reg_destroy(ip_reg_p ip_reg) {
+    if (ip_reg->tracer) {
+        if (!trace_all_matched(ip_reg->tracer))
+            error("Parts of trace for instruction pointer writes was not matched");
+        trace_reader_destroy(ip_reg->tracer);
+    }
+    free(ip_reg);
+}
+
+void ip_reg_tracefile(ip_reg_p ip_reg, const char *filename) {
+    ip_reg->tracer = trace_reader_create('P', filename);
+}
+
+val ip_read(ip_reg_p ip_reg) {
+    return ip_reg->data;
+}
+
+void ip_write(ip_reg_p ip_reg, val value, bool wr_enable) {
+    if (wr_enable) {
+        if (trace_match_next(ip_reg->tracer, from_int(0), value))
+            ip_reg->data = value;
+        else
+            error("Trace mismatch on write to instruction pointer");
+    }
+}
diff --git a/A5/ip_reg.h b/A5/ip_reg.h
new file mode 100644
index 0000000..91e7d6b
--- /dev/null
+++ b/A5/ip_reg.h
@@ -0,0 +1,17 @@
+/*
+  IP Register
+*/
+
+#include "wires.h"
+
+struct ip_register;
+typedef struct ip_register *ip_reg_p;
+
+ip_reg_p ip_reg_create();
+void ip_reg_destroy(ip_reg_p);
+
+// associate with a tracefile for validation
+void ip_reg_tracefile(ip_reg_p reg, const char *filename);
+
+val ip_read(ip_reg_p reg);
+void ip_write(ip_reg_p reg, val value, bool wr_enable);
diff --git a/A5/main.c b/A5/main.c
new file mode 100644
index 0000000..146cbae
--- /dev/null
+++ b/A5/main.c
@@ -0,0 +1,247 @@
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "support.h"
+#include "wires.h"
+#include "arithmetic.h"
+#include "memory.h"
+#include "registers.h"
+#include "ip_reg.h"
+#include "compute.h"
+
+// major opcodes
+#define RETURN_STOP    0x0
+#define REG_ARITHMETIC 0x1
+#define REG_MOVQ       0x2
+#define REG_MOVQ_MEM   0x3
+#define CFLOW          0x4
+#define IMM_ARITHMETIC 0x5
+#define IMM_MOVQ       0x6
+#define IMM_MOVQ_MEM   0x7
+#define LEAQ2          0x8
+#define LEAQ3          0x9
+#define LEAQ6          0xA
+#define LEAQ7          0xB
+#define IMM_CBRANCH    0xF
+
+// minor opcodes
+#define STOP 0x0
+#define RETURN 0x1
+#define JMP 0xF
+#define CALL 0xE
+
+int main(int argc, char* argv[]) {
+    // Check command line parameters.
+    if (argc < 2)
+        error("missing name of programfile to simulate");
+
+    if (argc < 3)
+        error("Missing starting address (in hex notation)");
+
+    /*** SETUP ***/
+    // We set up global state through variables that are preserved between cycles.
+
+    // Program counter / Instruction Pointer
+    ip_reg_p ip = ip_reg_create();
+
+    // Register file:
+    reg_p regs = regs_create();
+
+    // Memory:
+    // Shared memory for both instructions and data.
+    mem_p mem = memory_create();
+    memory_read_from_file(mem, argv[1]);
+
+    int start;
+    int scan_res = sscanf(argv[2],"%x", &start);
+    if (scan_res != 1)
+        error("Unable to interpret starting address");
+
+    // We must setup argv from commandline before enabling tracefile
+    // validation.
+    if (argc > 4) { // one or more additional arguments specified.
+        if (strcmp(argv[3],"--") != 0)
+            error("3rd arg must be '--' if additional args are provided");
+        // arguments beyond '--' are loaded into argv area in memory
+        memory_load_argv(mem, argc - 4, argv + 4);
+    } else
+        memory_load_argv(mem, 0, NULL);
+
+    // memory is now set up correctly, and we can enable tracefile
+    // validation if a tracefile has been specified.
+    if (argc == 4) { // tracefile specified, hook memories to it
+        memory_tracefile(mem, argv[3]);
+        regs_tracefile(regs, argv[3]);
+        ip_reg_tracefile(ip, argv[3]);
+    }
+    ip_write(ip, from_int(start), true);
+
+    // a stop signal for stopping the simulation.
+    bool stop = false;
+
+    // We need the instruction number to show how far we get
+    int instruction_number = 0;
+
+    while (!stop) { // SIMULATION BEGINS - for each cycle:
+
+        /*** FETCH ***/
+        val pc = ip_read(ip);
+        ++instruction_number;
+        printf("%d %lx\n", instruction_number, pc.val);
+
+        // We're fetching 10 bytes in the form of 10 vals with one byte each
+        // depending on the instruction we may not use all of them
+        val inst_bytes[10];
+        memory_read_into_buffer(mem, pc, inst_bytes, true);
+
+        /*** DECODE ***/
+        // read 4 bit segments of the instruction. The following 6 segments
+        // are, if present, always located at the same position in the instruction
+        val major_op = pick_bits(4,  4, inst_bytes[0]);
+        val minor_op = pick_bits(0,  4, inst_bytes[0]);
+        val reg_d = pick_bits(4, 4, inst_bytes[1]);
+        val reg_s = pick_bits(0, 4, inst_bytes[1]);
+        val reg_z = pick_bits(4, 4, inst_bytes[2]);
+        val shamt = pick_bits(0, 4, inst_bytes[2]);
+
+        // decode instruction type from major operation code
+        bool is_return_or_stop = is(RETURN_STOP, major_op);
+        bool is_reg_arithmetic = is(REG_ARITHMETIC, major_op);
+        bool is_imm_arithmetic = is(IMM_ARITHMETIC, major_op);
+        bool is_reg_movq = is(REG_MOVQ, major_op);
+        bool is_imm_movq = is(IMM_MOVQ, major_op);
+        bool is_reg_movq_mem = is(REG_MOVQ_MEM, major_op);
+        bool is_imm_movq_mem = is(IMM_MOVQ_MEM, major_op);
+        bool is_cflow = is(CFLOW, major_op); /* note that this signal does not include return - though logically it could */
+        bool is_leaq2  = is(LEAQ2, major_op);
+        bool is_leaq3  = is(LEAQ3, major_op);
+        bool is_leaq6  = is(LEAQ6, major_op);
+        bool is_leaq7  = is(LEAQ7, major_op);
+        bool is_imm_cbranch = is(IMM_CBRANCH, major_op);
+
+        // Right now, we can only execute instructions with a size of 2.
+        // TODO 2021:
+        // from info above determine the instruction size
+        val ins_size = from_int(2); 
+
+        // broad categorization of the instruction
+        bool is_leaq = is_leaq2 || is_leaq3 || is_leaq6 || is_leaq7;
+        bool is_move = is_reg_movq || is_reg_movq_mem || is_imm_movq || is_imm_movq_mem;
+        bool is_mem_access = is_reg_movq_mem || is_imm_movq_mem;
+        bool is_call = is_cflow && is(CALL, minor_op);
+        bool is_return = is_return_or_stop & is(RETURN, minor_op);
+        bool is_stop = is_return_or_stop & is(STOP, minor_op);
+
+        // picking the proper immediate positions within the instruction:
+        bool imm_i_pos3 = is_leaq7;  /* all other at position 2 */
+        bool imm_p_pos6 = is_imm_cbranch; /* all other at position 2 */
+
+        // unimplemented control signals:
+        bool is_load  = false; // TODO 2021: Detect when we're executing a load
+        bool is_store = false; // TODO 2021: Detect when we're executing a store
+        bool is_conditional = false; // TODO 2021: Detect if we are executing a conditional flow change
+
+        // TODO 2021: Add additional control signals you may need below....
+
+        // setting up operand fetch and register read and write for the datapath:
+        bool use_imm = is_imm_movq | is_imm_arithmetic | is_imm_cbranch;
+        val reg_read_dz = or(use_if(!is_leaq, reg_d), use_if(is_leaq, reg_z));
+        // - other read port is always reg_s
+        // - write is always to reg_d
+        bool reg_wr_enable = is_reg_arithmetic || is_imm_arithmetic || is_leaq || is_load || is_reg_movq || is_imm_movq || is_call;
+
+        // control signals for the compute section:
+        // - pick result of compute section
+        bool use_agen = is_leaq || is_move;
+        bool is_arithmetic = is_imm_arithmetic | is_reg_arithmetic;
+        bool use_multiplier = is_arithmetic && (is(MUL, minor_op) || is(IMUL, minor_op));
+        bool use_shifter = is_arithmetic && (is(SAR, minor_op) || is(SAL, minor_op) || is(SHR, minor_op));
+        bool use_direct = is_reg_movq || is_imm_movq;
+        bool use_alu = (is_arithmetic || is_conditional) && !(use_shifter | use_multiplier);
+
+        // - control for agen
+        bool use_s = (is(1,pick_bits(0,1,minor_op)) && use_agen) || is_reg_arithmetic || is_cflow;
+        bool use_z = is(1,pick_bits(1,1,minor_op)) && use_agen;
+        bool use_d = (is(1,pick_bits(2,1,minor_op)) && use_agen) || is_imm_arithmetic || is_imm_cbranch;
+        // - control for the ALU (too easy)
+        val alu_ctrl = minor_op;
+
+        // - control for the multiplier
+        bool mul_is_signed = is(IMUL, minor_op);
+
+        // - control for the shifter
+        bool shft_is_signed = is(SAR, minor_op) | is(SAL, minor_op);
+        bool shft_is_left   = is(SAL, minor_op);
+
+        /*** EXECUTE ***/
+
+        // Datapath:
+        //
+        // read immediates based on instruction type from the instruction buffer
+        val imm_offset_2 = or(or(put_bits(0, 8, inst_bytes[2]), put_bits(8,8, inst_bytes[3])),
+                              or(put_bits(16, 8, inst_bytes[4]), put_bits(24,8, inst_bytes[5])));
+        val imm_offset_3 = or(or(put_bits(0, 8, inst_bytes[3]), put_bits(8,8, inst_bytes[4])),
+                              or(put_bits(16, 8, inst_bytes[5]), put_bits(24,8, inst_bytes[6])));
+        val imm_offset_6 = or(or(put_bits(0, 8, inst_bytes[6]), put_bits(8,8, inst_bytes[7])),
+                              or(put_bits(16, 8, inst_bytes[8]), put_bits(24,8, inst_bytes[9])));
+
+        val imm_i = or(use_if( !imm_i_pos3, imm_offset_2), use_if( imm_i_pos3, imm_offset_3));
+        val imm_p = or(use_if( !imm_p_pos6, imm_offset_2), use_if( imm_p_pos6, imm_offset_6));
+
+        val sext_imm_i = sign_extend(31, imm_i);
+        val sext_imm_p = sign_extend(31, imm_p);
+
+        // read registers
+        val reg_out_a = reg_read(regs, reg_read_dz);
+        val reg_out_b = reg_read(regs, reg_s);
+        val op_b = or(use_if(use_imm, sext_imm_i), use_if(!use_imm, reg_out_b));
+
+        // perform calculations
+        val agen_result = address_generate(reg_out_a, reg_out_b, sext_imm_i,
+                           shamt, use_z, use_s, use_d);
+        val alu_result = alu_execute(alu_ctrl, reg_out_a, op_b);
+        val mul_result = multiplier(mul_is_signed, reg_out_a, op_b);
+        val shifter_result = shifter(shft_is_left, shft_is_signed, reg_out_a, op_b);
+        val compute_result = or(use_if(use_agen, agen_result),
+                    or(use_if(use_multiplier, mul_result),
+                       or(use_if(use_shifter, shifter_result),
+                          or(use_if(use_direct, op_b),
+                         use_if(use_alu, alu_result)))));
+
+        // address of succeeding instruction in memory
+        val pc_incremented  = add(pc, ins_size);
+
+        // determine the next position of the program counter
+        // TODO 2021: Add any additional sources for the next PC (for call, ret, jmp and conditional branch)
+        val pc_next = pc_incremented;
+
+        /*** MEMORY ***/
+        // read from memory if needed
+        val mem_out = memory_read(mem, agen_result, is_load);
+
+        /*** WRITE ***/
+        // choose result to write back to register
+        // TODO 2021: Add any additional results which need to be muxed in for writing to the destination register
+        bool use_compute_result = !is_load && (use_agen || use_multiplier || use_shifter || use_direct || use_alu);
+        val datapath_result = or(use_if(use_compute_result, compute_result),
+                                 use_if(is_load, mem_out));
+
+        // write to register if needed
+        reg_write(regs, reg_d, datapath_result, reg_wr_enable);
+
+        // write to memory if needed
+        memory_write(mem, agen_result, reg_out_a, is_store);
+
+        // update program counter
+        ip_write(ip, pc_next, true);
+
+        // terminate when returning to zero
+        if (is_stop || (pc_next.val == 0 && is_return)) stop = true;
+    }
+    memory_destroy(mem);
+    regs_destroy(regs);
+
+    printf("Done\n");
+}
diff --git a/A5/memory.c b/A5/memory.c
new file mode 100644
index 0000000..7688f4a
--- /dev/null
+++ b/A5/memory.c
@@ -0,0 +1,250 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "memory.h"
+#include "trace_read.h"
+#include "support.h"
+
+#define BLOCK_SIZE 16384
+#define BLOCK_MASK (BLOCK_SIZE - 1)
+
+typedef uint64_t word;
+typedef uint8_t byte;
+
+struct block {
+    word start_addr;
+    byte* data;
+};
+
+struct memory {
+    struct block* blocks;
+    int num_blocks;
+    trace_p m_tracer;
+    trace_p i_tracer;
+    trace_p o_tracer;
+};
+
+mem_p memory_create() {
+    mem_p res = (mem_p) malloc(sizeof(struct memory));
+    res->num_blocks = 0;
+    res->blocks = 0;
+    res->m_tracer = 0;
+    return res;
+}
+
+void memory_destroy(mem_p mem) {
+    for (int i = 0; i < mem->num_blocks; ++i) {
+        free(mem->blocks[i].data);
+    }
+    free(mem->blocks);
+    if (mem->m_tracer) {
+        if (!trace_all_matched(mem->m_tracer))
+            error("Parts of trace for memory writes was not matched");
+        trace_reader_destroy(mem->m_tracer);
+    }
+    if (mem->i_tracer) {
+        if (!trace_all_matched(mem->i_tracer))
+            error("Parts of trace for input was not matched");
+        trace_reader_destroy(mem->i_tracer);
+    }
+    if (mem->o_tracer) {
+        if (!trace_all_matched(mem->o_tracer))
+            error("Parts of trace for output was not matched");
+        trace_reader_destroy(mem->o_tracer);
+    }
+    free(mem);
+}
+
+void memory_tracefile(mem_p mem, const char* filename) {
+    mem->m_tracer = trace_reader_create('M', filename);
+    mem->i_tracer = trace_reader_create('I', filename);
+    mem->o_tracer = trace_reader_create('O', filename);
+}
+
+struct block* get_block(mem_p mem, word start_addr) {
+    struct block* bp = 0;
+    for (int i = 0; i < mem->num_blocks; ++i) {
+        if (mem->blocks[i].start_addr == start_addr) {
+            bp = &mem->blocks[i];
+            break;
+        }
+    }
+    if (bp == 0) {
+        mem->blocks = realloc(mem->blocks, (mem->num_blocks + 1) * sizeof(struct block));
+        mem->blocks[mem->num_blocks].data = malloc(sizeof(unsigned char) * BLOCK_SIZE);
+        mem->blocks[mem->num_blocks].start_addr = start_addr;
+        bp = &mem->blocks[mem->num_blocks];
+        mem->num_blocks++;
+    }
+    return bp;
+}
+
+/* uses byte addresses */
+word memory_read_byte(mem_p mem, word byte_addr) {
+    word byte_number = byte_addr & BLOCK_MASK;
+    word block_addr = byte_addr - byte_number;
+    struct block* bp = get_block(mem, block_addr);
+    return bp->data[byte_number];
+}
+
+void memory_write_byte(mem_p mem, word byte_addr, word byte) {
+    word byte_number = byte_addr & BLOCK_MASK;
+    word block_addr = byte_addr - byte_number;
+    struct block* bp = get_block(mem, block_addr);
+    bp->data[byte_number] = byte;
+}
+
+word memory_read_quad(mem_p mem, word byte_addr) {
+    word res = memory_read_byte(mem, byte_addr++);
+    res = res | (memory_read_byte(mem, byte_addr++) << 8);
+    res = res | (memory_read_byte(mem, byte_addr++) << 16);
+    res = res | (memory_read_byte(mem, byte_addr++) << 24);
+    res = res | (memory_read_byte(mem, byte_addr++) << 32);
+    res = res | (memory_read_byte(mem, byte_addr++) << 40);
+    res = res | (memory_read_byte(mem, byte_addr++) << 48);
+    res = res | (memory_read_byte(mem, byte_addr++) << 56);
+    return res;
+}
+
+void memory_write_quad(mem_p mem, word byte_addr, word value) {
+    memory_write_byte(mem, byte_addr++, value); value >>= 8;
+    memory_write_byte(mem, byte_addr++, value); value >>= 8;
+    memory_write_byte(mem, byte_addr++, value); value >>= 8;
+    memory_write_byte(mem, byte_addr++, value); value >>= 8;
+    memory_write_byte(mem, byte_addr++, value); value >>= 8;
+    memory_write_byte(mem, byte_addr++, value); value >>= 8;
+    memory_write_byte(mem, byte_addr++, value); value >>= 8;
+    memory_write_byte(mem, byte_addr++, value); value >>= 8;
+}
+
+
+void error(const char*);
+
+void memory_read_from_file(mem_p mem, const char* filename) {
+    FILE* f = fopen(filename, "r");
+    if (f == NULL) {
+	error("Failed to open file");
+    }
+    int res;
+    do {
+        word addr;
+        char buf[21]; // most we'll need, plus terminating 0
+        res = fscanf(f, "%lx : ", &addr);
+        if (res != EOF) {
+            res = fscanf(f, " %[0123456789ABCDEFabcdef]", buf);
+            if (res == 1) {
+                //printf("%lx : %s\n", addr, buf);
+                char* p = buf;
+                while (*p != 0) {
+                    // convert byte by byte (= 2 char at a time)
+                    char buf2[3];
+                    buf2[0] = *p++;
+                    buf2[1] = *p++;
+                    buf2[2] = 0;
+                    int byte_from_hex;
+                    sscanf(buf2, "%x", &byte_from_hex);
+                    memory_write_byte(mem, addr, byte_from_hex);
+                    int check = memory_read_byte(mem, addr);
+                    if (check != byte_from_hex)
+                      printf("Memory error: at %lx, wrote %x, read back %x\n", addr, byte_from_hex, check);
+                    addr++;
+                }
+            }
+            // fscanf(f,"#");
+            while ('\n' != getc(f));
+        }
+    } while (res != EOF);
+    fclose(f);
+}
+
+// read 10 bytes from memory, unaligned, uses byte addressing
+void memory_read_into_buffer(mem_p mem, val address, val bytes[], bool enable) {
+    word addr = address.val;
+    for (int i = 0; i < 10; ++i) {
+        if (enable)
+            bytes[i] = from_int(memory_read_byte(mem, addr + i));
+        else
+            bytes[i] = from_int(0);
+    }
+}
+
+bool is_io_device(val address) {
+    return address.val >= 0x10000000 && address.val < 0x20000000;
+}
+
+bool is_argv_area(val address) {
+    return address.val >= 0x20000000 && address.val < 0x30000000;
+}
+
+val memory_read(mem_p mem, val address, bool enable) {
+    if (!enable) return from_int(0);
+    if (is_io_device(address)) {
+        val retval;
+        if (mem->i_tracer) {
+            if (trace_match_and_get_next(mem->i_tracer, address, &retval))
+                return retval;
+            else
+                error("Trace mismatch on input from device");
+        }
+        if (address.val == 0x10000000) {
+          int status;
+          status = scanf("%lx", &retval.val);
+          (void)status; // silence warning - we should perhaps one day check this?
+        }
+        else if (address.val == 0x10000001) retval.val = rand();
+        else error("Input from unknown port");
+        return retval;
+    }
+    else if (is_argv_area(address)) {
+        val retval;
+        if (mem->i_tracer) {
+            if (trace_match_and_get_next(mem->i_tracer, address, &retval))
+                return retval;
+            else
+                error("Trace mismatch on read from argv area");
+        }
+        // if no tracer, just access arguments from memory. Presumably set from commandline
+        return from_int(memory_read_quad(mem, address.val));
+    }
+    else {
+        return from_int(memory_read_quad(mem, address.val));
+    }
+}
+
+void memory_write(mem_p mem, val address, val value, bool wr_enable) {
+    if (wr_enable) {
+        if (is_io_device(address)) {
+            if (mem->o_tracer) {
+                if (trace_match_next(mem->o_tracer, address, value))
+                    return;
+                else
+                    error("Trace mismatch on output to device");
+            }
+            if (address.val == 0x10000002) printf("%lx ", value.val);
+            else error("Output to unknown port");
+        } else {
+            // With respect to writes, we treat the argv area as a normal memory area
+            if (trace_match_next(mem->m_tracer, address, value))
+                memory_write_quad(mem, address.val, value.val);
+            else
+                error("Trace mismatch on write to memory");
+        }
+    }
+}
+
+void memory_load_argv(mem_p mem, int argc, char* argv[]) {
+    val address;
+    address.val = 0x20000000;
+    val value;
+    value.val = argc;
+    memory_write(mem, address, value, true);
+    for (int k = 0; k < argc; ++k) {
+        int v;
+        int res = sscanf(argv[k],"%d", &v);
+        if (res != 1)
+            error("Invalid command line argument");
+        address.val += 8;
+        value.val = v;
+        memory_write(mem, address, value, true);
+    }
+}
diff --git a/A5/memory.h b/A5/memory.h
new file mode 100644
index 0000000..28628c2
--- /dev/null
+++ b/A5/memory.h
@@ -0,0 +1,38 @@
+/*
+  Memory elements and IO devices
+
+  Memory resizes dynamically to accomodate usage.
+  IO Devices are located at addresses 0x1000000000 to 0x1FFFFFFF.
+  Three devices are implemented:
+  0x10000000 Input quadword from standard input
+  0x10000001 Input pseudo-random quadword
+  0x00000002 Output quadword to standard output
+*/
+
+#include "wires.h"
+
+struct memory;
+typedef struct memory *mem_p;
+
+mem_p memory_create();
+void memory_destroy(mem_p);
+void memory_read_from_file(mem_p, const char* filename);
+
+// set a tracefile for validation of memory writes and input/output
+void memory_tracefile(mem_p mem, const char* filename);
+
+// Read quadword. We use little endian byte-addressing and support unaligned access
+// If the address is to an input device, input will be performed instead of memory access
+val memory_read(mem_p, val address, bool enable);
+
+// Write quadword with new value at rising edge of clock.
+// There are no internal forwarding from write to read in same clock period
+// Little endian byte-addressing and unaligned access is supported
+// If the address is to an output device, output will be performed instead of memory access
+void memory_write(mem_p, val address, val value, bool wr_enable);
+
+// read 10 bytes unaligned, for instruction fetch
+void memory_read_into_buffer(mem_p, val address, val bytes[], bool enable);
+
+// parse argument vector and load it into simulated argv area
+void memory_load_argv(mem_p, int argc, char* argv[]);
diff --git a/A5/registers.c b/A5/registers.c
new file mode 100644
index 0000000..33b3607
--- /dev/null
+++ b/A5/registers.c
@@ -0,0 +1,49 @@
+/*
+  Implementation of x86prime 16 registers
+*/
+
+#include "registers.h"
+#include "support.h"
+#include "trace_read.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+
+struct registers {
+    trace_p tracer;
+    val data[16];
+};
+
+reg_p regs_create() {
+    reg_p regs = (reg_p) malloc(sizeof(struct registers));
+    for (int i = 0; i < 16; ++i)
+        regs->data[i] = from_int(0);
+    regs->tracer = 0;
+    return regs;
+}
+
+void regs_destroy(reg_p regs) {
+    if (regs->tracer) {
+        if (!trace_all_matched(regs->tracer))
+            error("Parts of trace for register writes was not matched");
+        trace_reader_destroy(regs->tracer);
+    }
+    free(regs);
+}
+
+void regs_tracefile(reg_p regs, const char *filename) {
+    regs->tracer = trace_reader_create('R', filename);
+}
+
+val reg_read(reg_p regs, val reg_num) {
+    return regs->data[reg_num.val & 0x0F];
+}
+
+void reg_write(reg_p regs, val reg_num, val value, bool wr_enable) {
+    if (wr_enable) {
+        if (trace_match_next(regs->tracer, reg_num, value))
+            regs->data[reg_num.val & 0x0F] = value;
+        else
+            error("Trace mismatch on write to register");
+    }
+}
diff --git a/A5/registers.h b/A5/registers.h
new file mode 100644
index 0000000..260d18a
--- /dev/null
+++ b/A5/registers.h
@@ -0,0 +1,19 @@
+/*
+  Registers
+
+  A model of the 16 registers in x86prime
+*/
+
+#include "wires.h"
+
+struct registers;
+typedef struct registers *reg_p;
+
+reg_p regs_create();
+void regs_destroy(reg_p);
+
+// associate with a tracefile for verification
+void regs_tracefile(reg_p regs, const char *filename);
+
+val reg_read(reg_p regs, val reg_num);
+void reg_write(reg_p regs, val reg_num, val value, bool wr_enable);
diff --git a/A5/support.c b/A5/support.c
new file mode 100644
index 0000000..db82501
--- /dev/null
+++ b/A5/support.c
@@ -0,0 +1,9 @@
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "support.h"
+
+void error(const char* message) {
+    fprintf(stderr, "%s\n", message);
+    exit(-1);
+}
diff --git a/A5/support.h b/A5/support.h
new file mode 100644
index 0000000..4f15aa6
--- /dev/null
+++ b/A5/support.h
@@ -0,0 +1,7 @@
+/*
+  Support functions. Just one for now.
+*/
+
+// print an error and exit
+void error(const char* message);
+
diff --git a/A5/test.sh b/A5/test.sh
new file mode 100755
index 0000000..a2781e3
--- /dev/null
+++ b/A5/test.sh
@@ -0,0 +1,67 @@
+#!/bin/bash
+
+### USAGE
+# All test must x86prime files (*.prime), located in tests
+# All test must start with a label "test:" from which the test start
+#   You can insert a "jmp myprogram" as the first instruction, if your program starts elsewhere
+
+# Exit immediately if any command below fails.
+set -e
+
+# Ensure latest version
+make
+
+# The command with which you run PRUN: You should likely change this variable
+PRUN=prun
+
+# The command with which you run PRASM: You should likely change this variable
+PRASM=prasm
+
+TESTLOC=tests
+TESTDIR=test_runs
+
+if [[ ! -d "${TESTLOC}" ]] ; then
+  echo "Cannot find the test location ${TESTLOC}"
+  exit
+fi
+
+echo ">> I will now test all *.prime files in ${TESTLOC}/"
+
+echo "Generating a test_runs directory.."
+mkdir -p $TESTDIR
+rm -f $TESTDIR/*
+
+echo "Running the tests.."
+exitcode=0
+
+for f in tests/*.prime; do
+  filename=${f#"$TESTLOC/"}
+  fname=${filename%.prime}
+
+  echo ">>> Testing ${filename}.."
+
+  # Generate hex file
+  hexfile=$TESTDIR/$fname.hex
+  $PRASM $f
+  mv $TESTLOC/$fname.hex $TESTDIR/
+  mv $TESTLOC/$fname.sym $TESTDIR/
+
+  # Generate trace file
+  tracefile=$TESTDIR/$fname.trc
+  $PRUN $hexfile test -tracefile $tracefile
+
+  set +e # Continue after failed trace
+  ./sim $hexfile 0x0 $tracefile > $TESTDIR/$fname.out
+  set -e
+
+  if [ ! $(grep Done $TESTDIR/$fname.out) ]
+  then
+    echo "Failed :-("
+    echo "For details, see $TESTDIR/$fname.out"
+    exitcode=1
+  else
+    echo "Success :-)"
+  fi
+done
+
+exit $exitcode
diff --git a/A5/trace_read.c b/A5/trace_read.c
new file mode 100644
index 0000000..36aedd0
--- /dev/null
+++ b/A5/trace_read.c
@@ -0,0 +1,99 @@
+/*
+  Trace reader implementation
+*/
+
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "support.h"
+#include "trace_read.h"
+
+typedef uint64_t word;
+
+struct trace_reader  {
+    FILE* trace_file;
+    char filter;
+    bool next_valid;
+    word next_addr;
+    word next_value;
+};
+
+
+trace_p trace_reader_create(char filter, const char* filename) {
+    FILE* f = fopen(filename, "r");
+    if (f == NULL)
+        error("Failed to open tracefile");
+    trace_p tracer = malloc(sizeof(struct trace_reader));
+    tracer->trace_file = f;
+    tracer->filter = filter;
+    tracer->next_valid = false;
+    return tracer;
+}
+
+void trace_reader_destroy(trace_p tracer) {
+    fclose(tracer->trace_file);
+    free(tracer);
+}
+
+void get_next_if_needed_and_possible(trace_p tracer) {
+    if (tracer->next_valid) return; /* no need */
+    int domain;
+    do {
+        domain = getc(tracer->trace_file); /* every line starts with the domain */
+        if (domain == EOF) return; /* trace ended */
+        int res = fscanf(tracer->trace_file, " %lx %lx ", &tracer->next_addr, &tracer->next_value);
+        if (res != 2)
+            error("Wrong trace format"); /* couldn't read the entry??? */
+    } while (domain != tracer->filter); /* skip other domains */
+    tracer->next_valid = true;
+}
+
+bool trace_match_next(trace_p tracer, val address, val value) {
+    if (tracer == 0) return true; // no trace file - condition trivially true
+    get_next_if_needed_and_possible(tracer);
+    if (!tracer->next_valid) {
+        printf(" -- end of tracefile reached, while trying to match '%c' %lx <- %lx\n", 
+               tracer->filter, address.val, value.val);
+        return false;
+    }
+    if (tracer->next_addr != address.val) {
+        printf(" -- address mismatch, access '%c' %lx, but tracefile expected address: %lx\n", 
+               tracer->filter, address.val, tracer->next_addr);
+        return false;
+    }
+    if (tracer->next_value != value.val) {
+        printf(" -- value mismatch, access '%c' %lx\n", tracer->filter, address.val);
+        printf(" -- with value %lx, but tracefile expected %lx\n", value.val, tracer->next_value);
+        return false;
+    }
+    /* matched! */
+    tracer->next_valid = false; /* we just matched it */
+    return true;
+}
+
+bool trace_match_and_get_next(trace_p tracer, val address, val* value) {
+    if (tracer == 0) return true; // no trace file
+    get_next_if_needed_and_possible(tracer);
+    if (!tracer->next_valid) {
+        printf(" -- end of tracefile reached, while trying to match '%c' %lx <- <<some value>>\n", 
+               tracer->filter, address.val);
+        return false;
+    }
+    if (tracer->next_addr != address.val) {
+        printf(" -- address mismatch, access '%c' %lx, but tracefile expected address: %lx\n", 
+               tracer->filter, address.val, tracer->next_addr);
+        return false;
+    }
+    value->val = tracer->next_value;
+    tracer->next_valid = false;
+    return true;
+}
+
+
+bool trace_all_matched(trace_p tracer) {
+    if (tracer == 0) return true; // no trace file - condition trivially true
+    get_next_if_needed_and_possible(tracer);
+    return !tracer->next_valid;
+}
+
diff --git a/A5/trace_read.h b/A5/trace_read.h
new file mode 100644
index 0000000..c80b1ba
--- /dev/null
+++ b/A5/trace_read.h
@@ -0,0 +1,17 @@
+/*
+  trace reader. Used by memories to validate changes against a trace built by x86prime
+*/
+
+#include "wires.h"
+
+struct trace_reader;
+
+typedef struct trace_reader *trace_p;
+
+trace_p trace_reader_create(char filter, const char* filename);
+void trace_reader_destroy(trace_p tracer);
+
+bool trace_match_next(trace_p tracer, val address, val value); // true if matched
+bool trace_match_and_get_next(trace_p tracer, val address, val* value); // true if matched AND enabled
+
+bool trace_all_matched(trace_p tracer);
diff --git a/A5/wires.c b/A5/wires.c
new file mode 100644
index 0000000..7a156b2
--- /dev/null
+++ b/A5/wires.c
@@ -0,0 +1,98 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include "wires.h"
+
+hilo unzip(val value) {
+    uint64_t hi, lo, val;
+    val = value.val;
+    hi = lo = 0;
+    for (int i=0; i<32; i++) {
+	lo |= (val & 1) << i;
+	val >>= 1;
+	hi |= (val & 1) << i;
+	val >>= 1;
+    }
+    hilo result;
+    result.hi = from_int(hi);
+    result.lo = from_int(lo);
+    return result;
+}
+
+val zip(hilo values) {
+    uint64_t hi = values.hi.val;
+    uint64_t lo = values.lo.val;
+    uint64_t result = 0;
+    for (int i=0; i<32; i++) {
+	result |= (hi & 1) << (2*i+1);
+	hi >>= 1;
+	result |= (lo & 1) << (2*i);
+	lo >>= 1;
+    }
+    return from_int(result);
+}
+
+val pick_bits(int lsb, int sz, val value) {
+    uint64_t v = value.val;
+    v >>= lsb;
+    if (sz < 64) {
+        uint64_t mask = 1;
+        mask <<= sz;
+        mask -= 1;
+        v &= mask;
+    }
+    return from_int(v);
+}
+
+val put_bits(int lsb, int sz, val value) {
+    val masked = pick_bits(0,sz,value);
+    masked.val <<= lsb;
+    return masked;
+}
+
+val pick_bits_arr(int msb, int sz, val arr[]) {
+    if (sz > 64) {
+        fprintf(stderr, "error: pick_bits_arr called with sz > 64");
+        exit(EXIT_FAILURE);
+    }
+
+    int offset = msb % 8;
+    int start_byte = msb / 8;
+    int covered_bytes = sz / 8;
+
+    uint64_t retval = 0;
+    for(int i = start_byte; i < covered_bytes; i++) {
+        retval += ((uint64_t) (arr[i].val)) >> (offset + i * 8);
+    }
+
+    uint64_t mask = ((uint64_t)-1) >> (64 - offset);
+    retval &= mask;
+    return from_int(retval);
+}
+
+
+bool pick_one(int position, val value) {
+  return ((value.val >> position) & 1) == 1;
+}
+
+val from_int(uint64_t v) {
+    val val;
+    val.val = v;
+    return val;
+}
+
+val reverse_bytes(int num_bytes, val value) {
+    uint64_t val = value.val;
+    uint64_t res = 0;
+    while (num_bytes--) {
+        res <<= 8;
+        res |= val & 0xFF;
+        val >>= 8;
+    }
+    return from_int(res);
+}
+
+val sign_extend(int sign_position, val value) {
+    uint64_t sign = value.val & (((uint64_t)1) << sign_position);
+    return from_int(value.val - (sign << 1));
+}
+
diff --git a/A5/wires.h b/A5/wires.h
new file mode 100644
index 0000000..cd8591e
--- /dev/null
+++ b/A5/wires.h
@@ -0,0 +1,56 @@
+/*
+  Elementary functions for digital logic simulation
+
+  All functions declared here corresponds to wire connections.
+  No "real" computation is being carried out by them.
+
+  A single wire, when used as a control signal, is represented by the type 'bool'
+  Multiple wires, or a single wire not used as a control signal, is represented
+  by the type 'val'
+
+  For control signals (bools) you can use C built-in operators.
+*/
+
+#ifndef WIRES_H
+#define WIRES_H
+
+#include <inttypes.h>
+#include <stdbool.h>
+
+// A generic bitvector - max 64 bits, though. By accident sufficient for our needs :-)
+typedef struct { uint64_t val; } val;
+
+// A pair of bitvectors - used by zip() and unzip()
+typedef struct {
+    val hi;
+    val lo;
+} hilo;
+
+// simple conversion
+val from_int(uint64_t);
+
+// unzip pairwise into two bitvectors holding even/odd bits
+hilo unzip(val);
+
+// zip a pair of bitvectors into one.
+val zip(hilo);
+
+// pick a set of bits from a value
+// lsb: index of least significant bit
+// sz: size
+val pick_bits(int lsb, int sz, val);
+
+// put sz least significant bits from val at position lsb in result.
+// rest of result is 0.
+val put_bits(int lsb, int sz, val);
+
+// pick a single bit from a value
+bool pick_one(int position, val);
+
+// reverse the order of bytes within value
+val reverse_bytes(int num_bytes, val value);
+
+// sign extend by copying a sign bit to all higher positions
+val sign_extend(int sign_position, val value);
+
+#endif