diff --git a/README.md b/README.md
index ba670b7..dba667b 100644
--- a/README.md
+++ b/README.md
@@ -1,14 +1,20 @@
-c4 - C in four functions
-========================
-
+c5 - C in four functions + AST + back-end code generator
+========================================================
 An exercise in minimalism.
 
+This branch extends **c4.c** by adding:
+
+   * Abstract Syntax Tree creation
+   * Back-end code generator function: **gen()**
+   * Standard ordering of function parameters on stack
+   * Native x86 version: **c5x86.c**
+   * Various optimizations
+  
 Try the following:
 
-    gcc -o c4 c4.c  (you may need the -m32 option on 64bit machines)
-    ./c4 hello.c
-    ./c4 -s hello.c
+    gcc -o c5 c5.c  (you may need the -m32 option on 64bit machines)
+    ./c5 hello.c
+    ./c5 -s hello.c
     
-    ./c4 c4.c hello.c
-    ./c4 c4.c c4.c hello.c
-
+    ./c5 c5.c hello.c
+    ./c5 c5.c c5.c hello.c
diff --git a/c4.c b/c4.c
deleted file mode 100644
index bebeec1..0000000
--- a/c4.c
+++ /dev/null
@@ -1,525 +0,0 @@
-// c4.c - C in four functions
-
-// char, int, and pointer types
-// if, while, return, and expression statements
-// just enough features to allow self-compilation and a bit more
-
-// Written by Robert Swierczek
-
-#include <stdio.h>
-#include <stdlib.h>
-#include <memory.h>
-#include <unistd.h>
-
-char *p, *lp, // current position in source code
-     *data;   // data/bss pointer
-
-int *e, *le,  // current position in emitted code
-    *id,      // currently parsed identifier
-    *sym,     // symbol table (simple list of identifiers)
-    tk,       // current token
-    ival,     // current token value
-    ty,       // current expression type
-    loc,      // local variable offset
-    line,     // current line number
-    src,      // print source and assembly flag
-    debug;    // print executed instructions
-
-// tokens and classes (operators last and in precedence order)
-enum {
-  Num = 128, Fun, Sys, Glo, Loc, Id,
-  Char, Else, Enum, If, Int, Return, Sizeof, While,
-  Assign, Cond, Lor, Lan, Or, Xor, And, Eq, Ne, Lt, Gt, Le, Ge, Shl, Shr, Add, Sub, Mul, Div, Mod, Inc, Dec, Brak
-};
-
-// opcodes
-enum { LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,
-       OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,
-       OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,EXIT };
-
-// types
-enum { CHAR, INT, PTR };
-
-// identifier offsets (since we can't create an ident struct)
-enum { Tk, Hash, Name, Class, Type, Val, HClass, HType, HVal, Idsz };
-
-void next()
-{
-  char *pp;
-
-  while (tk = *p) {
-    ++p;
-    if (tk == '\n') {
-      if (src) {
-        printf("%d: %.*s", line, p - lp, lp);
-        lp = p;
-        while (le < e) {
-          printf("%8.4s", &"LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,"
-                           "OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,"
-                           "OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,EXIT,"[*++le * 5]);
-          if (*le <= ADJ) printf(" %d\n", *++le); else printf("\n");
-        }
-      }
-      ++line;
-    }
-    else if (tk == '#') {
-      while (*p != 0 && *p != '\n') ++p;
-    }
-    else if ((tk >= 'a' && tk <= 'z') || (tk >= 'A' && tk <= 'Z') || tk == '_') {
-      pp = p - 1;
-      while ((*p >= 'a' && *p <= 'z') || (*p >= 'A' && *p <= 'Z') || (*p >= '0' && *p <= '9') || *p == '_')
-        tk = tk * 147 + *p++;
-      tk = (tk << 6) + (p - pp);
-      id = sym;
-      while (id[Tk]) {
-        if (tk == id[Hash] && !memcmp((char *)id[Name], pp, p - pp)) { tk = id[Tk]; return; }
-        id = id + Idsz;
-      }
-      id[Name] = (int)pp;
-      id[Hash] = tk;
-      tk = id[Tk] = Id;
-      return;
-    }
-    else if (tk >= '0' && tk <= '9') {
-      if (ival = tk - '0') { while (*p >= '0' && *p <= '9') ival = ival * 10 + *p++ - '0'; }
-      else if (*p == 'x' || *p == 'X') {
-        while ((tk = *++p) && ((tk >= '0' && tk <= '9') || (tk >= 'a' && tk <= 'f') || (tk >= 'A' && tk <= 'F')))
-          ival = ival * 16 + (tk & 15) + (tk >= 'A' ? 9 : 0);
-      }
-      else { while (*p >= '0' && *p <= '7') ival = ival * 8 + *p++ - '0'; }
-      tk = Num;
-      return;
-    }
-    else if (tk == '/') {
-      if (*p == '/') {
-        ++p;
-        while (*p != 0 && *p != '\n') ++p;
-      }
-      else {
-        tk = Div;
-        return;
-      }
-    }
-    else if (tk == '\'' || tk == '"') {
-      pp = data;
-      while (*p != 0 && *p != tk) {
-        if ((ival = *p++) == '\\') {
-          if ((ival = *p++) == 'n') ival = '\n';
-        }
-        if (tk == '"') *data++ = ival;
-      }
-      ++p;
-      if (tk == '"') ival = (int)pp; else tk = Num;
-      return;
-    }
-    else if (tk == '=') { if (*p == '=') { ++p; tk = Eq; } else tk = Assign; return; }
-    else if (tk == '+') { if (*p == '+') { ++p; tk = Inc; } else tk = Add; return; }
-    else if (tk == '-') { if (*p == '-') { ++p; tk = Dec; } else tk = Sub; return; }
-    else if (tk == '!') { if (*p == '=') { ++p; tk = Ne; } return; }
-    else if (tk == '<') { if (*p == '=') { ++p; tk = Le; } else if (*p == '<') { ++p; tk = Shl; } else tk = Lt; return; }
-    else if (tk == '>') { if (*p == '=') { ++p; tk = Ge; } else if (*p == '>') { ++p; tk = Shr; } else tk = Gt; return; }
-    else if (tk == '|') { if (*p == '|') { ++p; tk = Lor; } else tk = Or; return; }
-    else if (tk == '&') { if (*p == '&') { ++p; tk = Lan; } else tk = And; return; }
-    else if (tk == '^') { tk = Xor; return; }
-    else if (tk == '%') { tk = Mod; return; }
-    else if (tk == '*') { tk = Mul; return; }
-    else if (tk == '[') { tk = Brak; return; }
-    else if (tk == '?') { tk = Cond; return; }
-    else if (tk == '~' || tk == ';' || tk == '{' || tk == '}' || tk == '(' || tk == ')' || tk == ']' || tk == ',' || tk == ':') return;
-  }
-}
-
-void expr(int lev)
-{
-  int t, *d;
-
-  if (!tk) { printf("%d: unexpected eof in expression\n", line); exit(-1); }
-  else if (tk == Num) { *++e = IMM; *++e = ival; next(); ty = INT; }
-  else if (tk == '"') {
-    *++e = IMM; *++e = ival; next();
-    while (tk == '"') next();
-    data = (char *)((int)data + sizeof(int) & -sizeof(int)); ty = PTR;
-  }
-  else if (tk == Sizeof) {
-    next(); if (tk == '(') next(); else { printf("%d: open paren expected in sizeof\n", line); exit(-1); }
-    ty = INT; if (tk == Int) next(); else if (tk == Char) { next(); ty = CHAR; }
-    while (tk == Mul) { next(); ty = ty + PTR; }
-    if (tk == ')') next(); else { printf("%d: close paren expected in sizeof\n", line); exit(-1); }
-    *++e = IMM; *++e = (ty == CHAR) ? sizeof(char) : sizeof(int);
-    ty = INT;
-  }
-  else if (tk == Id) {
-    d = id; next();
-    if (tk == '(') {
-      next();
-      t = 0;
-      while (tk != ')') { expr(Assign); *++e = PSH; ++t; if (tk == ',') next(); }
-      next();
-      if (d[Class] == Sys) *++e = d[Val];
-      else if (d[Class] == Fun) { *++e = JSR; *++e = d[Val]; }
-      else { printf("%d: bad function call\n", line); exit(-1); }
-      if (t) { *++e = ADJ; *++e = t; }
-      ty = d[Type];
-    }
-    else if (d[Class] == Num) { *++e = IMM; *++e = d[Val]; ty = INT; }
-    else {
-      if (d[Class] == Loc) { *++e = LEA; *++e = loc - d[Val]; }
-      else if (d[Class] == Glo) { *++e = IMM; *++e = d[Val]; }
-      else { printf("%d: undefined variable\n", line); exit(-1); }
-      *++e = ((ty = d[Type]) == CHAR) ? LC : LI;
-    }
-  }
-  else if (tk == '(') {
-    next();
-    if (tk == Int || tk == Char) {
-      t = (tk == Int) ? INT : CHAR; next();
-      while (tk == Mul) { next(); t = t + PTR; }
-      if (tk == ')') next(); else { printf("%d: bad cast\n", line); exit(-1); }
-      expr(Inc);
-      ty = t;
-    }
-    else {
-      expr(Assign);
-      if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
-    }
-  }
-  else if (tk == Mul) {
-    next(); expr(Inc);
-    if (ty > INT) ty = ty - PTR; else { printf("%d: bad dereference\n", line); exit(-1); }
-    *++e = (ty == CHAR) ? LC : LI;
-  }
-  else if (tk == And) {
-    next(); expr(Inc);
-    if (*e == LC || *e == LI) --e; else { printf("%d: bad address-of\n", line); exit(-1); }
-    ty = ty + PTR;
-  }
-  else if (tk == '!') { next(); expr(Inc); *++e = PSH; *++e = IMM; *++e = 0; *++e = EQ; ty = INT; }
-  else if (tk == '~') { next(); expr(Inc); *++e = PSH; *++e = IMM; *++e = -1; *++e = XOR; ty = INT; }
-  else if (tk == Add) { next(); expr(Inc); ty = INT; }
-  else if (tk == Sub) {
-    next(); *++e = IMM;
-    if (tk == Num) { *++e = -ival; next(); } else { *++e = -1; *++e = PSH; expr(Inc); *++e = MUL; }
-    ty = INT;
-  }
-  else if (tk == Inc || tk == Dec) {
-    t = tk; next(); expr(Inc);
-    if (*e == LC) { *e = PSH; *++e = LC; }
-    else if (*e == LI) { *e = PSH; *++e = LI; }
-    else { printf("%d: bad lvalue in pre-increment\n", line); exit(-1); }
-    *++e = PSH;
-    *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
-    *++e = (t == Inc) ? ADD : SUB;
-    *++e = (ty == CHAR) ? SC : SI;
-  }
-  else { printf("%d: bad expression\n", line); exit(-1); }
-
-  while (tk >= lev) { // "precedence climbing" or "Top Down Operator Precedence" method
-    t = ty;
-    if (tk == Assign) {
-      next();
-      if (*e == LC || *e == LI) *e = PSH; else { printf("%d: bad lvalue in assignment\n", line); exit(-1); }
-      expr(Assign); *++e = ((ty = t) == CHAR) ? SC : SI;
-    }
-    else if (tk == Cond) {
-      next();
-      *++e = BZ; d = ++e;
-      expr(Assign);
-      if (tk == ':') next(); else { printf("%d: conditional missing colon\n", line); exit(-1); }
-      *d = (int)(e + 3); *++e = JMP; d = ++e;
-      expr(Cond);
-      *d = (int)(e + 1);
-    }
-    else if (tk == Lor) { next(); *++e = BNZ; d = ++e; expr(Lan); *d = (int)(e + 1); ty = INT; }
-    else if (tk == Lan) { next(); *++e = BZ;  d = ++e; expr(Or);  *d = (int)(e + 1); ty = INT; }
-    else if (tk == Or)  { next(); *++e = PSH; expr(Xor); *++e = OR;  ty = INT; }
-    else if (tk == Xor) { next(); *++e = PSH; expr(And); *++e = XOR; ty = INT; }
-    else if (tk == And) { next(); *++e = PSH; expr(Eq);  *++e = AND; ty = INT; }
-    else if (tk == Eq)  { next(); *++e = PSH; expr(Lt);  *++e = EQ;  ty = INT; }
-    else if (tk == Ne)  { next(); *++e = PSH; expr(Lt);  *++e = NE;  ty = INT; }
-    else if (tk == Lt)  { next(); *++e = PSH; expr(Shl); *++e = LT;  ty = INT; }
-    else if (tk == Gt)  { next(); *++e = PSH; expr(Shl); *++e = GT;  ty = INT; }
-    else if (tk == Le)  { next(); *++e = PSH; expr(Shl); *++e = LE;  ty = INT; }
-    else if (tk == Ge)  { next(); *++e = PSH; expr(Shl); *++e = GE;  ty = INT; }
-    else if (tk == Shl) { next(); *++e = PSH; expr(Add); *++e = SHL; ty = INT; }
-    else if (tk == Shr) { next(); *++e = PSH; expr(Add); *++e = SHR; ty = INT; }
-    else if (tk == Add) {
-      next(); *++e = PSH; expr(Mul);
-      if ((ty = t) > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL;  }
-      *++e = ADD;
-    }
-    else if (tk == Sub) {
-      next(); *++e = PSH; expr(Mul);
-      if (t > PTR && t == ty) { *++e = SUB; *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = DIV; ty = INT; }
-      else if ((ty = t) > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL; *++e = SUB; }
-      else *++e = SUB;
-    }
-    else if (tk == Mul) { next(); *++e = PSH; expr(Inc); *++e = MUL; ty = INT; }
-    else if (tk == Div) { next(); *++e = PSH; expr(Inc); *++e = DIV; ty = INT; }
-    else if (tk == Mod) { next(); *++e = PSH; expr(Inc); *++e = MOD; ty = INT; }
-    else if (tk == Inc || tk == Dec) {
-      if (*e == LC) { *e = PSH; *++e = LC; }
-      else if (*e == LI) { *e = PSH; *++e = LI; }
-      else { printf("%d: bad lvalue in post-increment\n", line); exit(-1); }
-      *++e = PSH; *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
-      *++e = (tk == Inc) ? ADD : SUB;
-      *++e = (ty == CHAR) ? SC : SI;
-      *++e = PSH; *++e = IMM; *++e = (ty > PTR) ? sizeof(int) : sizeof(char);
-      *++e = (tk == Inc) ? SUB : ADD;
-      next();
-    }
-    else if (tk == Brak) {
-      next(); *++e = PSH; expr(Assign);
-      if (tk == ']') next(); else { printf("%d: close bracket expected\n", line); exit(-1); }
-      if (t > PTR) { *++e = PSH; *++e = IMM; *++e = sizeof(int); *++e = MUL;  }
-      else if (t < PTR) { printf("%d: pointer type expected\n", line); exit(-1); }
-      *++e = ADD;
-      *++e = ((ty = t - PTR) == CHAR) ? LC : LI;
-    }
-    else { printf("%d: compiler error tk=%d\n", line, tk); exit(-1); }
-  }
-}
-
-void stmt()
-{
-  int *a, *b;
-
-  if (tk == If) {
-    next();
-    if (tk == '(') next(); else { printf("%d: open paren expected\n", line); exit(-1); }
-    expr(Assign);
-    if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
-    *++e = BZ; b = ++e;
-    stmt();
-    if (tk == Else) {
-      *b = (int)(e + 3); *++e = JMP; b = ++e;
-      next();
-      stmt();
-    }
-    *b = (int)(e + 1);
-  }
-  else if (tk == While) {
-    next();
-    a = e + 1;
-    if (tk == '(') next(); else { printf("%d: open paren expected\n", line); exit(-1); }
-    expr(Assign);
-    if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
-    *++e = BZ; b = ++e;
-    stmt();
-    *++e = JMP; *++e = (int)a;
-    *b = (int)(e + 1);
-  }
-  else if (tk == Return) {
-    next();
-    if (tk != ';') expr(Assign);
-    *++e = LEV;
-    if (tk == ';') next(); else { printf("%d: semicolon expected\n", line); exit(-1); }
-  }
-  else if (tk == '{') {
-    next();
-    while (tk != '}') stmt();
-    next();
-  }
-  else if (tk == ';') {
-    next();
-  }
-  else {
-    expr(Assign);
-    if (tk == ';') next(); else { printf("%d: semicolon expected\n", line); exit(-1); }
-  }
-}
-
-int main(int argc, char **argv)
-{
-  int fd, bt, ty, poolsz, *idmain;
-  int *pc, *sp, *bp, a, cycle; // vm registers
-  int i, *t; // temps
-
-  --argc; ++argv;
-  if (argc > 0 && **argv == '-' && (*argv)[1] == 's') { src = 1; --argc; ++argv; }
-  if (argc > 0 && **argv == '-' && (*argv)[1] == 'd') { debug = 1; --argc; ++argv; }
-  if (argc < 1) { printf("usage: c4 [-s] [-d] file ...\n"); return -1; }
-
-  if ((fd = open(*argv, 0)) < 0) { printf("could not open(%s)\n", *argv); return -1; }
-
-  poolsz = 256*1024; // arbitrary size
-  if (!(sym = malloc(poolsz))) { printf("could not malloc(%d) symbol area\n", poolsz); return -1; }
-  if (!(le = e = malloc(poolsz))) { printf("could not malloc(%d) text area\n", poolsz); return -1; }
-  if (!(data = malloc(poolsz))) { printf("could not malloc(%d) data area\n", poolsz); return -1; }
-  if (!(sp = malloc(poolsz))) { printf("could not malloc(%d) stack area\n", poolsz); return -1; }
-
-  memset(sym,  0, poolsz);
-  memset(e,    0, poolsz);
-  memset(data, 0, poolsz);
-
-  p = "char else enum if int return sizeof while "
-      "open read close printf malloc memset memcmp exit void main";
-  i = Char; while (i <= While) { next(); id[Tk] = i++; } // add keywords to symbol table
-  i = OPEN; while (i <= EXIT) { next(); id[Class] = Sys; id[Type] = INT; id[Val] = i++; } // add library to symbol table
-  next(); id[Tk] = Char; // handle void type
-  next(); idmain = id; // keep track of main
-
-  if (!(lp = p = malloc(poolsz))) { printf("could not malloc(%d) source area\n", poolsz); return -1; }
-  if ((i = read(fd, p, poolsz-1)) <= 0) { printf("read() returned %d\n", i); return -1; }
-  p[i] = 0;
-  close(fd);
-
-  // parse declarations
-  line = 1;
-  next();
-  while (tk) {
-    bt = INT; // basetype
-    if (tk == Int) next();
-    else if (tk == Char) { next(); bt = CHAR; }
-    else if (tk == Enum) {
-      next();
-      if (tk != '{') next();
-      if (tk == '{') {
-        next();
-        i = 0;
-        while (tk != '}') {
-          if (tk != Id) { printf("%d: bad enum identifier %d\n", line, tk); return -1; }
-          next();
-          if (tk == Assign) {
-            next();
-            if (tk != Num) { printf("%d: bad enum initializer\n", line); return -1; }
-            i = ival;
-            next();
-          }
-          id[Class] = Num; id[Type] = INT; id[Val] = i++;
-          if (tk == ',') next();
-        }
-        next();
-      }
-    }
-    while (tk != ';' && tk != '}') {
-      ty = bt;
-      while (tk == Mul) { next(); ty = ty + PTR; }
-      if (tk != Id) { printf("%d: bad global declaration\n", line); return -1; }
-      if (id[Class]) { printf("%d: duplicate global definition\n", line); return -1; }
-      next();
-      id[Type] = ty;
-      if (tk == '(') { // function
-        id[Class] = Fun;
-        id[Val] = (int)(e + 1);
-        next(); i = 0;
-        while (tk != ')') {
-          ty = INT;
-          if (tk == Int) next();
-          else if (tk == Char) { next(); ty = CHAR; }
-          while (tk == Mul) { next(); ty = ty + PTR; }
-          if (tk != Id) { printf("%d: bad parameter declaration\n", line); return -1; }
-          if (id[Class] == Loc) { printf("%d: duplicate parameter definition\n", line); return -1; }
-          id[HClass] = id[Class]; id[Class] = Loc;
-          id[HType]  = id[Type];  id[Type] = ty;
-          id[HVal]   = id[Val];   id[Val] = i++;
-          next();
-          if (tk == ',') next();
-        }
-        next();
-        if (tk != '{') { printf("%d: bad function definition\n", line); return -1; }
-        loc = ++i;
-        next();
-        while (tk == Int || tk == Char) {
-          bt = (tk == Int) ? INT : CHAR;
-          next();
-          while (tk != ';') {
-            ty = bt;
-            while (tk == Mul) { next(); ty = ty + PTR; }
-            if (tk != Id) { printf("%d: bad local declaration\n", line); return -1; }
-            if (id[Class] == Loc) { printf("%d: duplicate local definition\n", line); return -1; }
-            id[HClass] = id[Class]; id[Class] = Loc;
-            id[HType]  = id[Type];  id[Type] = ty;
-            id[HVal]   = id[Val];   id[Val] = ++i;
-            next();
-            if (tk == ',') next();
-          }
-          next();
-        }
-        *++e = ENT; *++e = i - loc;
-        while (tk != '}') stmt();
-        *++e = LEV;
-        id = sym; // unwind symbol table locals
-        while (id[Tk]) {
-          if (id[Class] == Loc) {
-            id[Class] = id[HClass];
-            id[Type] = id[HType];
-            id[Val] = id[HVal];
-          }
-          id = id + Idsz;
-        }
-      }
-      else {
-        id[Class] = Glo;
-        id[Val] = (int)data;
-        data = data + sizeof(int);
-      }
-      if (tk == ',') next();
-    }
-    next();
-  }
-
-  if (!(pc = (int *)idmain[Val])) { printf("main() not defined\n"); return -1; }
-  if (src) return 0;
-
-  // setup stack
-  sp = (int *)((int)sp + poolsz);
-  *--sp = EXIT; // call exit if main returns
-  *--sp = PSH; t = sp;
-  *--sp = argc;
-  *--sp = (int)argv;
-  *--sp = (int)t;
-
-  // run...
-  cycle = 0;
-  while (1) {
-    i = *pc++; ++cycle;
-    if (debug) {
-      printf("%d> %.4s", cycle,
-        &"LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,"
-         "OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,"
-         "OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,EXIT,"[i * 5]);
-      if (i <= ADJ) printf(" %d\n", *pc); else printf("\n");
-    }
-    if      (i == LEA) a = (int)(bp + *pc++);                             // load local address
-    else if (i == IMM) a = *pc++;                                         // load global address or immediate
-    else if (i == JMP) pc = (int *)*pc;                                   // jump
-    else if (i == JSR) { *--sp = (int)(pc + 1); pc = (int *)*pc; }        // jump to subroutine
-    else if (i == BZ)  pc = a ? pc + 1 : (int *)*pc;                      // branch if zero
-    else if (i == BNZ) pc = a ? (int *)*pc : pc + 1;                      // branch if not zero
-    else if (i == ENT) { *--sp = (int)bp; bp = sp; sp = sp - *pc++; }     // enter subroutine
-    else if (i == ADJ) sp = sp + *pc++;                                   // stack adjust
-    else if (i == LEV) { sp = bp; bp = (int *)*sp++; pc = (int *)*sp++; } // leave subroutine
-    else if (i == LI)  a = *(int *)a;                                     // load int
-    else if (i == LC)  a = *(char *)a;                                    // load char
-    else if (i == SI)  *(int *)*sp++ = a;                                 // store int
-    else if (i == SC)  a = *(char *)*sp++ = a;                            // store char
-    else if (i == PSH) *--sp = a;                                         // push
-
-    else if (i == OR)  a = *sp++ |  a;
-    else if (i == XOR) a = *sp++ ^  a;
-    else if (i == AND) a = *sp++ &  a;
-    else if (i == EQ)  a = *sp++ == a;
-    else if (i == NE)  a = *sp++ != a;
-    else if (i == LT)  a = *sp++ <  a;
-    else if (i == GT)  a = *sp++ >  a;
-    else if (i == LE)  a = *sp++ <= a;
-    else if (i == GE)  a = *sp++ >= a;
-    else if (i == SHL) a = *sp++ << a;
-    else if (i == SHR) a = *sp++ >> a;
-    else if (i == ADD) a = *sp++ +  a;
-    else if (i == SUB) a = *sp++ -  a;
-    else if (i == MUL) a = *sp++ *  a;
-    else if (i == DIV) a = *sp++ /  a;
-    else if (i == MOD) a = *sp++ %  a;
-
-    else if (i == OPEN) a = open((char *)sp[1], *sp);
-    else if (i == READ) a = read(sp[2], (char *)sp[1], *sp);
-    else if (i == CLOS) a = close(*sp);
-    else if (i == PRTF) { t = sp + pc[1]; a = printf((char *)t[-1], t[-2], t[-3], t[-4], t[-5], t[-6]); }
-    else if (i == MALC) a = (int)malloc(*sp);
-    else if (i == MSET) a = (int)memset((char *)sp[2], sp[1], *sp);
-    else if (i == MCMP) a = memcmp((char *)sp[2], (char *)sp[1], *sp);
-    else if (i == EXIT) { printf("exit(%d) cycle = %d\n", *sp, cycle); return *sp; }
-    else { printf("unknown instruction = %d! cycle = %d\n", i, cycle); return -1; }
-  }
-}
diff --git a/c5.c b/c5.c
new file mode 100644
index 0000000..e364689
--- /dev/null
+++ b/c5.c
@@ -0,0 +1,583 @@
+// c5.c - C in five functions
+
+// c4.c plus
+//   abstract syntax tree creation
+//   back-end code generator
+//   parameters passed in correct order
+//   various optimizations
+
+// Written by Robert Swierczek
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <memory.h>
+#include <fcntl.h>
+#ifdef _WIN32
+#include "w32.h"
+#endif
+
+#define int long
+
+char *p, *lp, // current position in source code
+     *data;   // data/bss pointer
+
+int *e, *le,  // current position in emitted code
+    *id,      // currently parsed identifier
+    *n,       // current node in abstract syntax tree
+    *sym,     // symbol table (simple list of identifiers)
+    tk,       // current token
+    ival,     // current token value
+    ty,       // current expression type
+    line,     // current line number
+    src,      // print source and assembly flag
+    debug;    // print executed instructions
+
+// tokens and classes (operators last and in precedence order)
+enum {
+  Num = 128, Fun, Sys, Glo, Loc, Id, Load, Enter,
+  Char, Else, Enum, If, Int, Return, Sizeof, While,
+  Assign, Cond, Lor, Lan, Or, Xor, And, Eq, Ne, Lt, Gt, Le, Ge, Shl, Shr, Add, Sub, Mul, Div, Mod, Inc, Dec, Brak
+};
+
+// opcodes
+enum { LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,
+       OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,
+       OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,MCPY,EXIT };
+
+// types
+enum { CHAR, INT, PTR };
+
+// identifier offsets (since we can't create an ident struct)
+enum { Tk, Hash, Name, Class, Type, Val, HClass, HType, HVal, Idsz };
+
+void next()
+{
+  char *pp;
+
+  while (tk = *p) {
+    ++p;
+    if (tk == '\n') {
+      if (src) {
+        printf("%ld: %.*s", line, p - lp, lp);
+        lp = p;
+        while (le < e) {
+          printf("%8.4s", &"LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,"
+                           "OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,"
+                           "OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,MCPY,EXIT,"[*++le * 5]);
+          if (*le <= ADJ) printf(" %ld\n", *++le); else printf("\n");
+        }
+      }
+      ++line;
+    }
+    else if (tk == '#') {
+      while (*p != 0 && *p != '\n') ++p;
+    }
+    else if ((tk >= 'a' && tk <= 'z') || (tk >= 'A' && tk <= 'Z') || tk == '_') {
+      pp = p - 1;
+      while ((*p >= 'a' && *p <= 'z') || (*p >= 'A' && *p <= 'Z') || (*p >= '0' && *p <= '9') || *p == '_')
+        tk = tk * 147 + *p++;
+      tk = (tk << 6) + (p - pp);
+      id = sym;
+      while (id[Tk]) {
+        if (tk == id[Hash] && !memcmp((char *)id[Name], pp, p - pp)) { tk = id[Tk]; return; }
+        id = id + Idsz;
+      }
+      id[Name] = (int)pp;
+      id[Hash] = tk;
+      tk = id[Tk] = Id;
+      return;
+    }
+    else if (tk >= '0' && tk <= '9') {
+      if (ival = tk - '0') { while (*p >= '0' && *p <= '9') ival = ival * 10 + *p++ - '0'; }
+      else if (*p == 'x' || *p == 'X') {
+        while ((tk = *++p) && ((tk >= '0' && tk <= '9') || (tk >= 'a' && tk <= 'f') || (tk >= 'A' && tk <= 'F')))
+          ival = ival * 16 + (tk & 15) + (tk >= 'A' ? 9 : 0);
+      }
+      else { while (*p >= '0' && *p <= '7') ival = ival * 8 + *p++ - '0'; }
+      tk = Num;
+      return;
+    }
+    else if (tk == '/') {
+      if (*p == '/') {
+        ++p;
+        while (*p != 0 && *p != '\n') ++p;
+      }
+      else {
+        tk = Div;
+        return;
+      }
+    }
+    else if (tk == '\'' || tk == '"') {
+      pp = data;
+      while (*p != 0 && *p != tk) {
+        if ((ival = *p++) == '\\') {
+          if ((ival = *p++) == 'n') ival = '\n';
+        }
+        if (tk == '"') *data++ = ival;
+      }
+      ++p;
+      if (tk == '"') ival = (int)pp; else tk = Num;
+      return;
+    }
+    else if (tk == '=') { if (*p == '=') { ++p; tk = Eq; } else tk = Assign; return; }
+    else if (tk == '+') { if (*p == '+') { ++p; tk = Inc; } else tk = Add; return; }
+    else if (tk == '-') { if (*p == '-') { ++p; tk = Dec; } else tk = Sub; return; }
+    else if (tk == '!') { if (*p == '=') { ++p; tk = Ne; } return; }
+    else if (tk == '<') { if (*p == '=') { ++p; tk = Le; } else if (*p == '<') { ++p; tk = Shl; } else tk = Lt; return; }
+    else if (tk == '>') { if (*p == '=') { ++p; tk = Ge; } else if (*p == '>') { ++p; tk = Shr; } else tk = Gt; return; }
+    else if (tk == '|') { if (*p == '|') { ++p; tk = Lor; } else tk = Or; return; }
+    else if (tk == '&') { if (*p == '&') { ++p; tk = Lan; } else tk = And; return; }
+    else if (tk == '^') { tk = Xor; return; }
+    else if (tk == '%') { tk = Mod; return; }
+    else if (tk == '*') { tk = Mul; return; }
+    else if (tk == '[') { tk = Brak; return; }
+    else if (tk == '?') { tk = Cond; return; }
+    else if (tk == '~' || tk == ';' || tk == '{' || tk == '}' || tk == '(' || tk == ')' || tk == ']' || tk == ',' || tk == ':') return;
+  }
+}
+
+void expr(int lev)
+{
+  int t, *d, *b;
+
+  if (!tk) { printf("%ld: unexpected eof in expression\n", line); exit(-1); }
+  else if (tk == Num) { *--n = ival; *--n = Num; next(); ty = INT; }
+  else if (tk == '"') {
+    *--n = ival; *--n = Num; next();
+    while (tk == '"') next();
+    data = (char *)((int)data + sizeof(int) & -sizeof(int)); ty = PTR;
+  }
+  else if (tk == Sizeof) {
+    next(); if (tk == '(') next(); else { printf("%ld: open paren expected in sizeof\n", line); exit(-1); }
+    ty = INT; if (tk == Int) next(); else if (tk == Char) { next(); ty = CHAR; }
+    while (tk == Mul) { next(); ty = ty + PTR; }
+    if (tk == ')') next(); else { printf("%ld: close paren expected in sizeof\n", line); exit(-1); }
+    *--n = (ty == CHAR) ? sizeof(char) : sizeof(int); *--n = Num;
+    ty = INT;
+  }
+  else if (tk == Id) {
+    d = id; next();
+    if (tk == '(') {
+      if (d[Class] != Sys && d[Class] != Fun) { printf("%ld: bad function call\n", line); exit(-1); }
+      next();
+      t = 0; b = 0;
+      while (tk != ')') { expr(Assign); *--n = (int)b; b = n; ++t; if (tk == ',') next(); }
+      next();
+      *--n = t; *--n = d[Val]; *--n = (int)b; *--n = d[Class];
+      ty = d[Type];
+    }
+    else if (d[Class] == Num) { *--n = d[Val]; *--n = Num; ty = INT; }
+    else {
+      if (d[Class] == Loc) { *--n = d[Val]; *--n = Loc; }
+      else if (d[Class] == Glo) { *--n = d[Val]; *--n = Num; }
+      else { printf("%ld: undefined variable\n", line); exit(-1); }
+      *--n = ty = d[Type]; *--n = Load;
+    }
+  }
+  else if (tk == '(') {
+    next();
+    if (tk == Int || tk == Char) {
+      t = (tk == Int) ? INT : CHAR; next();
+      while (tk == Mul) { next(); t = t + PTR; }
+      if (tk == ')') next(); else { printf("%ld: bad cast\n", line); exit(-1); }
+      expr(Inc);
+      ty = t;
+    }
+    else {
+      expr(Assign);
+      if (tk == ')') next(); else { printf("%ld: close paren expected\n", line); exit(-1); }
+    }
+  }
+  else if (tk == Mul) {
+    next(); expr(Inc);
+    if (ty > INT) ty = ty - PTR; else { printf("%ld: bad dereference\n", line); exit(-1); }
+    *--n = ty; *--n = Load;
+  }
+  else if (tk == And) {
+    next(); expr(Inc);
+    if (*n == Load) n = n+2; else { printf("%ld: bad address-of\n", line); exit(-1); }
+    ty = ty + PTR;
+  }
+  else if (tk == '!') {
+    next(); expr(Inc);
+    if (*n == Num) n[1] = !n[1]; else { *--n = 0; *--n = Num; --n; *n = (int)(n+3); *--n = Eq; }
+    ty = INT;
+  }
+  else if (tk == '~') {
+    next(); expr(Inc);
+    if (*n == Num) n[1] = ~n[1]; else { *--n = -1; *--n = Num; --n; *n = (int)(n+3); *--n = Xor; }
+    ty = INT;
+  }
+  else if (tk == Add) { next(); expr(Inc); ty = INT; }
+  else if (tk == Sub) {
+    next(); expr(Inc);
+    if (*n == Num) n[1] = -n[1]; else { *--n = -1; *--n = Num; --n; *n = (int)(n+3); *--n = Mul; }
+    ty = INT;
+  }
+  else if (tk == Inc || tk == Dec) {
+    t = tk; next(); expr(Inc);
+    if (*n == Load) *n = t; else { printf("%ld: bad lvalue in pre-increment\n", line); exit(-1); }
+  }
+  else { printf("%ld: bad expression\n", line); exit(-1); }
+
+  while (tk >= lev) { // "precedence climbing" or "Top Down Operator Precedence" method
+    t = ty; b = n;
+    if (tk == Assign) {
+      next();
+      if (*n != Load) { printf("%ld: bad lvalue in assignment\n", line); exit(-1); }
+      expr(Assign); *--n = (int)(b+2); *--n = ty = t; *--n = Assign;
+    }
+    else if (tk == Cond) {
+      next();
+      expr(Assign);
+      if (tk == ':') next(); else { printf("%ld: conditional missing colon\n", line); exit(-1); }
+      d = n;
+      expr(Cond);
+      --n; *n = (int)(n+1); *--n = (int)d; *--n = (int)b; *--n = Cond;
+    }
+    else if (tk == Lor) { next(); expr(Lan); if (*n==Num && *b==Num) n[1] = b[1] || n[1]; else { *--n = (int)b; *--n = Lor; } ty = INT; }
+    else if (tk == Lan) { next(); expr(Or);  if (*n==Num && *b==Num) n[1] = b[1] && n[1]; else { *--n = (int)b; *--n = Lan; } ty = INT; }
+    else if (tk == Or)  { next(); expr(Xor); if (*n==Num && *b==Num) n[1] = b[1] |  n[1]; else { *--n = (int)b; *--n = Or;  } ty = INT; }
+    else if (tk == Xor) { next(); expr(And); if (*n==Num && *b==Num) n[1] = b[1] ^  n[1]; else { *--n = (int)b; *--n = Xor; } ty = INT; }
+    else if (tk == And) { next(); expr(Eq);  if (*n==Num && *b==Num) n[1] = b[1] &  n[1]; else { *--n = (int)b; *--n = And; } ty = INT; }
+    else if (tk == Eq)  { next(); expr(Lt);  if (*n==Num && *b==Num) n[1] = b[1] == n[1]; else { *--n = (int)b; *--n = Eq;  } ty = INT; }
+    else if (tk == Ne)  { next(); expr(Lt);  if (*n==Num && *b==Num) n[1] = b[1] != n[1]; else { *--n = (int)b; *--n = Ne;  } ty = INT; }
+    else if (tk == Lt)  { next(); expr(Shl); if (*n==Num && *b==Num) n[1] = b[1] <  n[1]; else { *--n = (int)b; *--n = Lt;  } ty = INT; }
+    else if (tk == Gt)  { next(); expr(Shl); if (*n==Num && *b==Num) n[1] = b[1] >  n[1]; else { *--n = (int)b; *--n = Gt;  } ty = INT; }
+    else if (tk == Le)  { next(); expr(Shl); if (*n==Num && *b==Num) n[1] = b[1] <= n[1]; else { *--n = (int)b; *--n = Le;  } ty = INT; }
+    else if (tk == Ge)  { next(); expr(Shl); if (*n==Num && *b==Num) n[1] = b[1] >= n[1]; else { *--n = (int)b; *--n = Ge;  } ty = INT; }
+    else if (tk == Shl) { next(); expr(Add); if (*n==Num && *b==Num) n[1] = b[1] << n[1]; else { *--n = (int)b; *--n = Shl; } ty = INT; }
+    else if (tk == Shr) { next(); expr(Add); if (*n==Num && *b==Num) n[1] = b[1] >> n[1]; else { *--n = (int)b; *--n = Shr; } ty = INT; }
+    else if (tk == Add) {
+      next(); expr(Mul);
+      if ((ty = t) > PTR) { if (*n == Num) n[1] = n[1] * sizeof(int); else { *--n = sizeof(int); *--n = Num; --n; *n = (int)(n+3); *--n = Mul; } }
+      if (*n == Num && *b == Num) n[1] = b[1] + n[1]; else { *--n = (int)b; *--n = Add; }
+    }
+    else if (tk == Sub) {
+      next(); expr(Mul);
+      if ((ty = t) > PTR) { if (*n == Num) n[1] = n[1] * sizeof(int); else { *--n = sizeof(int); *--n = Num; --n; *n = (int)(n+3); *--n = Mul; } }
+      if (*n == Num && *b == Num) n[1] = b[1] - n[1]; else { *--n = (int)b; *--n = Sub; }
+    }
+    else if (tk == Mul) { next(); expr(Inc); if (*n==Num && *b==Num) n[1] = b[1] * n[1]; else { *--n = (int)b; *--n = Mul; } ty = INT; }
+    else if (tk == Div) { next(); expr(Inc); if (*n==Num && *b==Num) n[1] = b[1] / n[1]; else { *--n = (int)b; *--n = Div; } ty = INT; }
+    else if (tk == Mod) { next(); expr(Inc); if (*n==Num && *b==Num) n[1] = b[1] % n[1]; else { *--n = (int)b; *--n = Mod; } ty = INT; }
+    else if (tk == Inc || tk == Dec) {
+      if (*n == Load) *n = tk; else { printf("%ld: bad lvalue in post-increment\n", line); exit(-1); }
+      *--n = (ty > PTR) ? sizeof(int) : sizeof(char); *--n = Num;
+      *--n = (int)b; *--n = (tk == Inc) ? Sub : Add;
+      next();
+    }
+    else if (tk == Brak) {
+      next(); expr(Assign);
+      if (tk == ']') next(); else { printf("%ld: close bracket expected\n", line); exit(-1); }
+      if (t > PTR) { if (*n == Num) n[1] = n[1] * sizeof(int); else { *--n = sizeof(int); *--n = Num; --n; *n = (int)(n+3); *--n = Mul; } }
+      else if (t < PTR) { printf("%ld: pointer type expected\n", line); exit(-1); }
+      if (*n == Num && *b == Num) n[1] = b[1] + n[1]; else { *--n = (int)b; *--n = Add; }
+      *--n = ty = t - PTR; *--n = Load;
+    }
+    else { printf("%ld: compiler error tk=%ld\n", line, tk); exit(-1); }
+  }
+}
+
+void stmt()
+{
+  int *a, *b, *c;
+
+  if (tk == If) {
+    next();
+    if (tk == '(') next(); else { printf("%ld: open paren expected\n", line); exit(-1); }
+    expr(Assign); a = n;
+    if (tk == ')') next(); else { printf("%ld: close paren expected\n", line); exit(-1); }
+    stmt(); b = n;
+    if (tk == Else) { next(); stmt(); c = n; } else c = 0;
+    *--n = (int)c; *--n = (int)b; *--n = (int)a; *--n = Cond;
+  }
+  else if (tk == While) {
+    next();
+    if (tk == '(') next(); else { printf("%ld: open paren expected\n", line); exit(-1); }
+    expr(Assign); a = n;
+    if (tk == ')') next(); else { printf("%ld: close paren expected\n", line); exit(-1); }
+    stmt();
+    *--n = (int)a; *--n = While;
+  }
+  else if (tk == Return) {
+    next();
+    if (tk != ';') { expr(Assign); a = n; } else a = 0;
+    if (tk == ';') next(); else { printf("%ld: semicolon expected\n", line); exit(-1); }
+    *--n = (int)a; *--n = Return;
+  }
+  else if (tk == '{') {
+    next();
+    *--n = ';';
+    while (tk != '}') { a = n; stmt(); *--n = (int)a; *--n = '{'; }
+    next();
+  }
+  else if (tk == ';') {
+    next(); *--n = ';';
+  }
+  else {
+    expr(Assign);
+    if (tk == ';') next(); else { printf("%ld: semicolon expected\n", line); exit(-1); }
+  }
+}
+
+void gen(int *n)
+{
+  int i, *b;
+
+  i = *n;
+  if (i == Num) { *++e = IMM; *++e = n[1]; }
+  else if (i == Loc) { *++e = LEA; *++e = n[1]; }
+  else if (i == Load) { gen(n+2); *++e = (n[1] == CHAR) ? LC : LI; }
+  else if (i == Assign) { gen((int *)n[2]); *++e = PSH; gen(n+3); *++e = (n[1] == CHAR) ? SC : SI; }
+  else if (i == Inc || i == Dec) {
+    gen(n+2);
+    *++e = PSH; *++e = (n[1] == CHAR) ? LC : LI; *++e = PSH;
+    *++e = IMM; *++e = (n[1] > PTR) ? sizeof(int) : sizeof(char);
+    *++e = (i == Inc) ? ADD : SUB;
+    *++e = (n[1] == CHAR) ? SC : SI;
+  }  
+  else if (i == Cond) {
+    gen((int *)n[1]);
+    *++e = BZ; b = ++e;
+    gen((int *)n[2]);
+    if (n[3]) { *b = (int)(e + 3); *++e = JMP; b = ++e; gen((int *)n[3]); }
+    *b = (int)(e + 1);
+  }
+  else if (i == Lor) { gen((int *)n[1]); *++e = BNZ; b = ++e; gen(n+2); *b = (int)(e + 1); }
+  else if (i == Lan) { gen((int *)n[1]); *++e = BZ;  b = ++e; gen(n+2); *b = (int)(e + 1); }
+  else if (i == Or)  { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = OR; }
+  else if (i == Xor) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = XOR; }
+  else if (i == And) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = AND; }
+  else if (i == Eq)  { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = EQ; }
+  else if (i == Ne)  { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = NE; }
+  else if (i == Lt)  { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = LT; }
+  else if (i == Gt)  { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = GT; }
+  else if (i == Le)  { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = LE; }
+  else if (i == Ge)  { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = GE; }
+  else if (i == Shl) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = SHL; }
+  else if (i == Shr) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = SHR; }
+  else if (i == Add) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = ADD; }
+  else if (i == Sub) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = SUB; }
+  else if (i == Mul) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = MUL; }
+  else if (i == Div) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = DIV; }
+  else if (i == Mod) { gen((int *)n[1]); *++e = PSH; gen(n+2); *++e = MOD; }
+  else if (i == Sys || i == Fun) {
+    b = (int *)n[1];
+    while (b) { gen(b+1); *++e = PSH; b = (int *)*b; }
+    if (i == Fun) *++e = JSR; *++e = n[2];
+    if (n[3]) { *++e = ADJ; *++e = n[3]; }
+  }
+  else if (i == While) {
+    *++e = JMP; b = ++e; gen(n+2); *b = (int)(e + 1);
+    gen((int *)n[1]);
+    *++e = BNZ; *++e = (int)(b + 1);
+  }
+  else if (i == Return) { if (n[1]) gen((int *)n[1]); *++e = LEV; }
+  else if (i == '{') { gen((int *)n[1]); gen(n+2); }
+  else if (i == Enter) { *++e = ENT; *++e = n[1]; gen(n+2); *++e = LEV; }
+  else if (i != ';') { printf("%ld: compiler error gen=%ld\n", line, i); exit(-1); }
+}
+
+#undef int
+int main(int argc, char **argv)
+#define int long
+{
+  int fd, bt, ty, poolsz, *idmain, *ast;
+  int *pc, *sp, *bp, a, cycle; // vm registers
+  int i, *t; // temps
+
+  --argc; ++argv;
+  if (argc > 0 && **argv == '-' && (*argv)[1] == 's') { src = 1; --argc; ++argv; }
+  if (argc > 0 && **argv == '-' && (*argv)[1] == 'd') { debug = 1; --argc; ++argv; }
+  if (argc < 1) { printf("usage: c5 [-s] [-d] file ...\n"); return -1; }
+
+  if ((fd = open(*argv, 0)) < 0) { printf("could not open(%s)\n", *argv); return -1; }
+
+  poolsz = 256*1024; // arbitrary size
+  if (!(sym = malloc(poolsz))) { printf("could not malloc(%ld) symbol area\n", poolsz); return -1; }
+  if (!(le = e = malloc(poolsz))) { printf("could not malloc(%ld) text area\n", poolsz); return -1; }
+  if (!(data = malloc(poolsz))) { printf("could not malloc(%ld) data area\n", poolsz); return -1; }
+  if (!(sp = malloc(poolsz))) { printf("could not malloc(%ld) stack area\n", poolsz); return -1; }
+  if (!(ast = malloc(poolsz))) { printf("could not malloc(%ld) abstract syntax tree area\n", poolsz); return -1; }
+  ast = (int *)((int)ast + poolsz); // abstract syntax tree is most efficiently built as a stack
+
+  memset(sym,  0, poolsz);
+  memset(e,    0, poolsz);
+  memset(data, 0, poolsz);
+
+  p = "char else enum if int return sizeof while "
+      "open read close printf malloc memset memcmp memcpy exit void main";
+  i = Char; while (i <= While) { next(); id[Tk] = i++; } // add keywords to symbol table
+  i = OPEN; while (i <= EXIT) { next(); id[Class] = Sys; id[Type] = INT; id[Val] = i++; } // add library to symbol table
+  next(); id[Tk] = Char; // handle void type
+  next(); idmain = id; // keep track of main
+
+  if (!(lp = p = malloc(poolsz))) { printf("could not malloc(%ld) source area\n", poolsz); return -1; }
+  if ((i = read(fd, p, poolsz-1)) <= 0) { printf("read() returned %ld\n", i); return -1; }
+  p[i] = 0;
+  close(fd);
+
+  // parse declarations
+  line = 1;
+  next();
+  while (tk) {
+    bt = INT; // basetype
+    if (tk == Int) next();
+    else if (tk == Char) { next(); bt = CHAR; }
+    else if (tk == Enum) {
+      next();
+      if (tk != '{') next();
+      if (tk == '{') {
+        next();
+        i = 0;
+        while (tk != '}') {
+          if (tk != Id) { printf("%ld: bad enum identifier %ld\n", line, tk); return -1; }
+          next();
+          if (tk == Assign) {
+            next();
+            n = ast; expr(Cond);
+            if (*n != Num) { printf("%ld: bad enum initializer\n", line); return -1; }
+            i = n[1];
+          }
+          id[Class] = Num; id[Type] = INT; id[Val] = i++;
+          if (tk == ',') next();
+        }
+        next();
+      }
+    }
+    while (tk != ';' && tk != '}') {
+      ty = bt;
+      while (tk == Mul) { next(); ty = ty + PTR; }
+      if (tk != Id) { printf("%ld: bad global declaration\n", line); return -1; }
+      if (id[Class]) { printf("%ld: duplicate global definition\n", line); return -1; }
+      next();
+      id[Type] = ty;
+      if (tk == '(') { // function
+        id[Class] = Fun;
+        id[Val] = (int)(e + 1);
+        next(); i = 2;
+        while (tk != ')') {
+          ty = INT;
+          if (tk == Int) next();
+          else if (tk == Char) { next(); ty = CHAR; }
+          while (tk == Mul) { next(); ty = ty + PTR; }
+          if (tk != Id) { printf("%ld: bad parameter declaration\n", line); return -1; }
+          if (id[Class] == Loc) { printf("%ld: duplicate parameter definition\n", line); return -1; }
+          id[HClass] = id[Class]; id[Class] = Loc;
+          id[HType]  = id[Type];  id[Type] = ty;
+          id[HVal]   = id[Val];   id[Val] = i++;
+          next();
+          if (tk == ',') next();
+        }
+        next();
+        if (tk != '{') { printf("%ld: bad function definition\n", line); return -1; }
+        i = 0;
+        next();
+        while (tk == Int || tk == Char) {
+          bt = (tk == Int) ? INT : CHAR;
+          next();
+          while (tk != ';') {
+            ty = bt;
+            while (tk == Mul) { next(); ty = ty + PTR; }
+            if (tk != Id) { printf("%ld: bad local declaration\n", line); return -1; }
+            if (id[Class] == Loc) { printf("%ld: duplicate local definition\n", line); return -1; }
+            id[HClass] = id[Class]; id[Class] = Loc;
+            id[HType]  = id[Type];  id[Type] = ty;
+            id[HVal]   = id[Val];   id[Val] = --i;
+            next();
+            if (tk == ',') next();
+          }
+          next();
+        }
+        n = ast;
+        *--n = ';'; while (tk != '}') { t = n; stmt(); *--n = (int)t; *--n = '{'; }
+        *--n = -i; *--n = Enter;
+        gen(n);
+        id = sym; // unwind symbol table locals
+        while (id[Tk]) {
+          if (id[Class] == Loc) {
+            id[Class] = id[HClass];
+            id[Type] = id[HType];
+            id[Val] = id[HVal];
+          }
+          id = id + Idsz;
+        }
+      }
+      else {
+        id[Class] = Glo;
+        id[Val] = (int)data;
+        data = data + sizeof(int);
+      }
+      if (tk == ',') next();
+    }
+    next();
+  }
+
+  if (!(pc = (int *)idmain[Val])) { printf("main() not defined\n"); return -1; }
+  if (src) return 0;
+
+  // setup stack
+  sp = (int *)((int)sp + poolsz);
+  *--sp = EXIT; // call exit if main returns
+  *--sp = PSH; t = sp;
+  *--sp = (int)argv;
+  *--sp = argc;
+  *--sp = (int)t;
+
+  // run...
+  cycle = 0;
+  while (1) {
+    i = *pc++; ++cycle;
+    if (debug) {
+      printf("%ld> %.4s", cycle,
+        &"LEA ,IMM ,JMP ,JSR ,BZ  ,BNZ ,ENT ,ADJ ,LEV ,LI  ,LC  ,SI  ,SC  ,PSH ,"
+         "OR  ,XOR ,AND ,EQ  ,NE  ,LT  ,GT  ,LE  ,GE  ,SHL ,SHR ,ADD ,SUB ,MUL ,DIV ,MOD ,"
+         "OPEN,READ,CLOS,PRTF,MALC,MSET,MCMP,MCPY,EXIT,"[i * 5]);
+      if (i <= ADJ) printf(" %ld\n", *pc); else printf("\n");
+    }
+    if      (i == LEA) a = (int)(bp + *pc++);                             // load local address
+    else if (i == IMM) a = *pc++;                                         // load global address or immediate
+    else if (i == JMP) pc = (int *)*pc;                                   // jump
+    else if (i == JSR) { *--sp = (int)(pc + 1); pc = (int *)*pc; }        // jump to subroutine
+    else if (i == BZ)  pc = a ? pc + 1 : (int *)*pc;                      // branch if zero
+    else if (i == BNZ) pc = a ? (int *)*pc : pc + 1;                      // branch if not zero
+    else if (i == ENT) { *--sp = (int)bp; bp = sp; sp = sp - *pc++; }     // enter subroutine
+    else if (i == ADJ) sp = sp + *pc++;                                   // stack adjust
+    else if (i == LEV) { sp = bp; bp = (int *)*sp++; pc = (int *)*sp++; } // leave subroutine
+    else if (i == LI)  a = *(int *)a;                                     // load int
+    else if (i == LC)  a = *(char *)a;                                    // load char
+    else if (i == SI)  *(int *)*sp++ = a;                                 // store int
+    else if (i == SC)  a = *(char *)*sp++ = a;                            // store char
+    else if (i == PSH) *--sp = a;                                         // push
+
+    else if (i == OR)  a = *sp++ |  a;
+    else if (i == XOR) a = *sp++ ^  a;
+    else if (i == AND) a = *sp++ &  a;
+    else if (i == EQ)  a = *sp++ == a;
+    else if (i == NE)  a = *sp++ != a;
+    else if (i == LT)  a = *sp++ <  a;
+    else if (i == GT)  a = *sp++ >  a;
+    else if (i == LE)  a = *sp++ <= a;
+    else if (i == GE)  a = *sp++ >= a;
+    else if (i == SHL) a = *sp++ << a;
+    else if (i == SHR) a = *sp++ >> a;
+    else if (i == ADD) a = *sp++ +  a;
+    else if (i == SUB) a = *sp++ -  a;
+    else if (i == MUL) a = *sp++ *  a;
+    else if (i == DIV) a = *sp++ /  a;
+    else if (i == MOD) a = *sp++ %  a;
+
+    else if (i == OPEN) a = open((char *)*sp, sp[1]);
+    else if (i == READ) a = read(*sp, (char *)sp[1], sp[2]);
+    else if (i == CLOS) a = close(*sp);
+    else if (i == PRTF) a = printf((char *)*sp, sp[1], sp[2], sp[3], sp[4], sp[5]);
+    else if (i == MALC) a = (int)malloc(*sp);
+    else if (i == MSET) a = (int)memset((char *)*sp, sp[1], sp[2]);
+    else if (i == MCMP) a = memcmp((char *)*sp, (char *)sp[1], sp[2]);
+    else if (i == MCPY) a = (int)memcpy((char *)*sp, (char *)sp[1], sp[2]);
+    else if (i == EXIT) { printf("exit(%ld) cycle = %ld\n", *sp, cycle); return *sp; }
+    else { printf("unknown instruction = %ld! cycle = %ld\n", i, cycle); return -1; }
+  }
+}
diff --git a/c5x86.c b/c5x86.c
new file mode 100644
index 0000000..b298146
--- /dev/null
+++ b/c5x86.c
@@ -0,0 +1,579 @@
+// c5x86.c - C in five functions (native x86 version)
+
+// c4.c plus
+//   abstract syntax tree creation
+//   back-end code generator
+//   parameters passed in correct order
+//   various optimizations
+
+// Written by Robert Swierczek
+
+#include <unistd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <memory.h>
+#include <fcntl.h>
+#ifdef _WIN32
+#include "w32.h"
+#else
+#include <sys/mman.h>
+#endif
+
+char *p, *lp, // current position in source code
+     *e,      // current position in emitted code
+     *data,   // data/bss pointer
+     *dsym;   // external function lookup name
+
+int *id,      // currently parsed identifier
+    *n,       // current node in abstract syntax tree
+    *sym,     // symbol table (simple list of identifiers)
+    tk,       // current token
+    ival,     // current token value
+    ty,       // current expression type
+    line,     // current line number
+    src;      // print source and assembly flag
+
+// tokens and classes (operators last and in precedence order)
+enum {
+  Num = 128, Fun, Glo, Loc, Id, Load, Enter,
+  Char, Else, Enum, If, Int, Return, Sizeof, While,
+  Assign, Cond, Lor, Lan, Or, Xor, And, Eq, Ne, Lt, Gt, Le, Ge, Shl, Shr, Add, Sub, Mul, Div, Mod, Inc, Dec, Brak
+};
+
+// types
+enum { CHAR, INT, PTR };
+
+// identifier offsets (since we can't create an ident struct)
+enum { Tk, Hash, Name, Class, Type, Val, HClass, HType, HVal, Idsz };
+
+void next()
+{
+  char *pp;
+
+  while (tk = *p) {
+    ++p;
+    if (tk == '\n') {
+      if (src) {
+        printf("%d: %.*s", line, p - lp, lp);
+        lp = p;
+      }
+      ++line;
+    }
+    else if (tk == '#') {
+      while (*p != 0 && *p != '\n') ++p;
+    }
+    else if ((tk >= 'a' && tk <= 'z') || (tk >= 'A' && tk <= 'Z') || tk == '_') {
+      pp = p - 1;
+      while ((*p >= 'a' && *p <= 'z') || (*p >= 'A' && *p <= 'Z') || (*p >= '0' && *p <= '9') || *p == '_')
+        tk = tk * 147 + *p++;
+      tk = (tk << 6) + (p - pp);
+      id = sym;
+      while (id[Tk]) {
+        if (tk == id[Hash] && !memcmp((char *)id[Name], pp, p - pp)) { tk = id[Tk]; return; }
+        id = id + Idsz;
+      }
+      id[Name] = (int)pp;
+      id[Hash] = tk;
+      tk = id[Tk] = Id;
+      return;
+    }
+    else if (tk >= '0' && tk <= '9') {
+      if (ival = tk - '0') { while (*p >= '0' && *p <= '9') ival = ival * 10 + *p++ - '0'; }
+      else if (*p == 'x' || *p == 'X') {
+        while ((tk = *++p) && ((tk >= '0' && tk <= '9') || (tk >= 'a' && tk <= 'f') || (tk >= 'A' && tk <= 'F')))
+          ival = ival * 16 + (tk & 15) + (tk >= 'A' ? 9 : 0);
+      }
+      else { while (*p >= '0' && *p <= '7') ival = ival * 8 + *p++ - '0'; }
+      tk = Num;
+      return;
+    }
+    else if (tk == '/') {
+      if (*p == '/') {
+        ++p;
+        while (*p != 0 && *p != '\n') ++p;
+      }
+      else {
+        tk = Div;
+        return;
+      }
+    }
+    else if (tk == '\'' || tk == '"') {
+      pp = data;
+      while (*p != 0 && *p != tk) {
+        if ((ival = *p++) == '\\') {
+          if ((ival = *p++) == 'n') ival = '\n';
+        }
+        if (tk == '"') *data++ = ival;
+      }
+      ++p;
+      if (tk == '"') ival = (int)pp; else tk = Num;
+      return;
+    }
+    else if (tk == '=') { if (*p == '=') { ++p; tk = Eq; } else tk = Assign; return; }
+    else if (tk == '+') { if (*p == '+') { ++p; tk = Inc; } else tk = Add; return; }
+    else if (tk == '-') { if (*p == '-') { ++p; tk = Dec; } else tk = Sub; return; }
+    else if (tk == '!') { if (*p == '=') { ++p; tk = Ne; } return; }
+    else if (tk == '<') { if (*p == '=') { ++p; tk = Le; } else if (*p == '<') { ++p; tk = Shl; } else tk = Lt; return; }
+    else if (tk == '>') { if (*p == '=') { ++p; tk = Ge; } else if (*p == '>') { ++p; tk = Shr; } else tk = Gt; return; }
+    else if (tk == '|') { if (*p == '|') { ++p; tk = Lor; } else tk = Or; return; }
+    else if (tk == '&') { if (*p == '&') { ++p; tk = Lan; } else tk = And; return; }
+    else if (tk == '^') { tk = Xor; return; }
+    else if (tk == '%') { tk = Mod; return; }
+    else if (tk == '*') { tk = Mul; return; }
+    else if (tk == '[') { tk = Brak; return; }
+    else if (tk == '?') { tk = Cond; return; }
+    else if (tk == '~' || tk == ';' || tk == '{' || tk == '}' || tk == '(' || tk == ')' || tk == ']' || tk == ',' || tk == ':') return;
+  }
+}
+
+void expr(int lev)
+{
+  int t, *d, *b;
+
+  if (!tk) { printf("%d: unexpected eof in expression\n", line); exit(-1); }
+  else if (tk == Num) { *--n = ival; *--n = Num; next(); ty = INT; }
+  else if (tk == '"') {
+    *--n = ival; *--n = Num; next();
+    while (tk == '"') next();
+    data = (char *)((int)data + sizeof(int) & -sizeof(int)); ty = PTR;
+  }
+  else if (tk == Sizeof) {
+    next(); if (tk == '(') next(); else { printf("%d: open paren expected in sizeof\n", line); exit(-1); }
+    ty = INT; if (tk == Int) next(); else if (tk == Char) { next(); ty = CHAR; }
+    while (tk == Mul) { next(); ty = ty + PTR; }
+    if (tk == ')') next(); else { printf("%d: close paren expected in sizeof\n", line); exit(-1); }
+    *--n = (ty == CHAR) ? sizeof(char) : sizeof(int); *--n = Num;
+    ty = INT;
+  }
+  else if (tk == Id) {
+    d = id; next();
+    if (tk == '(') {
+      if (!d[Class]) {
+        memcpy(dsym, (char *)d[Name], d[Hash] & 63); dsym[d[Hash] & 63] = 0;
+        if (d[Val] = (int)dlsym(0, dsym)) d[Class] = Fun;
+      }
+      if (d[Class] != Fun) { printf("%d: bad function call\n", line); exit(-1); }
+      next();
+      t = 0; b = 0;
+      while (tk != ')') { expr(Assign); *--n = (int)b; b = n; ++t; if (tk == ',') next(); }
+      next();
+      *--n = t; *--n = d[Val]; *--n = (int)b; *--n = d[Class];
+      ty = d[Type];
+    }
+    else if (d[Class] == Num) { *--n = d[Val]; *--n = Num; ty = INT; }
+    else {
+      if (d[Class] == Loc) { *--n = d[Val]; *--n = Loc; }
+      else if (d[Class] == Glo) { *--n = d[Val]; *--n = Num; }
+      else { printf("%d: undefined variable\n", line); exit(-1); }
+      *--n = ty = d[Type]; *--n = Load;
+    }
+  }
+  else if (tk == '(') {
+    next();
+    if (tk == Int || tk == Char) {
+      t = (tk == Int) ? INT : CHAR; next();
+      while (tk == Mul) { next(); t = t + PTR; }
+      if (tk == ')') next(); else { printf("%d: bad cast\n", line); exit(-1); }
+      expr(Inc);
+      ty = t;
+    }
+    else {
+      expr(Assign);
+      if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
+    }
+  }
+  else if (tk == Mul) {
+    next(); expr(Inc);
+    if (ty > INT) ty = ty - PTR; else { printf("%d: bad dereference\n", line); exit(-1); }
+    *--n = ty; *--n = Load;
+  }
+  else if (tk == And) {
+    next(); expr(Inc);
+    if (*n == Load) n = n+2; else { printf("%d: bad address-of\n", line); exit(-1); }
+    ty = ty + PTR;
+  }
+  else if (tk == '!') {
+    next(); expr(Inc);
+    if (*n == Num) n[1] = !n[1]; else { *--n = 0; *--n = Num; --n; *n = (int)(n+3); *--n = Eq; }
+    ty = INT;
+  }
+  else if (tk == '~') {
+    next(); expr(Inc);
+    if (*n == Num) n[1] = ~n[1]; else { *--n = -1; *--n = Num; --n; *n = (int)(n+3); *--n = Xor; }
+    ty = INT;
+  }
+  else if (tk == Add) { next(); expr(Inc); ty = INT; }
+  else if (tk == Sub) {
+    next(); expr(Inc);
+    if (*n == Num) n[1] = -n[1]; else { *--n = -1; *--n = Num; --n; *n = (int)(n+3); *--n = Mul; }
+    ty = INT;
+  }
+  else if (tk == Inc || tk == Dec) {
+    t = tk; next(); expr(Inc);
+    if (*n == Load) *n = t; else { printf("%d: bad lvalue in pre-increment\n", line); exit(-1); }
+  }
+  else { printf("%d: bad expression\n", line); exit(-1); }
+
+  while (tk >= lev) { // "precedence climbing" or "Top Down Operator Precedence" method
+    t = ty; b = n;
+    if (tk == Assign) {
+      next();
+      if (*n != Load) { printf("%d: bad lvalue in assignment\n", line); exit(-1); }
+      expr(Assign); *--n = (int)(b+2); *--n = ty = t; *--n = Assign;
+    }
+    else if (tk == Cond) {
+      next();
+      expr(Assign);
+      if (tk == ':') next(); else { printf("%d: conditional missing colon\n", line); exit(-1); }
+      d = n;
+      expr(Cond);
+      --n; *n = (int)(n+1); *--n = (int)d; *--n = (int)b; *--n = Cond;
+    }
+    else if (tk == Lor) { next(); expr(Lan); if (*n==Num && *b==Num) n[1] = b[1] || n[1]; else { *--n = (int)b; *--n = Lor; } ty = INT; }
+    else if (tk == Lan) { next(); expr(Or);  if (*n==Num && *b==Num) n[1] = b[1] && n[1]; else { *--n = (int)b; *--n = Lan; } ty = INT; }
+    else if (tk == Or)  { next(); expr(Xor); if (*n==Num && *b==Num) n[1] = b[1] |  n[1]; else { *--n = (int)b; *--n = Or;  } ty = INT; }
+    else if (tk == Xor) { next(); expr(And); if (*n==Num && *b==Num) n[1] = b[1] ^  n[1]; else { *--n = (int)b; *--n = Xor; } ty = INT; }
+    else if (tk == And) { next(); expr(Eq);  if (*n==Num && *b==Num) n[1] = b[1] &  n[1]; else { *--n = (int)b; *--n = And; } ty = INT; }
+    else if (tk == Eq)  { next(); expr(Lt);  if (*n==Num && *b==Num) n[1] = b[1] == n[1]; else { *--n = (int)b; *--n = Eq;  } ty = INT; }
+    else if (tk == Ne)  { next(); expr(Lt);  if (*n==Num && *b==Num) n[1] = b[1] != n[1]; else { *--n = (int)b; *--n = Ne;  } ty = INT; }
+    else if (tk == Lt)  { next(); expr(Shl); if (*n==Num && *b==Num) n[1] = b[1] <  n[1]; else { *--n = (int)b; *--n = Lt;  } ty = INT; }
+    else if (tk == Gt)  { next(); expr(Shl); if (*n==Num && *b==Num) n[1] = b[1] >  n[1]; else { *--n = (int)b; *--n = Gt;  } ty = INT; }
+    else if (tk == Le)  { next(); expr(Shl); if (*n==Num && *b==Num) n[1] = b[1] <= n[1]; else { *--n = (int)b; *--n = Le;  } ty = INT; }
+    else if (tk == Ge)  { next(); expr(Shl); if (*n==Num && *b==Num) n[1] = b[1] >= n[1]; else { *--n = (int)b; *--n = Ge;  } ty = INT; }
+    else if (tk == Shl) { next(); expr(Add); if (*n==Num && *b==Num) n[1] = b[1] << n[1]; else { *--n = (int)b; *--n = Shl; } ty = INT; }
+    else if (tk == Shr) { next(); expr(Add); if (*n==Num && *b==Num) n[1] = b[1] >> n[1]; else { *--n = (int)b; *--n = Shr; } ty = INT; }
+    else if (tk == Add) {
+      next(); expr(Mul);
+      if ((ty = t) > PTR) { if (*n == Num) n[1] = n[1] * sizeof(int); else { *--n = sizeof(int); *--n = Num; --n; *n = (int)(n+3); *--n = Mul; } }
+      if (*n == Num && *b == Num) n[1] = b[1] + n[1]; else { *--n = (int)b; *--n = Add; }
+    }
+    else if (tk == Sub) {
+      next(); expr(Mul);
+      if ((ty = t) > PTR) { if (*n == Num) n[1] = n[1] * sizeof(int); else { *--n = sizeof(int); *--n = Num; --n; *n = (int)(n+3); *--n = Mul; } }
+      if (*n == Num && *b == Num) n[1] = b[1] - n[1]; else { *--n = (int)b; *--n = Sub; }
+    }
+    else if (tk == Mul) { next(); expr(Inc); if (*n==Num && *b==Num) n[1] = b[1] * n[1]; else { *--n = (int)b; *--n = Mul; } ty = INT; }
+    else if (tk == Div) { next(); expr(Inc); if (*n==Num && *b==Num) n[1] = b[1] / n[1]; else { *--n = (int)b; *--n = Div; } ty = INT; }
+    else if (tk == Mod) { next(); expr(Inc); if (*n==Num && *b==Num) n[1] = b[1] % n[1]; else { *--n = (int)b; *--n = Mod; } ty = INT; }
+    else if (tk == Inc || tk == Dec) {
+      if (*n == Load) *n = tk; else { printf("%d: bad lvalue in post-increment\n", line); exit(-1); }
+      *--n = (ty > PTR) ? sizeof(int) : sizeof(char); *--n = Num;
+      *--n = (int)b; *--n = (tk == Inc) ? Sub : Add;
+      next();
+    }
+    else if (tk == Brak) {
+      next(); expr(Assign);
+      if (tk == ']') next(); else { printf("%d: close bracket expected\n", line); exit(-1); }
+      if (t > PTR) { if (*n == Num) n[1] = n[1] * sizeof(int); else { *--n = sizeof(int); *--n = Num; --n; *n = (int)(n+3); *--n = Mul; } }
+      else if (t < PTR) { printf("%d: pointer type expected\n", line); exit(-1); }
+      if (*n == Num && *b == Num) n[1] = b[1] + n[1]; else { *--n = (int)b; *--n = Add; }
+      *--n = ty = t - PTR; *--n = Load;
+    }
+    else { printf("%d: compiler error tk=%d\n", line, tk); exit(-1); }
+  }
+}
+
+void stmt()
+{
+  int *a, *b, *c;
+
+  if (tk == If) {
+    next();
+    if (tk == '(') next(); else { printf("%d: open paren expected\n", line); exit(-1); }
+    expr(Assign); a = n;
+    if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
+    stmt(); b = n;
+    if (tk == Else) { next(); stmt(); c = n; } else c = 0;
+    *--n = (int)c; *--n = (int)b; *--n = (int)a; *--n = Cond;
+  }
+  else if (tk == While) {
+    next();
+    if (tk == '(') next(); else { printf("%d: open paren expected\n", line); exit(-1); }
+    expr(Assign); a = n;
+    if (tk == ')') next(); else { printf("%d: close paren expected\n", line); exit(-1); }
+    stmt();
+    *--n = (int)a; *--n = While;
+  }
+  else if (tk == Return) {
+    next();
+    if (tk != ';') { expr(Assign); a = n; } else a = 0;
+    if (tk == ';') next(); else { printf("%d: semicolon expected\n", line); exit(-1); }
+    *--n = (int)a; *--n = Return;
+  }
+  else if (tk == '{') {
+    next();
+    *--n = ';';
+    while (tk != '}') { a = n; stmt(); *--n = (int)a; *--n = '{'; }
+    next();
+  }
+  else if (tk == ';') {
+    next(); *--n = ';';
+  }
+  else {
+    expr(Assign);
+    if (tk == ';') next(); else { printf("%d: semicolon expected\n", line); exit(-1); }
+  }
+}
+
+void gen(int *n)
+{
+  int i; char *b;
+
+  i = *n;
+  if (i == Num) {
+    *e++ = 0xb8; *(int *)e = n[1]; e = e+4;             if (src) printf("    movl $%d, %%eax\n",n[1]);
+  }
+  else if (i == Loc) {
+    if (n[1] < -32 || n[1] > 32) { printf("%d: gen(lea) out of bounds\n", line); exit(-1); }
+    *(int *)e = 0x458d + (n[1] << 18); e = e+3;         if (src) printf("    leal $%d(%%ebp), %%eax\n", n[1]*4);
+  }
+  else if (i == Load) {
+    gen(n+2);
+    if (n[1] == CHAR) { *(int *)e = 0x00be0f; e = e+3;  if (src) printf("    movsbl (%%eax), %%eax\n"); }
+    else { *(int *)e = 0x008b; e = e+2;                 if (src) printf("    movl (%%eax), %%eax\n"); }
+  }
+  else if (i == Assign) {
+    gen((int *)n[2]); *e++ = 0x50;                      if (src) printf("    push %%eax\n");
+    gen(n+3); *e++ = 0x59;                              if (src) printf("    pop %%ecx\n");
+    if (n[1] == CHAR) { *(int *)e = 0x0188; e = e+2;    if (src) printf("    movb %%al, (%%ecx)\n"); }
+    else { *(int *)e = 0x0189; e = e+2;                 if (src) printf("    movl %%eax, (%%ecx)\n"); }
+  }
+  else if (i == Inc || i == Dec) {
+    gen(n+2); *e++ = 0x50;                              if (src) printf("    push %%eax\n");
+    if (n[1] == CHAR) { *(int *)e = 0x00be0f; e = e+3;  if (src) printf("    movsbl (%%eax), %%eax\n"); }
+    else { *(int *)e = 0x008b; e = e+2;                 if (src) printf("    movl (%%eax), %%eax\n"); }
+    i = ((i == Inc) ? 1 : -1) * ((n[1] > PTR) ? sizeof(int) : sizeof(char));
+    *e++ = 0xb9; *(int *)e = i; e = e+4;                if (src) printf("    movl $%d, %%ecx\n", i); 
+    *(int *)e = 0xc801; e = e+2;                        if (src) printf("    addl %%ecx, %%eax\n");
+    *e++ = 0x59;                                        if (src) printf("    pop %%ecx\n");
+    if (n[1] == CHAR) { *(int *)e = 0x0188; e = e+2;    if (src) printf("    movb %%al, (%%ecx)\n"); }
+    else { *(int *)e = 0x0189; e = e+2;                 if (src) printf("    movl %%eax, (%%ecx)\n"); }
+  }  
+  else if (i == Cond) {
+    gen((int *)n[1]);
+    *(int *)e = 0x840fc085; e = e+4; b = e; e = e+4;    if (src) printf("    test %%eax, %%eax\n    jeq <fwd>\n");
+    gen((int *)n[2]);
+    if (n[3]) {
+      *(int *)b = e+5 - b - 4;
+      *e++ = 0xe9; b = e; e = e + 4;                    if (src) printf("    jmp <fwd>\n");
+      gen((int *)n[3]);
+    }
+    *(int *)b = e - b - 4;
+  }
+  else if (i == Lor) {
+    gen((int *)n[1]);
+    *(int *)e = 0x850fc085; e = e+4; b = e; e = e+4;    if (src) printf("    test %%eax, %%eax\n    jne <fwd>\n");
+    gen(n+2);
+    *(int *)b = e - b - 4;
+  }
+  else if (i == Lan) {
+    gen((int *)n[1]);
+    *(int *)e = 0x840fc085; e = e+4; b = e; e = e+4;    if (src) printf("    test %%eax, %%eax\n    jeq <fwd>\n");
+    gen(n+2);
+    *(int *)b = e - b - 4;
+  }
+  else if (i >= Or && i <= Mod) {
+    gen(n+2); *e++ = 0x50;                              if (src) printf("    push %%eax\n");
+    gen((int *)n[1]); *e++ = 0x59;                      if (src) printf("    pop %%ecx\n");
+    if      (i == Or)  { *(int *)e = 0xc809; e = e+2;   if (src) printf("    orl %%ecx, %%eax\n"); }
+    else if (i == Xor) { *(int *)e = 0xc831; e = e+2;   if (src) printf("    xorl %%ecx, %%eax\n"); }
+    else if (i == And) { *(int *)e = 0xc821; e = e+2;   if (src) printf("    andl %%ecx, %%eax\n"); }
+    else if (i >= Eq && i <= Ge) {
+      *(int *)e = 0xc839; e = e+2;                      if (src) printf("    cmp %%eax, %%ecx\n");
+      *e++ = 0xb8; *(int *)e = 0; e = e+4;              if (src) printf("    mov $0, %%eax\n");    
+      if      (i == Eq) { *(int *)e = 0xc0940f;         if (src) printf("    sete %%al\n"); }
+      else if (i == Ne) { *(int *)e = 0xc0950f;         if (src) printf("    setne %%al\n"); }
+      else if (i == Lt) { *(int *)e = 0xc09c0f;         if (src) printf("    setl %%al\n"); }
+      else if (i == Gt) { *(int *)e = 0xc09f0f;         if (src) printf("    setg %%al\n"); }
+      else if (i == Le) { *(int *)e = 0xc09e0f;         if (src) printf("    setle %%al\n"); }
+      else              { *(int *)e = 0xc09d0f;         if (src) printf("    setge %%al\n"); }
+      e = e+3;
+    }
+    else if (i == Shl) { *(int *)e = 0xe0d3; e = e+2;   if (src) printf("    shl %%cl, %%eax\n"); }
+    else if (i == Shr) { *(int *)e = 0xf8d3; e = e+2;   if (src) printf("    sar %%cl, %%eax\n"); }
+    else if (i == Add) { *(int *)e = 0xc801; e = e+2;   if (src) printf("    addl %%ecx, %%eax\n"); }
+    else if (i == Sub) { *(int *)e = 0xc829; e = e+2;   if (src) printf("    subl %%ecx, %%eax\n"); }
+    else if (i == Mul) { *(int *)e = 0xc1af0f; e = e+3; if (src) printf("    imul %%ecx, %%eax\n"); }
+    else if (i == Div) { *(int *)e = 0xf9f799; e = e+3; if (src) printf("    cltd\n    idiv %%ecx, %%eax\n"); }
+    else if (i == Mod) { *(int *)e = 0x92f9f799; e=e+4; if (src) printf("    cltd\n    idiv %%ecx, %%eax\n    xchg %%edx, %%eax\n"); }
+  }
+  else if (i == Fun) {
+    i = n[1];
+    while (i) {
+      gen(((int *)i)+1); *e++ = 0x50; i = *(int *)i;    if (src) printf("    push %%eax\n");
+    }
+    *e++ = 0xe8; *(int *)e = n[2]-(int)e-4; e = e+4;    if (src) printf("    call <off32>\n");
+    if (n[3]) {
+      *(int *)e = 0xc481; e = e+2; 
+      *(int *)e = n[3]*4; e = e+4;                      if (src) printf("    add $%d, %%esp\n", n[3]*4);
+    }
+  }
+  else if (i == While) {
+    *e++ = 0xe9; b = e; e = e+4;                        if (src) printf("    jmp <fwd>\n");
+    gen(n+2);
+    *(int *)b = e - b - 4;
+    gen((int *)n[1]);
+    *(int *)e = 0x850fc085; e = e+4;                    if (src) printf("    test %%eax, %%eax\n");
+    *(int *)e = b - e; e = e+4;                         if (src) printf("    jne $%d\n", b - e);
+  }
+  else if (i == Return) {
+    if (n[1]) gen((int *)n[1]);                         if (src) printf("    mov %%ebp, %%esp\n");
+    *(int *)e = 0xc35dec89; e = e+4;                    if (src) printf("    pop %%ebp\n    ret\n");
+  }
+  else if (i == '{') {
+    gen((int *)n[1]); gen(n+2);
+  }
+  else if (i == Enter) {
+    *(int *)e = 0xe58955; e = e+3;                      if (src) printf("    push %%ebp;\n    mov %%esp, %%ebp\n");
+    if (n[1]) {
+      *(int *)e = 0xec81; e = e+2;
+      *(int *)e = n[1]*4; e = e+4;                      if (src) printf("    subl $%d, %%esp\n", n[1]*4);
+    }
+    gen(n+2);                                           if (src) printf("    mov %%ebp, %%esp\n");
+    *(int *)e = 0xc35dec89; e = e+4;                    if (src) printf("    pop %%ebp\n    ret\n");
+  }
+  else if (i != ';') { printf("%d: compiler error gen=%d\n", line, i); exit(-1); }
+}
+
+int main(int argc, char **argv)
+{
+  int fd, bt, ty, poolsz, *idmain, *ast;
+  int i, *t; // temps
+
+  --argc; ++argv;
+  if (argc > 0 && **argv == '-' && (*argv)[1] == 's') { src = 1; --argc; ++argv; }
+  if (argc < 1) { printf("usage: c5x86 [-s] file ...\n"); return -1; }
+
+  if ((fd = open(*argv, 0)) < 0) { printf("could not open(%s)\n", *argv); return -1; }
+
+  poolsz = 256*1024; // arbitrary size
+  if (!(sym = malloc(poolsz))) { printf("could not malloc(%d) symbol area\n", poolsz); return -1; }
+  if (!(data = malloc(poolsz))) { printf("could not malloc(%d) data area\n", poolsz); return -1; }
+  if (!(dsym = malloc(64))) { printf("could not malloc(64) dsym\n"); return -1; }
+  if (!(ast = malloc(poolsz))) { printf("could not malloc(%d) abstract syntax tree area\n", poolsz); return -1; }
+  ast = (int *)((int)ast + poolsz); // abstract syntax tree is most efficiently built as a stack
+
+  memset(sym,  0, poolsz);
+  memset(data, 0, poolsz);
+
+  if (!(e = mmap(0, poolsz, 7, 0x22, -1, 0))) { printf("could not mmap() executable memory\n"); return -1; }
+
+  p = "char else enum if int return sizeof while void main";
+  i = Char; while (i <= While) { next(); id[Tk] = i++; } // add keywords to symbol table
+  next(); id[Tk] = Char; // handle void type
+  next(); idmain = id; // keep track of main
+
+  if (!(lp = p = malloc(poolsz))) { printf("could not malloc(%d) source area\n", poolsz); return -1; }
+  if ((i = read(fd, p, poolsz-1)) <= 0) { printf("read() returned %d\n", i); return -1; }
+  p[i] = 0;
+  close(fd);
+
+  // parse declarations
+  line = 1;
+  next();
+  while (tk) {
+    bt = INT; // basetype
+    if (tk == Int) next();
+    else if (tk == Char) { next(); bt = CHAR; }
+    else if (tk == Enum) {
+      next();
+      if (tk != '{') next();
+      if (tk == '{') {
+        next();
+        i = 0;
+        while (tk != '}') {
+          if (tk != Id) { printf("%d: bad enum identifier %d\n", line, tk); return -1; }
+          next();
+          if (tk == Assign) {
+            next();
+            n = ast; expr(Cond);
+            if (*n != Num) { printf("%d: bad enum initializer\n", line); return -1; }
+            i = n[1];
+          }
+          id[Class] = Num; id[Type] = INT; id[Val] = i++;
+          if (tk == ',') next();
+        }
+        next();
+      }
+    }
+    while (tk != ';' && tk != '}') {
+      ty = bt;
+      while (tk == Mul) { next(); ty = ty + PTR; }
+      if (tk != Id) { printf("%d: bad global declaration\n", line); return -1; }
+      if (id[Class]) { printf("%d: duplicate global definition\n", line); return -1; }
+      next();
+      id[Type] = ty;
+      if (tk == '(') { // function
+        id[Class] = Fun;
+        id[Val] = (int)e;
+        next(); i = 2;
+        while (tk != ')') {
+          ty = INT;
+          if (tk == Int) next();
+          else if (tk == Char) { next(); ty = CHAR; }
+          while (tk == Mul) { next(); ty = ty + PTR; }
+          if (tk != Id) { printf("%d: bad parameter declaration\n", line); return -1; }
+          if (id[Class] == Loc) { printf("%d: duplicate parameter definition\n", line); return -1; }
+          id[HClass] = id[Class]; id[Class] = Loc;
+          id[HType]  = id[Type];  id[Type] = ty;
+          id[HVal]   = id[Val];   id[Val] = i++;
+          next();
+          if (tk == ',') next();
+        }
+        next();
+        if (tk != '{') { printf("%d: bad function definition\n", line); return -1; }
+        i = 0;
+        next();
+        while (tk == Int || tk == Char) {
+          bt = (tk == Int) ? INT : CHAR;
+          next();
+          while (tk != ';') {
+            ty = bt;
+            while (tk == Mul) { next(); ty = ty + PTR; }
+            if (tk != Id) { printf("%d: bad local declaration\n", line); return -1; }
+            if (id[Class] == Loc) { printf("%d: duplicate local definition\n", line); return -1; }
+            id[HClass] = id[Class]; id[Class] = Loc;
+            id[HType]  = id[Type];  id[Type] = ty;
+            id[HVal]   = id[Val];   id[Val] = --i;
+            next();
+            if (tk == ',') next();
+          }
+          next();
+        }
+        n = ast;
+        *--n = ';'; while (tk != '}') { t = n; stmt(); *--n = (int)t; *--n = '{'; }
+        *--n = -i; *--n = Enter;
+        gen(n);
+        id = sym; // unwind symbol table locals
+        while (id[Tk]) {
+          if (id[Class] == Loc) {
+            id[Class] = id[HClass];
+            id[Type] = id[HType];
+            id[Val] = id[HVal];
+          }
+          id = id + Idsz;
+        }
+      }
+      else {
+        id[Class] = Glo;
+        id[Val] = (int)data;
+        data = data + sizeof(int);
+      }
+      if (tk == ',') next();
+    }
+    next();
+  }
+
+  if (!idmain[Val]) { printf("main() not defined\n"); return -1; }
+  if (!src) {
+    t = (int *)e;
+    *e++ = 0xb8; *(char ***)e = argv; e = e+4; *e++ = 0x50;     // movl $argv, %eax; push %eax
+    *e++ = 0xb8; *(int *)   e = argc; e = e+4; *e++ = 0x50;     // movl $argc, %eax; push %eax
+    *e++ = 0xe8; *(int *)e = idmain[Val] - (int)e - 4; e = e+4; // call main
+    *e++ = 0x81; *e++ = 0xc4; *(int *)e = 8; e = e+4;           // add $8, %esp
+    *e++ = 0xc3;                                                // ret
+    qsort(dsym, 2, 1, (void *)t); // hack to call a function pointer
+    printf("exit(0) from c5x86\n");
+  }
+  return 0;
+}
diff --git a/w32.h b/w32.h
new file mode 100644
index 0000000..548a0ce
--- /dev/null
+++ b/w32.h
@@ -0,0 +1,32 @@
+#include <windows.h>
+void *mmap(void *addr, size_t len, int prot, int flags, int fildes, off_t off)
+{
+  HANDLE fm, h;
+  void *map;
+  const off_t maxSize = off + (off_t)len;
+
+  h = (HANDLE)_get_osfhandle(fildes);
+  fm = CreateFileMapping(h, NULL, PAGE_EXECUTE_READWRITE, 0, maxSize, NULL);
+  map = MapViewOfFile(fm, FILE_MAP_READ | FILE_MAP_WRITE | FILE_MAP_EXECUTE, 0, off, len);
+  CloseHandle(fm);
+  return map;
+}
+
+void *dlsym(void *handle, char *name)
+{
+  if (!strcmp(name, "open"  )) return &open;
+  if (!strcmp(name, "read"  )) return &read;
+  if (!strcmp(name, "close" )) return &close;
+  if (!strcmp(name, "printf")) return &printf;
+  if (!strcmp(name, "malloc")) return &malloc;
+  if (!strcmp(name, "memset")) return &memset;
+  if (!strcmp(name, "memcmp")) return &memcmp;
+  if (!strcmp(name, "memcpy")) return &memcpy;
+  if (!strcmp(name, "mmap"  )) return &mmap;
+  if (!strcmp(name, "dlsym" )) return &dlsym;
+  if (!strcmp(name, "qsort" )) return &qsort;
+  if (!strcmp(name, "exit"  )) return &exit;
+  return 0;
+}
+#define CHAR TYCHAR
+#define INT TYINT