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//    操作系统 win 8.1
//    编译环境 Visual Stuido 2017

#include<stdio.h>
#include<malloc.h>
#include<stdlib.h>

typedef int ElementType;        //    定义数据类型,可根据需要进行其他类型定义
                                //    链表节点的定义
typedef struct ListNode {
    ElementType  Element;        //    数据域，存放数据
    ListNode* Next;        //    指向下一个链表节点
}Node, *PNode;

//    链表创建函数定义
PNode CreateList(void) {
    int len ;    //    用于定义链表长度
    int val ;    //    用于存放节点数值
    PNode PHead = (PNode)malloc(sizeof(Node));    //    创建分配一个头节点内存空间
//头节点相当于链表的哨兵，不存放数据，指向首节点（第一个节点）
    if (PHead == NULL)    //    判断是否分配成功
    {
        printf("空间分配失败 \n");
        exit(-1);
    }

    PNode PTail = PHead;    //    链表的末尾节点，初始指向头节点
    PTail->Next = NULL;    //    最后一个节点指针置为空
    printf("请输入节点个数：");
    scanf_s("%d", &len);        //    输入节点个数
    for (int i = 0; i < len; i++) {

        PNode pNew = (PNode)malloc(sizeof(Node));    //    分配一个新节点
        if (pNew == NULL) {
            printf("分配新节点失败\n");
            exit(-1);
        }
        printf("请输入第 %d 个节点的数据：", i + 1);
        scanf_s("%d", &val);    //    输入链表节点的数据

        pNew->Element = val;    //    把数据赋值给节点数据域
        PTail->Next = pNew;    //    末尾节点指针指向下一个新节点
        pNew->Next = NULL;        //    新节点指针指向为空
        PTail = pNew;    //    将新节点复制给末尾节点        
    }
    printf("创建链表成功\n");
    return PHead;    //    返回头节点
}

//    主函数 
int main() {
    PNode List = CreateList();    //创建一个指针，使其指向新创建的链表的头指针    
    return 0;
}

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typedef struct st_type
{
int i;
int a[];
}type_a;

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/* main.c */
#include <stdio.h>

void swap(int* first, int* second)
{
    int temp = *first;
    *first = *second;
    *second = temp;
}

int main(void)
{
    int a = 10;
    int b = 20;

    printf("a = %d; b = %d;\n", a, b);
    swap(&a, &b);
    printf("a = %d; b = %d;\n", a, b);

    return 0;
}

1

gcc -S -o main.s main.c

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//wzh.c
#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
#include <unistd.h>
#include <fcntl.h>
#define int long long

char *p, *lp, *data; 

int *e,*le,*id,*sym,tk,ival,ty,loc,line,src,debug;   

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
};

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,FREE,MSET,MCMP,EXIT };

enum { CHAR, INT, PTR };

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,FREE,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) {
    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 free memset memcmp exit void main";
  i = Char; while (i <= While) { next(); id[Tk] = i++; }
  i = OPEN; while (i <= EXIT) { next(); id[Class] = Sys; id[Type] = INT; id[Val] = i++; }
  next(); id[Tk] = Char;
  next(); idmain = id;

  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);

  line = 1;
  next();
  while (tk) {
    bt = INT;
    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 == '(') {
        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;
        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;

  bp = sp = (int *)((int)sp + poolsz);
  *--sp = EXIT;
  *--sp = PSH; t = sp;
  *--sp = argc;
  *--sp = (int)argv;
  *--sp = (int)t;

  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,FREE,MSET,MCMP,EXIT,"[i * 5]);
      if (i <= ADJ) printf(" %d\n", *pc); else printf("\n");
    }
    if      (i == LEA) a = (int)(bp + *pc++);                            
    else if (i == IMM) a = *pc++;                                        
    else if (i == JMP) pc = (int *)*pc;                                 
    else if (i == JSR) { *--sp = (int)(pc + 1); pc = (int *)*pc; }       
    else if (i == BZ)  pc = a ? pc + 1 : (int *)*pc;                     
    else if (i == BNZ) pc = a ? (int *)*pc : pc + 1;                     
    else if (i == ENT) { *--sp = (int)bp; bp = sp; sp = sp - *pc++; }    
    else if (i == ADJ) sp = sp + *pc++;                                  
    else if (i == LEV) { sp = bp; bp = (int *)*sp++; pc = (int *)*sp++; }
    else if (i == LI)  a = *(int *)a;                                    
    else if (i == LC)  a = *(char *)a;                                   
    else if (i == SI)  *(int *)*sp++ = a;                                
    else if (i == SC)  a = *(char *)*sp++ = a;                           
    else if (i == PSH) *--sp = a;                                        

    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 == FREE) free((void *)*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; }
  }
}