vm.cpp

#include <cstdio>

#define S_SIZE 20
#define D_SIZE 100

enum OPCODE {END=0x66, ADD, SUB, MUL, DIV, INC, DEC, XOR, AND, PUSH, PUSHD, POP, MOV, MOVD, MOV2D, LOOP, CMP, JL, JG, JZ, INCD, DECD, FUN};

struct REG {
  unsigned int r0;
  unsigned int r1;
  unsigned int r2;
  unsigned int r3;
  unsigned int cf;   //Con flag
  unsigned char *db; //DD
  unsigned int *bp;  //BP
  unsigned int *sp;  //SP
  unsigned char *ip; //IP
};

class VM {
  private:
    struct REG r;
    virtual unsigned int vmp_getd();
    virtual unsigned int vmp_gets();
    virtual void vmp_setd(unsigned int x);
    virtual void vmc_nop();
    virtual void vmc_add();
    virtual void vmc_sub();
    virtual void vmc_mul();
    virtual void vmc_div();
    virtual void vmc_inc();
    virtual void vmc_dec();
    virtual void vmc_xor();
    virtual void vmc_and();
    virtual void vmc_push();
    virtual void vmc_pushd();
    virtual void vmc_pop();
    virtual void vmc_mov();
    virtual void vmc_movd();
    virtual void vmc_mov2d();
    virtual void vmc_loop();
    virtual void vmc_cmp();
    virtual void vmc_jl();
    virtual void vmc_jg();
    virtual void vmc_jz();
    virtual void vmc_incd();
    virtual void vmc_decd();
    virtual void vmc_fun();
  public:
    #ifdef DEBUG
      virtual void vm_debug();
    #endif
    virtual int vm_init(REG *init);
    virtual void vm_out(REG *out) const;
    virtual void vm_run();
};

#ifdef DEBUG
  void VM::vm_debug() {
    #ifdef DEBUG_INFO
      //__asm { int 3 }
      static int step = 0;
      printf("DEBUG:  (%d)\nR0 = %x\nR1 = %x\nR2 = %x\nR3 = %x\nCF = %x\nDB = %x\nBP = %x\nSP = %x\nIP = %x\n",\
	     step, r.r0, r.r1, r.r2, r.r3, r.cf, r.db, r.bp, r.sp, r.ip);
      step++;
    #endif
  }
#endif

unsigned int VM::vmp_getd() {
  unsigned char op = *(r.ip+1);
  op = op >> 4;
  switch (op) {
    case 0x00:
      return r.r0;
    case 0x01:
      return r.r1;
    case 0x02:
      return r.r2;
    case 0x03:
      return r.r3;
    case 0x04:
      return r.cf;
    default:
      return 0;
  }
}

unsigned int VM::vmp_gets() {
  unsigned char op = *(r.ip+1);
  op = op & 0x0f;
  switch (op) {
    case 0x00:
      return r.r0;
    case 0x01:
      return r.r1;
    case 0x02:
      return r.r2;
    case 0x03:
      return r.r3;
    case 0x04:
      return r.cf;
    default:
      return 0;
  }
}

void VM::vmp_setd(unsigned int x) {
  unsigned char op = *(r.ip+1);
  op = op >> 4;
  switch (op) {
    case 0x00:
      r.r0 = x;
      break;
    case 0x01:
      r.r1 = x;
      break;
    case 0x02:
      r.r2 = x;
      break;
    case 0x03:
      r.r3 = x;
      break;
    //case 0x04:
      //r.db = (unsigned char*)x;
  }
}

int VM::vm_init(REG *init) {
  #ifdef DEBUG
    printf("%s", "VM::vm_init\n");
  #endif
  r.r0 = init->r0;
  r.r1 = init->r1;
  r.r2 = init->r2;
  r.r3 = init->r3;
  r.cf = 0;
  r.db = init->db;
  r.bp = init->bp;
  r.sp = init->bp + (S_SIZE/2);
  r.ip = init->ip;
  return 0;
}

void VM::vm_out(REG *out) const {
  #ifdef DEBUG
    printf("%s", "VM::vm_out\n");
  #endif
  out->r0 = r.r0;
  out->r1 = r.r1;
  out->r2 = r.r2;
  out->r3 = r.r3;
  out->cf = r.cf;
  /*  out->db = r.db;
  out->bp = r.bp;
  out->sp = r.sp;
  out->ip = r.ip;*/
}

void VM::vmc_nop() {
  r.ip += 1;
  #ifdef DEBUG
    printf("%s", "NOP\n");
  #endif
}

void VM::vmc_add() {
  vmp_setd(vmp_getd() + vmp_gets());
  r.ip += 2;
  #ifdef DEBUG
    printf("ADD R%X, R%X\n", *(r.ip-1)>>4, *(r.ip-1)&0xF);
    vm_debug();
  #endif
}

void VM::vmc_sub() {
  vmp_setd(vmp_getd() - vmp_gets());
  r.ip += 2;
  #ifdef DEBUG
    printf("SUB R%X, R%X\n", *(r.ip-1)>>4, *(r.ip-1)&0xF);
    vm_debug();
  #endif
}

void VM::vmc_mul() {
  vmp_setd(vmp_getd() * vmp_gets());
  r.ip += 2;
  #ifdef DEBUG
    printf("MUL R%X, R%X\n", *(r.ip-1)>>4, *(r.ip-1)&0xF);
    vm_debug();
  #endif
}

void VM::vmc_div() {
  vmp_setd(vmp_getd() / vmp_gets());
  r.ip += 2;
  #ifdef DEBUG
    printf("DIV R%X, R%X\n", *(r.ip-1)>>4, *(r.ip-1)&0xF);
    vm_debug();
  #endif
}

void VM::vmc_inc() {
  vmp_setd(vmp_getd() + 1);
  r.ip += 2;
  #ifdef DEBUG
    printf("INC R%X\n", *(r.ip-1)>>4);
    vm_debug();
  #endif
}

void VM::vmc_dec() {
  vmp_setd(vmp_getd() - 1);
  r.ip += 2;
  #ifdef DEBUG
    printf("DEC R%X\n", *(r.ip-1)>>4);
    vm_debug();
  #endif
}

void VM::vmc_xor() {
  vmp_setd(vmp_getd() ^ vmp_gets());
  r.ip += 2;
  #ifdef DEBUG
    printf("XOR R%X, R%X\n", *(r.ip-1)>>4, *(r.ip-1)&0xF);
    vm_debug();
  #endif
}

void VM::vmc_and() {
  vmp_setd(vmp_getd() & vmp_gets());
  r.ip += 2;
  #ifdef DEBUG
    printf("AND R%X, R%X\n", *(r.ip-1)>>4, *(r.ip-1)&0xF);
    vm_debug();
  #endif
}

void VM::vmc_push() {
  unsigned int buf = vmp_getd();
  r.sp -= 1;
  *(r.sp) = buf;
  r.ip += 2;
  #ifdef DEBUG
    printf("PUSH R%X\n", *(r.ip-1)>>4);
    vm_debug();
  #endif
}

void VM::vmc_pushd() {
  unsigned int buf = 0;
  buf += (unsigned int)(*(r.ip + 1)) << 24;
  buf += (unsigned int)(*(r.ip + 2)) << 16;
  buf += (unsigned int)(*(r.ip + 3)) << 8;
  buf += (unsigned int)(*(r.ip + 4));
  r.sp -= 1;
  *(r.sp) = buf;
  r.ip += 5;
  #ifdef DEBUG
    printf("PUSHD $%x\n", buf);
    vm_debug();
  #endif
}

void VM::vmc_pop() {
  vmp_setd(*(r.sp));
  r.sp += 1;
  r.ip += 2;
  #ifdef DEBUG
    printf("POP R%X\n", *(r.ip-1)>>4);
    vm_debug();
  #endif
}

void VM::vmc_mov() {
  vmp_setd(vmp_gets());
  r.ip += 2;
  #ifdef DEBUG
    printf("MOV R%X, R%X\n", *(r.ip-1)>>4, *(r.ip-1)&0xF);
    vm_debug();
  #endif
}

void VM::vmc_movd() {
  char buf;
  buf = *(r.db);
  vmp_setd((unsigned int)buf);
  r.ip += 2;
  #ifdef DEBUG
    printf("MOVD R%X\n", *(r.ip-1)>>4);
    vm_debug();
  #endif
}

void VM::vmc_mov2d() {
  unsigned char buf = (unsigned char)vmp_getd();
  *(r.db) = buf;
  r.ip += 2;
  #ifdef DEBUG
    printf("MOV2D R%X\n", *(r.ip-1)>>4);
    vm_debug();
  #endif
}

void VM::vmc_loop() {
  unsigned int i;
  if (r.r3 != 0) {
    r.r3--;
    i = (unsigned int)(*(r.ip+1));
    r.ip -= i; 
  }
  else { 
    r.ip += 2;
  }
  #ifdef DEBUG
    printf("LOOP -%X\n", i);
    vm_debug();
  #endif
}

void VM::vmc_cmp() {
  if (vmp_getd() == vmp_gets())
    r.cf = 0;
  if (vmp_getd() < vmp_gets())
    r.cf = -1;
  if (vmp_getd() > vmp_gets())
    r.cf = 1;
  r.ip += 2;
  #ifdef DEBUG
    if (r.cf == 0)
      printf("CMP =\n");
    if (r.cf == -1)
      printf("CMP <\n");
    if (r.cf == 1)
      printf("CMP >\n");
    vm_debug();
  #endif
}

void VM::vmc_jl() {
  unsigned int i;
  if (r.cf == -1) {
    i = (unsigned int)(*(r.ip+1)) + 2;
    r.ip += i;
  } else {
    r.ip += 2;
  }
  #ifdef DEBUG
    if (r.cf == -1)
      printf("JL +%X (JUMPED)\n", i);
    else
      printf("JL (NOT JUMPED)\n");
    vm_debug();
  #endif 
}

void VM::vmc_jg() {
  unsigned int i;
  if (r.cf == 1) {
    i = (unsigned int)(*(r.ip+1)) + 2;
    r.ip += i;
  } else {
    r.ip += 2;
  }
  #ifdef DEBUG
    if (r.cf == 1)
      printf("JG +%X (JUMPED)\n", i);
    else
      printf("JG (NOT JUMPED)\n");
    vm_debug();
  #endif
}

void VM::vmc_jz() {
  unsigned int i;
  if (r.cf == 0) {
    i = (unsigned int)(*(r.ip+1)) + 2;
    r.ip += i;
  }
  else {
    r.ip += 2;
  }
  #ifdef DEBUG
    if (r.cf == 0)
      printf("JZ +%X (JUMPED)\n", i);
    else
      printf("JZ (NOT JUMPED)\n");
    vm_debug();
  #endif  
}

void VM::vmc_incd() {
  r.db++;
  r.ip++;
  #ifdef DEBUG
    printf("INCD\n");
    vm_debug();
  #endif
}

void VM::vmc_decd() {
  r.db--;
  r.ip++;
  #ifdef DEBUG
    printf("DECD\n");
    vm_debug();
  #endif
}

void VM::vmc_fun() {
  int i;
  for (i=1; i<FUN_SIZE; ++i) {
    *(r.ip+i) ^= FUN_KEY;
  }
  r.ip += FUN_SIZE;
  #ifdef DEBUG
    printf("FUN\n");
    vm_debug();
  #endif
}

void VM::vm_run() {
  #ifdef DEBUG
    printf("%s", "VM::vm_run\n");
    vm_debug();
  #endif
  while(1) {
    unsigned char *addr = r.ip;
    #ifdef DEBUG
      printf("OPCODE: %02X\t", *addr);
    #endif 
    switch (*addr) {
      case END: 
        goto end;
      case ADD:
        vmc_add();
        break;
      case SUB:
        vmc_sub();
        break;
      case MUL:
        vmc_mul();
        break;
      case DIV:
        vmc_div();
        break;
      case INC:
        vmc_inc();
        break;
      case DEC:
        vmc_dec();
        break;
      case XOR:
        vmc_xor();
        break;
      case AND:
        vmc_and();
        break;
      case PUSH:
        vmc_push();
        break;
      case PUSHD:
        vmc_pushd();
        break;
      case POP:
        vmc_pop();
        break;
      case MOV:
        vmc_mov();
        break;
      case MOVD:
        vmc_movd();
        break;
      case MOV2D:
        vmc_mov2d();
        break;
      case LOOP:
        vmc_loop();
        break;
      case CMP:
	vmc_cmp();
        break;
      case JL:
        vmc_jl();
        break;
      case JG:
        vmc_jg();
        break;
      case JZ:
        vmc_jz();
        break;
      case INCD:
        vmc_incd();
        break;
      case DECD:
        vmc_decd();
        break;
      case FUN:
        vmc_fun();
        break;
      default:
        vmc_nop();
    }
  }
  #ifdef DEBUG
    printf("%s", "VM::END\n");
  #endif 
 end:
    return;
}