#include "emu.h"
#include "rmov.h"

extern "C" void shld(void *);
extern "C" void shrd(void *);

void fsqrt()
{
  if (empty())
    return;
  if (st().tag == TW_Z)
    return;
  if (st().exp == EXP_MAX)
    return;
  if (st().sign == SIGN_NEG)
    return exception(EX_I);

  unsigned long long val = *(unsigned long long *)(&st().sigl);
  unsigned long long result = 0;
  unsigned long long side = 0;
  unsigned long long left = 0;
  int digit = 0;
  int i;
  if (st().exp & 1)
  {
    shrd(&val);
    st().exp++;
  }
  int exp = (st().exp - EXP_BIAS - 1)/2 - 64;
  while (!(((long *)&result)[1] & 0x80000000))
  {
    left = (left << 2) + (val >> 62);
    shld(&val);
    shld(&val);
    if (left >= side*2 + 1)
    {
      left -= side*2+1;
      side = (side+1)*2;
      shld(&result);
      result |= 1;
    }
    else
    {
      side *= 2;
      shld(&result);
    }
    exp++;
  }
  st().exp = exp + EXP_BIAS;
  st().sigl = result & 0xffffffff;
  st().sigh = result >> 32;
  st().tag = TW_V;
}

void frndint()
{
  if (empty())
    return;
  long long tmp;
  if (st().exp > EXP_BIAS+62)
    return;
  r_mov(st(), &tmp);
  r_mov(&tmp, st());
}

FUNC emu_17_table[] = {
  emu_bad, emu_bad, fsqrt, emu_bad, frndint, emu_bad, emu_bad, emu_bad
};

void emu_17()
{
  if (modrm > 0277)
  {
    (emu_17_table[modrm&7])();
  }
  else
  {
    // fstcw m16int
    *(short *)get_modrm() = control_word;
  }
}