auto LR35902::op_xx() {
}

auto LR35902::op_cb() {
  instructionCB();
}

//8-bit load commands

auto LR35902::op_ld_r_r(uint x, uint y) {
  r[x] = r[y];
}

auto LR35902::op_ld_r_n(uint x) {
  r[x] = read(r[PC]++);
}

auto LR35902::op_ld_r_hl(uint x) {
  r[x] = read(r[HL]);
}

auto LR35902::op_ld_hl_r(uint x) {
  write(r[HL], r[x]);
}

auto LR35902::op_ld_hl_n() {
  write(r[HL], read(r[PC]++));
}

auto LR35902::op_ld_a_rr(uint x) {
  r[A] = read(r[x]);
}

auto LR35902::op_ld_a_nn() {
  uint8 lo = read(r[PC]++);
  uint8 hi = read(r[PC]++);
  r[A] = read((hi << 8) | (lo << 0));
}

auto LR35902::op_ld_rr_a(uint x) {
  write(r[x], r[A]);
}

auto LR35902::op_ld_nn_a() {
  uint8 lo = read(r[PC]++);
  uint8 hi = read(r[PC]++);
  write((hi << 8) | (lo << 0), r[A]);
}

auto LR35902::op_ld_a_ffn() {
  r[A] = read(0xff00 + read(r[PC]++));
}

auto LR35902::op_ld_ffn_a() {
  write(0xff00 + read(r[PC]++), r[A]);
}

auto LR35902::op_ld_a_ffc() {
  r[A] = read(0xff00 + r[C]);
}

auto LR35902::op_ld_ffc_a() {
  write(0xff00 + r[C], r[A]);
}

auto LR35902::op_ldi_hl_a() {
  write(r[HL], r[A]);
  r[HL]++;
}

auto LR35902::op_ldi_a_hl() {
  r[A] = read(r[HL]);
  r[HL]++;
}

auto LR35902::op_ldd_hl_a() {
  write(r[HL], r[A]);
  r[HL]--;
}

auto LR35902::op_ldd_a_hl() {
  r[A] = read(r[HL]);
  r[HL]--;
}

//16-bit load commands

auto LR35902::op_ld_rr_nn(uint x) {
  r[x]  = read(r[PC]++) << 0;
  r[x] |= read(r[PC]++) << 8;
}

auto LR35902::op_ld_nn_sp() {
  uint16 addr = read(r[PC]++) << 0;
  addr |= read(r[PC]++) << 8;
  write(addr + 0, r[SP] >> 0);
  write(addr + 1, r[SP] >> 8);
}

auto LR35902::op_ld_sp_hl() {
  r[SP] = r[HL];
  io();
}

auto LR35902::op_push_rr(uint x) {
  io();
  write(--r[SP], r[x] >> 8);
  write(--r[SP], r[x] >> 0);
}

auto LR35902::op_pop_rr(uint x) {
  r[x]  = read(r[SP]++) << 0;
  r[x] |= read(r[SP]++) << 8;
}

//8-bit arithmetic commands

auto LR35902::opi_add_a(uint8 x) {
  uint16 rh = r[A] + x;
  uint16 rl = (r[A] & 0x0f) + (x & 0x0f);
  r[A] = rh;
  r.f.z = (uint8)rh == 0;
  r.f.n = 0;
  r.f.h = rl > 0x0f;
  r.f.c = rh > 0xff;
}

auto LR35902::op_add_a_r(uint x) { opi_add_a(r[x]); }
auto LR35902::op_add_a_n() { opi_add_a(read(r[PC]++)); }
auto LR35902::op_add_a_hl() { opi_add_a(read(r[HL])); }

auto LR35902::opi_adc_a(uint8 x) {
  uint16 rh = r[A] + x + r.f.c;
  uint16 rl = (r[A] & 0x0f) + (x & 0x0f) + r.f.c;
  r[A] = rh;
  r.f.z = (uint8)rh == 0;
  r.f.n = 0;
  r.f.h = rl > 0x0f;
  r.f.c = rh > 0xff;
}

auto LR35902::op_adc_a_r(uint x) { opi_adc_a(r[x]); }
auto LR35902::op_adc_a_n() { opi_adc_a(read(r[PC]++)); }
auto LR35902::op_adc_a_hl() { opi_adc_a(read(r[HL])); }

auto LR35902::opi_sub_a(uint8 x) {
  uint16 rh = r[A] - x;
  uint16 rl = (r[A] & 0x0f) - (x & 0x0f);
  r[A] = rh;
  r.f.z = (uint8)rh == 0;
  r.f.n = 1;
  r.f.h = rl > 0x0f;
  r.f.c = rh > 0xff;
}

auto LR35902::op_sub_a_r(uint x) { opi_sub_a(r[x]); }
auto LR35902::op_sub_a_n() { opi_sub_a(read(r[PC]++)); }
auto LR35902::op_sub_a_hl() { opi_sub_a(read(r[HL])); }

auto LR35902::opi_sbc_a(uint8 x) {
  uint16 rh = r[A] - x - r.f.c;
  uint16 rl = (r[A] & 0x0f) - (x & 0x0f) - r.f.c;
  r[A] = rh;
  r.f.z = (uint8)rh == 0;
  r.f.n = 1;
  r.f.h = rl > 0x0f;
  r.f.c = rh > 0xff;
}

auto LR35902::op_sbc_a_r(uint x) { opi_sbc_a(r[x]); }
auto LR35902::op_sbc_a_n() { opi_sbc_a(read(r[PC]++)); }
auto LR35902::op_sbc_a_hl() { opi_sbc_a(read(r[HL])); }

auto LR35902::opi_and_a(uint8 x) {
  r[A] &= x;
  r.f.z = r[A] == 0;
  r.f.n = 0;
  r.f.h = 1;
  r.f.c = 0;
}

auto LR35902::op_and_a_r(uint x) { opi_and_a(r[x]); }
auto LR35902::op_and_a_n() { opi_and_a(read(r[PC]++)); }
auto LR35902::op_and_a_hl() { opi_and_a(read(r[HL])); }

auto LR35902::opi_xor_a(uint8 x) {
  r[A] ^= x;
  r.f.z = r[A] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = 0;
}

auto LR35902::op_xor_a_r(uint x) { opi_xor_a(r[x]); }
auto LR35902::op_xor_a_n() { opi_xor_a(read(r[PC]++)); }
auto LR35902::op_xor_a_hl() { opi_xor_a(read(r[HL])); }

auto LR35902::opi_or_a(uint8 x) {
  r[A] |= x;
  r.f.z = r[A] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = 0;
}

auto LR35902::op_or_a_r(uint x) { opi_or_a(r[x]); }
auto LR35902::op_or_a_n() { opi_or_a(read(r[PC]++)); }
auto LR35902::op_or_a_hl() { opi_or_a(read(r[HL])); }

auto LR35902::opi_cp_a(uint8 x) {
  uint16 rh = r[A] - x;
  uint16 rl = (r[A] & 0x0f) - (x & 0x0f);
  r.f.z = (uint8)rh == 0;
  r.f.n = 1;
  r.f.h = rl > 0x0f;
  r.f.c = rh > 0xff;
}

auto LR35902::op_cp_a_r(uint x) { opi_cp_a(r[x]); }
auto LR35902::op_cp_a_n() { opi_cp_a(read(r[PC]++)); }
auto LR35902::op_cp_a_hl() { opi_cp_a(read(r[HL])); }

auto LR35902::op_inc_r(uint x) {
  r[x]++;
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = (r[x] & 0x0f) == 0x00;
}

auto LR35902::op_inc_hl() {
  uint8 n = read(r[HL]);
  write(r[HL], ++n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = (n & 0x0f) == 0x00;
}

auto LR35902::op_dec_r(uint x) {
  r[x]--;
  r.f.z = r[x] == 0;
  r.f.n = 1;
  r.f.h = (r[x] & 0x0f) == 0x0f;
}

auto LR35902::op_dec_hl() {
  uint8 n = read(r[HL]);
  write(r[HL], --n);
  r.f.z = n == 0;
  r.f.n = 1;
  r.f.h = (n & 0x0f) == 0x0f;
}

auto LR35902::op_daa() {
  uint16 a = r[A];
  if(r.f.n == 0) {
    if(r.f.h || (a & 0x0f) > 0x09) a += 0x06;
    if(r.f.c || (a       ) > 0x9f) a += 0x60;
  } else {
    if(r.f.h) {
      a -= 0x06;
      if(r.f.c == 0) a &= 0xff;
    }
    if(r.f.c) a -= 0x60;
  }
  r[A] = a;
  r.f.z = r[A] == 0;
  r.f.h = 0;
  r.f.c |= a & 0x100;
}

auto LR35902::op_cpl() {
  r[A] ^= 0xff;
  r.f.n = 1;
  r.f.h = 1;
}

//16-bit arithmetic commands

auto LR35902::op_add_hl_rr(uint x) {
  io();
  uint32 rb = (r[HL] + r[x]);
  uint32 rn = (r[HL] & 0xfff) + (r[x] & 0xfff);
  r[HL] = rb;
  r.f.n = 0;
  r.f.h = rn > 0x0fff;
  r.f.c = rb > 0xffff;
}

auto LR35902::op_inc_rr(uint x) {
  io();
  r[x]++;
}

auto LR35902::op_dec_rr(uint x) {
  io();
  r[x]--;
}

auto LR35902::op_add_sp_n() {
  int n = (int8)read(r[PC]++);
  r.f.z = 0;
  r.f.n = 0;
  r.f.h = ((r[SP] & 0x0f) + (n & 0x0f)) > 0x0f;
  r.f.c = ((r[SP] & 0xff) + (n & 0xff)) > 0xff;
  r[SP] += n;
  io();
  io();
}

auto LR35902::op_ld_hl_sp_n() {
  int n = (int8)read(r[PC]++);
  r.f.z = 0;
  r.f.n = 0;
  r.f.h = ((r[SP] & 0x0f) + (n & 0x0f)) > 0x0f;
  r.f.c = ((r[SP] & 0xff) + (n & 0xff)) > 0xff;
  r[HL] = r[SP] + n;
  io();
}

//rotate/shift commands

auto LR35902::op_rlca() {
  r[A] = (r[A] << 1) | (r[A] >> 7);
  r.f.z = 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = r[A] & 0x01;
}

auto LR35902::op_rla() {
  bool c = r[A] & 0x80;
  r[A] = (r[A] << 1) | (r.f.c << 0);
  r.f.z = 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_rrca() {
  r[A] = (r[A] >> 1) | (r[A] << 7);
  r.f.z = 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = r[A] & 0x80;
}

auto LR35902::op_rra() {
  bool c = r[A] & 0x01;
  r[A] = (r[A] >> 1) | (r.f.c << 7);
  r.f.z = 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_rlc_r(uint x) {
  r[x] = (r[x] << 1) | (r[x] >> 7);
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = r[x] & 0x01;
}

auto LR35902::op_rlc_hl() {
  uint8 n = read(r[HL]);
  n = (n << 1) | (n >> 7);
  write(r[HL], n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = n & 0x01;
}

auto LR35902::op_rl_r(uint x) {
  bool c = r[x] & 0x80;
  r[x] = (r[x] << 1) | (r.f.c << 0);
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_rl_hl() {
  uint8 n = read(r[HL]);
  bool c = n & 0x80;
  n = (n << 1) | (r.f.c << 0);
  write(r[HL], n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_rrc_r(uint x) {
  r[x] = (r[x] >> 1) | (r[x] << 7);
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = r[x] & 0x80;
}

auto LR35902::op_rrc_hl() {
  uint8 n = read(r[HL]);
  n = (n >> 1) | (n << 7);
  write(r[HL], n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = n & 0x80;
}

auto LR35902::op_rr_r(uint x) {
  bool c = r[x] & 0x01;
  r[x] = (r[x] >> 1) | (r.f.c << 7);
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_rr_hl() {
  uint8 n = read(r[HL]);
  bool c = n & 0x01;
  n = (n >> 1) | (r.f.c << 7);
  write(r[HL], n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_sla_r(uint x) {
  bool c = r[x] & 0x80;
  r[x] <<= 1;
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_sla_hl() {
  uint8 n = read(r[HL]);
  bool c = n & 0x80;
  n <<= 1;
  write(r[HL], n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_swap_r(uint x) {
  r[x] = (r[x] << 4) | (r[x] >> 4);
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = 0;
}

auto LR35902::op_swap_hl() {
  uint8 n = read(r[HL]);
  n = (n << 4) | (n >> 4);
  write(r[HL], n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = 0;
}

auto LR35902::op_sra_r(uint x) {
  bool c = r[x] & 0x01;
  r[x] = (int8)r[x] >> 1;
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_sra_hl() {
  uint8 n = read(r[HL]);
  bool c = n & 0x01;
  n = (int8)n >> 1;
  write(r[HL], n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_srl_r(uint x) {
  bool c = r[x] & 0x01;
  r[x] >>= 1;
  r.f.z = r[x] == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

auto LR35902::op_srl_hl() {
  uint8 n = read(r[HL]);
  bool c = n & 0x01;
  n >>= 1;
  write(r[HL], n);
  r.f.z = n == 0;
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = c;
}

//single-bit commands

auto LR35902::op_bit_n_r(uint b, uint x) {
  r.f.z = (r[x] & (1 << b)) == 0;
  r.f.n = 0;
  r.f.h = 1;
}

auto LR35902::op_bit_n_hl(uint b) {
  uint8 n = read(r[HL]);
  r.f.z = (n & (1 << b)) == 0;
  r.f.n = 0;
  r.f.h = 1;
}

auto LR35902::op_set_n_r(uint b, uint x) {
  r[x] |= 1 << b;
}

auto LR35902::op_set_n_hl(uint b) {
  uint8 n = read(r[HL]);
  n |= 1 << b;
  write(r[HL], n);
}

auto LR35902::op_res_n_r(uint b, uint x) {
  r[x] &= ~(1 << b);
}

auto LR35902::op_res_n_hl(uint b) {
  uint n = read(r[HL]);
  n &= ~(1 << b);
  write(r[HL], n);
}

//control commands

auto LR35902::op_ccf() {
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = !r.f.c;
}

auto LR35902::op_scf() {
  r.f.n = 0;
  r.f.h = 0;
  r.f.c = 1;
}

auto LR35902::op_nop() {
}

auto LR35902::op_halt() {
  r.halt = true;
  while(r.halt) io();
}

auto LR35902::op_stop() {
  if(stop()) return;
  r.stop = true;
  while(r.stop) io();
}

auto LR35902::op_di() {
  r.ime = 0;
}

auto LR35902::op_ei() {
  r.ei = true;
//r.ime = 1;
}

//jump commands

auto LR35902::op_jp_nn() {
  uint8 lo = read(r[PC]++);
  uint8 hi = read(r[PC]++);
  r[PC] = (hi << 8) | (lo << 0);
  io();
}

auto LR35902::op_jp_hl() {
  r[PC] = r[HL];
}

auto LR35902::op_jp_f_nn(uint x, bool y) {
  uint8 lo = read(r[PC]++);
  uint8 hi = read(r[PC]++);
  if(r.f[x] == y) {
    r[PC] = (hi << 8) | (lo << 0);
    io();
  }
}

auto LR35902::op_jr_n() {
  int8 n = read(r[PC]++);
  r[PC] += n;
  io();
}

auto LR35902::op_jr_f_n(uint x, bool y) {
  int8 n = read(r[PC]++);
  if(r.f[x] == y) {
    r[PC] += n;
    io();
  }
}

auto LR35902::op_call_nn() {
  uint8 lo = read(r[PC]++);
  uint8 hi = read(r[PC]++);
  io();
  write(--r[SP], r[PC] >> 8);
  write(--r[SP], r[PC] >> 0);
  r[PC] = (hi << 8) | (lo << 0);
}

auto LR35902::op_call_f_nn(uint x, bool y) {
  uint8 lo = read(r[PC]++);
  uint8 hi = read(r[PC]++);
  if(r.f[x] == y) {
    io();
    write(--r[SP], r[PC] >> 8);
    write(--r[SP], r[PC] >> 0);
    r[PC] = (hi << 8) | (lo << 0);
  }
}

auto LR35902::op_ret() {
  uint8 lo = read(r[SP]++);
  uint8 hi = read(r[SP]++);
  r[PC] = (hi << 8) | (lo << 0);
  io();
}

auto LR35902::op_ret_f(uint x, bool y) {
  io();
  if(r.f[x] == y) {
    uint8 lo = read(r[SP]++);
    uint8 hi = read(r[SP]++);
    r[PC] = (hi << 8) | (lo << 0);
    io();
  }
}

auto LR35902::op_reti() {
  uint8 lo = read(r[SP]++);
  uint8 hi = read(r[SP]++);
  r[PC] = (hi << 8) | (lo << 0);
  io();
  r.ime = 1;
}

auto LR35902::op_rst_n(uint n) {
  io();
  write(--r[SP], r[PC] >> 8);
  write(--r[SP], r[PC] >> 0);
  r[PC] = n;
}