main.c

psp上的GBA模拟器

        affine_reference_x[0] =
         (s32)(address32(io_registers, 0x28) << 4) >> 4;
        affine_reference_y[0] =
         (s32)(address32(io_registers, 0x2C) << 4) >> 4;
        affine_reference_x[1] =
         (s32)(address32(io_registers, 0x38) << 4) >> 4;
        affine_reference_y[1] =
         (s32)(address32(io_registers, 0x3C) << 4) >> 4;

        for(i = 0; i < 4; i++)
        {
          if(dma[i].start_type == DMA_START_VBLANK)
            dma_transfer(dma + i);
        }
      }
      else

      if(vcount == 228)
      {
        // Transition from vblank to next screen
        dispstat &= ~0x01;
        frame_ticks++;

#ifndef PSP_BUILD
/*        printf("frame update (%x), %d instructions total, %d RAM flushes\n",
         reg[REG_PC], instruction_count - last_frame, flush_ram_count);
        last_frame = instruction_count;
        print_memory_stats(&memory_reads_u8, memory_region_access_read_u8,
         "unsigned 8bit read");
        print_memory_stats(&memory_reads_s8, memory_region_access_read_s8,
         "signed 8bit read");
        print_memory_stats(&memory_reads_u16, memory_region_access_read_u16,
         "unsigned 16bit read");
        print_memory_stats(&memory_reads_s16, memory_region_access_read_s16,
         "signed 16bit read");
        print_memory_stats(&memory_reads_u32, memory_region_access_read_u32,
         "32bit read");
        print_memory_stats(&memory_writes_u8, memory_region_access_write_u8,
         "8bit write");
        print_memory_stats(&memory_writes_u16, memory_region_access_write_u16,
         "16bit write");
        print_memory_stats(&memory_writes_u32, memory_region_access_write_u32,
         "32bit write");
        printf("%d gbc audio updates\n", gbc_update_count);
        printf("%d oam updates\n", oam_update_count); */
        gbc_update_count = 0;
        oam_update_count = 0;
        flush_ram_count = 0;
#endif

        if(update_input())
          return execute_cycles;

        update_gbc_sound(cpu_ticks);
        synchronize();
        update_screen();
        if(update_backup_flag)
          update_backup();

        process_cheats();

        vcount = 0;
      }

      if(vcount == (dispstat >> 8))
      {
        // vcount trigger
        dispstat |= 0x04;
        if(dispstat & 0x20)
        {
          irq_raised |= IRQ_VCOUNT;
        }
      }
      else
      {
        dispstat &= ~0x04;
      }

      io_registers[REG_VCOUNT] = vcount;
    }
    io_registers[REG_DISPSTAT] = dispstat;
  }

  if(irq_raised)
    raise_interrupt(irq_raised);

  execute_cycles = video_count;

  check_timer(0);
  check_timer(1);
  check_timer(2);
  check_timer(3);

  return execute_cycles;
}

u64 last_screen_timestamp = 0;
u32 frame_speed = 15000;

#ifdef PSP_BUILD

u32 real_frame_count = 0;
u32 virtual_frame_count = 0;
u32 num_skipped_frames = 0;

void vblank_interrupt_handler(u32 sub, u32 *parg)
{
  real_frame_count++;
}

void synchronize()
{
  char char_buffer[64];
  u64 new_ticks, time_delta;
  s32 used_frameskip = frameskip_value;

  if(!synchronize_flag)
  {
    print_string("--FF--", 0xFFFF, 0x000, 0, 0);
    used_frameskip = 4;
    virtual_frame_count = real_frame_count - 1;
  }

  skip_next_frame = 0;

  virtual_frame_count++;

  if(real_frame_count >= virtual_frame_count)
  {
    if((real_frame_count > virtual_frame_count) &&
     (current_frameskip_type == auto_frameskip) &&
     (num_skipped_frames < frameskip_value))
    {
      skip_next_frame = 1;
      num_skipped_frames++;
    }
    else
    {
      virtual_frame_count = real_frame_count;
      num_skipped_frames = 0;
    }

    // Here so that the home button return will eventually work.
    // If it's not running fullspeed anyway this won't really hurt
    // it much more.

    delay_us(1);
  }
  else
  {
    if(synchronize_flag)
      sceDisplayWaitVblankStart();
  }

  if(current_frameskip_type == manual_frameskip)
  {
    frameskip_counter = (frameskip_counter + 1) %
     (used_frameskip + 1);
    if(random_skip)
    {
      if(frameskip_counter != (rand() % (used_frameskip + 1)))
        skip_next_frame = 1;
    }
    else
    {
      if(frameskip_counter)
        skip_next_frame = 1;
    }
  }

/*  sprintf(char_buffer, "%08d %08d %d %d %d\n",
   real_frame_count, virtual_frame_count, num_skipped_frames,
   real_frame_count - virtual_frame_count, skip_next_frame);
  print_string(char_buffer, 0xFFFF, 0x0000, 0, 10); */

/*
    sprintf(char_buffer, "%02d %02d %06d %07d", frameskip, (u32)ms_needed,
     ram_translation_ptr - ram_translation_cache, rom_translation_ptr -
     rom_translation_cache);
    print_string(char_buffer, 0xFFFF, 0x0000, 0, 0);
*/
}

#else

u32 ticks_needed_total = 0;
float us_needed = 0.0;
u32 frames = 0;
const u32 frame_interval = 60;

void synchronize()
{
  u64 new_ticks;
  u64 time_delta;
  char char_buffer[64];

  get_ticks_us(&new_ticks);
  time_delta = new_ticks - last_screen_timestamp;
  last_screen_timestamp = new_ticks;
  ticks_needed_total += time_delta;

  skip_next_frame = 0;

  if((time_delta < frame_speed) && synchronize_flag)
  {
    delay_us(frame_speed - time_delta);
  }

  frames++;

  if(frames == frame_interval)
  {
    us_needed = (float)ticks_needed_total / frame_interval;
    ticks_needed_total = 0;
    frames = 0;
  }

  if(current_frameskip_type == manual_frameskip)
  {
    frameskip_counter = (frameskip_counter + 1) %
     (frameskip_value + 1);
    if(random_skip)
    {
      if(frameskip_counter != (rand() % (frameskip_value + 1)))
        skip_next_frame = 1;
    }
    else
    {
      if(frameskip_counter)
        skip_next_frame = 1;
    }
  }

  if(synchronize_flag == 0)
    print_string("--FF--", 0xFFFF, 0x000, 0, 0);

  sprintf(char_buffer, "gpSP: %.1fms %.1ffps", us_needed / 1000.0,
   1000000.0 / us_needed);
  SDL_WM_SetCaption(char_buffer, "gpSP");

/*
    sprintf(char_buffer, "%02d %02d %06d %07d", frameskip, (u32)ms_needed,
     ram_translation_ptr - ram_translation_cache, rom_translation_ptr -
     rom_translation_cache);
    print_string(char_buffer, 0xFFFF, 0x0000, 0, 0);
*/
}

#endif

void quit()
{
  if(!update_backup_flag)
    update_backup_force();

  sound_exit();

#ifdef PSP_BUILD
  sceKernelExitGame();
#else
  SDL_Quit();
  exit(0);
#endif
}

void reset_gba()
{
  init_main();
  init_memory();
  init_cpu();
  reset_sound();
}

#ifdef PSP_BUILD

u32 file_length(u8 *filename, s32 dummy)
{
  SceIoStat stats;
  sceIoGetstat(filename, &stats);
  return stats.st_size;
}

void delay_us(u32 us_count)
{
  sceKernelDelayThread(us_count);
}

void get_ticks_us(u64 *tick_return)
{
  u64 ticks;
  sceRtcGetCurrentTick(&ticks);

  *tick_return = (ticks * 1000000) / sceRtcGetTickResolution();
}

#else

u32 file_length(u8 *dummy, FILE *fp)
{
  u32 length;

  fseek(fp, 0, SEEK_END);
  length = ftell(fp);
  fseek(fp, 0, SEEK_SET);

  return length;
}

void delay_us(u32 us_count)
{
  SDL_Delay(us_count / 1000);
}

void get_ticks_us(u64 *ticks_return)
{
  *ticks_return = (SDL_GetTicks() * 1000);
}

#endif

void change_ext(u8 *src, u8 *buffer, u8 *extension)
{
  u8 *dot_position;
  strcpy(buffer, src);
  dot_position = strrchr(buffer, '.');

  if(dot_position)
    strcpy(dot_position, extension);
}

#define main_savestate_builder(type)                                          \
void main_##type##_savestate(file_tag_type savestate_file)                    \
{                                                                             \
  file_##type##_variable(savestate_file, cpu_ticks);                          \
  file_##type##_variable(savestate_file, execute_cycles);                     \
  file_##type##_variable(savestate_file, video_count);                        \
  file_##type##_array(savestate_file, timer);                                 \
}                                                                             \

main_savestate_builder(read);
main_savestate_builder(write_mem);

void print_out(u32 address, u32 pc)
{
  char buffer[256];
  sprintf(buffer, "patching from gp8 %x", address);
  print_string(buffer, 0xFFFF, 0x0000, 0, 0);
  update_screen();
  delay_us(5000000);
}