source/src/vm/pc6001/display.cpp

   1 /*
   2         NEC PC-6001 Emulator 'yaPC-6001'
   3
   4         Author : Takeda.Toshiya
   5         Date   : 2013.08.22-
   6
   7         [ display ]
   8 */
   9
  10 #include "display.h"
  11 #include "timer.h"
  12 #include "../mc6847.h"
  13
  14 void DISPLAY::reset()
  15 {
  16         vram_ptr = ram_ptr + 0xe000;
  17 }
  18
  19 void DISPLAY::write_io8(uint32_t addr, uint32_t data)
  20 {
  21         unsigned int VRAMHead[4] = { 0xc000, 0xe000, 0x8000, 0xa000 };
  22         uint16_t port=(addr & 0x00ff);
  23
  24         switch (port) {
  25         case 0xB0:
  26                 vram_ptr = (ram_ptr + VRAMHead[(data & 0x06) >> 1]);
  27                 d_timer->set_portB0(data);
  28                 break;
  29         }
  30 }
  31
  32 void DISPLAY::draw_screen()
  33 {
  34         d_vdp->write_signal(SIG_MC6847_AG, *vram_ptr, 0x80);
  35         d_vdp->write_signal(SIG_MC6847_GM, *vram_ptr >> 4, 1);
  36         d_vdp->write_signal(SIG_MC6847_GM, *vram_ptr >> 2, 2);
  37         d_vdp->write_signal(SIG_MC6847_GM, *vram_ptr >> 0, 4);
  38         d_vdp->write_signal(SIG_MC6847_CSS, *vram_ptr, 0x02);
  39         if(*vram_ptr & 0x80) {
  40                 d_vdp->set_vram_ptr(vram_ptr + 0x200, 0x1800);
  41         } else {
  42                 d_vdp->set_vram_ptr(vram_ptr, 0x1800);
  43         }
  44         d_vdp->draw_screen();
  45 }
  46
  47 #define STATE_VERSION   1
  48
  49 bool DISPLAY::process_state(FILEIO* state_fio, bool loading)
  50 {
  51         if(!state_fio->StateCheckUint32(STATE_VERSION)) {
  52                 return false;
  53         }
  54         if(!state_fio->StateCheckInt32(this_device_id)) {
  55                 return false;
  56         }
  57         if(loading) {
  58                 vram_ptr = ram_ptr + state_fio->FgetInt32_LE();
  59         } else {
  60                 state_fio->FputInt32_LE((int)(vram_ptr - ram_ptr));
  61         }
  62         return true;
  63 }