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 namespace PC6001 {
  15
  16 void DISPLAY::reset()
  17 {
  18         vram_ptr = ram_ptr + 0xe000;
  19 }
  20
  21 void DISPLAY::write_io8(uint32_t addr, uint32_t data)
  22 {
  23         unsigned int VRAMHead[4] = { 0xc000, 0xe000, 0x8000, 0xa000 };
  24         uint16_t port=(addr & 0x00ff);
  25
  26         switch (port) {
  27         case 0xB0:
  28                 vram_ptr = (ram_ptr + VRAMHead[(data & 0x06) >> 1]);
  29                 d_timer->set_portB0(data);
  30                 break;
  31         }
  32 }
  33
  34 void DISPLAY::draw_screen()
  35 {
  36         d_vdp->write_signal(SIG_MC6847_AG, *vram_ptr, 0x80);
  37         d_vdp->write_signal(SIG_MC6847_GM, *vram_ptr >> 4, 1);
  38         d_vdp->write_signal(SIG_MC6847_GM, *vram_ptr >> 2, 2);
  39         d_vdp->write_signal(SIG_MC6847_GM, *vram_ptr >> 0, 4);
  40         d_vdp->write_signal(SIG_MC6847_CSS, *vram_ptr, 0x02);
  41         if(*vram_ptr & 0x80) {
  42                 d_vdp->set_vram_ptr(vram_ptr + 0x200, 0x1800);
  43         } else {
  44                 d_vdp->set_vram_ptr(vram_ptr, 0x1800);
  45         }
  46         d_vdp->draw_screen();
  47 }
  48
  49 #define STATE_VERSION   1
  50
  51 bool DISPLAY::process_state(FILEIO* state_fio, bool loading)
  52 {
  53         if(!state_fio->StateCheckUint32(STATE_VERSION)) {
  54                 return false;
  55         }
  56         if(!state_fio->StateCheckInt32(this_device_id)) {
  57                 return false;
  58         }
  59         if(loading) {
  60                 vram_ptr = ram_ptr + state_fio->FgetInt32_LE();
  61         } else {
  62                 state_fio->FputInt32_LE((int)(vram_ptr - ram_ptr));
  63         }
  64         return true;
  65 }
  66
  67 }