source/src/vm/bubcom80/membus.cpp

   1 /*
   2         Systems Formulate BUBCOM80 Emulator 'eBUBCOM80'
   3
   4         Author : Takeda.Toshiya
   5         Date   : 2018.05.08-
   6
   7         [ memory bus ]
   8 */
   9
  10 #include "membus.h"
  11
  12 namespace BUBCOM80 {
  13 void MEMBUS::initialize()
  14 {
  15         MEMORY::initialize();
  16
  17         memset(ram, 0x00, sizeof(ram));
  18         memset(boot, 0xff, sizeof(boot));
  19         memset(basic, 0xff, sizeof(basic));
  20
  21         if(!read_bios(_T("IPL.ROM"), boot, sizeof(boot))) {
  22                 read_bios(_T("BOOT.ROM"), boot, sizeof(boot));
  23         }
  24         read_bios(_T("BASIC.ROM"), basic, sizeof(basic));
  25
  26         set_memory_rw(0x0000, 0xffff, ram);
  27 }
  28
  29 void MEMBUS::reset()
  30 {
  31         MEMORY::reset();
  32
  33         basic_addr.d = 0;
  34         ram_selected = false;
  35         update_bank();
  36 }
  37
  38 void MEMBUS::write_io8(uint32_t addr, uint32_t data)
  39 {
  40         switch(addr) {
  41         case 0x0c:
  42                 basic_addr.b.l = data;
  43                 break;
  44         case 0x0d:
  45                 basic_addr.b.h = data;
  46                 break;
  47         case 0x0e:
  48                 // error code ???
  49                 break;
  50         case 0x80:
  51                 ram_selected = ((data & 0x80) != 0);
  52                 update_bank();
  53                 break;
  54         }
  55 }
  56
  57 uint32_t MEMBUS::read_io8(uint32_t addr)
  58 {
  59         switch(addr) {
  60         case 0x0c:
  61                 return basic[basic_addr.w.l];
  62         }
  63         return 0xff;
  64 }
  65
  66 void MEMBUS::write_dma_data8(uint32_t addr, uint32_t data)
  67 {
  68         ram[addr & 0xffff] = data;
  69 }
  70
  71 uint32_t MEMBUS::read_dma_data8(uint32_t addr)
  72 {
  73         return ram[addr & 0xffff];
  74 }
  75
  76 void MEMBUS::update_bank()
  77 {
  78         set_memory_r(0x0000, 0x07ff, ram_selected ? ram : boot);
  79 }
  80
  81 #define STATE_VERSION   1
  82
  83 bool MEMBUS::process_state(FILEIO* state_fio, bool loading)
  84 {
  85         if(!state_fio->StateCheckUint32(STATE_VERSION)) {
  86                 return false;
  87         }
  88         if(!state_fio->StateCheckInt32(this_device_id)) {
  89                 return false;
  90         }
  91         if(!MEMORY::process_state(state_fio, loading)) {
  92                 return false;
  93         }
  94         state_fio->StateBuffer(ram, sizeof(ram), 1);
  95         state_fio->StateUint32(basic_addr.d);
  96         state_fio->StateBool(ram_selected);
  97
  98         // post process
  99         if(loading) {
 100                 update_bank();
 101         }
 102         return true;
 103 }
 104 }