public static int rb(int addr)
{
switch (addr & 0xF000)
{
// ROM bank 0
case 0x0000:
if (MMU._inbios)
{
if (addr < 0x0100)
{
return(MMU._bios[addr]);
}
else if (Z80._r.pc == 0x0100)
{
MMU._inbios = false;
LOG.@out("MMU", "Leaving BIOS.");
return(rb(addr));
}
}
else
{
return(MMU._rom[addr]);
}
break;
case 0x1000:
case 0x2000:
case 0x3000:
return(MMU._rom[addr]);
// ROM bank 1
case 0x4000:
case 0x5000:
case 0x6000:
case 0x7000:
return(MMU._rom[MMU._romoffs + (addr & 0x3FFF)]);
// VRAM
case 0x8000:
case 0x9000:
return(GPU._vram[addr & 0x1FFF]);
// External RAM
case 0xA000:
case 0xB000:
return(MMU._eram[MMU._ramoffs + (addr & 0x1FFF)]);
// Work RAM and echo
case 0xC000:
case 0xD000:
case 0xE000:
return(MMU._wram[addr & 0x1FFF]);
// Everything else
case 0xF000:
switch (addr & 0x0F00)
{
// Echo RAM
case 0x000:
case 0x100:
case 0x200:
case 0x300:
case 0x400:
case 0x500:
case 0x600:
case 0x700:
case 0x800:
case 0x900:
case 0xA00:
case 0xB00:
case 0xC00:
case 0xD00:
return(MMU._wram[addr & 0x1FFF]);
// OAM
case 0xE00:
return(((addr & 0xFF) < 0xA0) ? GPU._oam[addr & 0xFF] : 0);
// Zeropage RAM, I/O, interrupts
case 0xF00:
if (addr == 0xFFFF)
{
return(MMU._ie);
}
else if (addr > 0xFF7F)
{
return(MMU._zram[addr & 0x7F]);
}
else
{
switch (addr & 0xF0)
{
case 0x00:
switch (addr & 0xF)
{
case 0: return(KEY.rb()); // JOYP
case 4:
case 5:
case 6:
case 7:
return(TIMER.rb(addr));
case 15: return(MMU._if); // Interrupt flags
default: return(0);
}
case 0x10:
case 0x20:
case 0x30:
return(0);
case 0x40:
case 0x50:
case 0x60:
case 0x70:
return(GPU.rb(addr));
}
}
break;
}
break;
}
throw new InvalidOperationException($"Unable to read address {addr}: Out of range.");
}
public static void Reset()
{
LOG.reset(); GPU.reset(); MMU.reset(); Z80.reset(); KEY.reset(); TIMER.reset();
Z80._r.pc = 0x100; MMU._inbios = true; Z80._r.sp = 0xFFFE; Z80._r.h = 0x01; Z80._r.l = 0x4D;
Z80._r.c = 0x13; Z80._r.e = 0xD8; Z80._r.a = 1;
}
public static void reset()
{
GPU._vram = new int[8192];
GPU._oam = new int[160];
for (int i = 0; i < 4; i++)
{
GPU._palette.bg[i] = 255;
GPU._palette.obj0[i] = 255;
GPU._palette.obj1[i] = 255;
}
GPU._tilemap = new int[512, 8, 8];
LOG.@out("GPU", "Initialising screen.");
GPU._canvas = new int[160, 144];
for (int i = 0; i < GPU._scrn.data.Length; i++)
{
GPU._scrn.data[i] = 255;
}
CopyScrnToCanvas();
GPU._curline = 0;
GPU._curscan = 0;
GPU._linemode = 2;
GPU._modeclocks = 0;
GPU._yscrl = 0;
GPU._xscrl = 0;
GPU._raster = 0;
GPU._ints = 0;
GPU._lcdon = 0;
GPU._bgon = 0;
GPU._objon = 0;
GPU._winon = 0;
GPU._objsize = 0;
GPU._scanrow = new int[160];
for (int i = 0; i < 40; i++)
{
GPU._objdata[i] = new ObjData
{
y = -16,
x = -8,
tile = 0,
palette = 0,
yflip = 0,
xflip = 0,
prio = 0,
num = i
};
}
// Set to values expected by BIOS, to start
GPU._bgtilebase = 0x0000;
GPU._bgmapbase = 0x1800;
GPU._wintilebase = 0x1800; // TODO: doesn't seem to be used anywhere?
LOG.@out("GPU", "Reset.");
}