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A7800: cycle based DMA list fetching

This commit is contained in:
alyosha-tas 2018-11-23 10:20:52 -06:00
parent 572c7f34c8
commit af39f65b03
1 changed files with 104 additions and 64 deletions
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168
BizHawk.Emulation.Cores/Consoles/Atari/A7800Hawk/Maria.cs
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@ -71,6 +71,11 @@ namespace BizHawk.Emulation.Cores.Atari.A7800Hawk
public int header_counter;
public int header_pointer; // since headers could be 4 or 5 bytes, we need a seperate pointer
public ushort addr_t;
public int ch_size;
public int scan_index;
public int read_time;
public bool zero_hole; // the first DMA hole does not save cycles
// variables for drawing a pixel
int color;
@ -186,9 +191,8 @@ namespace BizHawk.Emulation.Cores.Atari.A7800Hawk
}
}
if (cycle == 428 && !sl_DMA_complete && do_dma && (DMA_phase == DMA_GRAPHICS || DMA_phase == DMA_HEADER))
if (cycle == 453 && !sl_DMA_complete && do_dma && (DMA_phase == DMA_GRAPHICS || DMA_phase == DMA_HEADER))
{
//Console.WriteLine(scanline);
if (current_DLL_offset == 0)
{
DMA_phase = DMA_SHUTDOWN_LAST;
@ -215,9 +219,10 @@ namespace BizHawk.Emulation.Cores.Atari.A7800Hawk
if (cycle == 133)
{
disp_mode = Core.Maria_regs[0x1C] & 0x3;
BG_latch_1 = Core.Maria_regs[0];
}
BG_latch_1 = Core.Maria_regs[0];
color = line_ram[local_GFX_index, pixel];
@ -434,101 +439,136 @@ namespace BizHawk.Emulation.Cores.Atari.A7800Hawk
{
if (DMA_phase_counter == 1)
{
ushort addr_t = 0;
addr_t = 0;
scan_index = 0;
read_time = 0;
zero_hole = false;
// in 5 byte mode, we first have to check if we are in direct or indirect mode
if (GFX_Objects[header_counter].ind_mode)
{
int ch_size = 0;
ch_size = 0;
if (Core.Maria_regs[0x1C].Bit(4))
{
graphics_read_time = 9 * GFX_Objects[header_counter].width;
graphics_read_time = 9;
ch_size = 2;
}
else
{
graphics_read_time = 6 * GFX_Objects[header_counter].width;
graphics_read_time = 6;
ch_size = 1;
}
// the address here is specified by CHAR_BASE maria registers
// ushort addr = (ushort)(GFX_Objects[header_counter].addr & 0xFF);
for (int i = 0; i < GFX_Objects[header_counter].width; i++)
{
addr_t = ReadMemory((ushort)(GFX_Objects[header_counter].addr + i));
addr_t |= (ushort)((Core.Maria_regs[0x14] + current_DLL_offset) << 8);
if (((current_DLL_H16 && addr_t.Bit(12)) || (current_DLL_H8 && addr_t.Bit(11))) && (addr_t >= 0x8000))
{
if (i * ch_size < 128)
{
GFX_Objects[header_counter].obj[i * ch_size] = 0;
}
if ((i * ch_size + 1 < 128) && (ch_size == 2))
{
GFX_Objects[header_counter].obj[i * ch_size + 1] = 0;
}
if (i != 0)
{
if (ch_size == 1)
{
graphics_read_time -= 6;
}
else
{
graphics_read_time -= 9;
}
}
}
else
{
if (i * ch_size < 128)
{
GFX_Objects[header_counter].obj[i * ch_size] = ReadMemory(addr_t);
fill_line_ram(GFX_Objects[header_counter].h_pos * 2, i, 0, ch_size, GFX_Objects[header_counter].obj[i * ch_size], GFX_Objects[header_counter].write_mode);
}
if (((i * ch_size + 1) < 128) && (ch_size == 2))
{
GFX_Objects[header_counter].obj[i * ch_size + 1] = ReadMemory((ushort)(addr_t + 1));
fill_line_ram(GFX_Objects[header_counter].h_pos * 2, i, 1, ch_size, GFX_Objects[header_counter].obj[i * ch_size + 1], GFX_Objects[header_counter].write_mode);
}
}
}
}
else
{
graphics_read_time = 3 * GFX_Objects[header_counter].width;
graphics_read_time = 3;
}
for (int i = 0; i < GFX_Objects[header_counter].width; i++)
if (graphics_read_time == 0)
{
// We have read the graphics data, for this header, now return to the header list
// This loop will continue until a header indicates its time to stop
DMA_phase = DMA_HEADER;
DMA_phase_counter = 0;
return;
}
}
if (read_time == 0)
{
bool skip = true;
while (skip)
{
if (GFX_Objects[header_counter].ind_mode)
{
addr_t = (ushort)(GFX_Objects[header_counter].addr + (current_DLL_offset << 8) + i);
addr_t = ReadMemory((ushort)(GFX_Objects[header_counter].addr + scan_index));
addr_t |= (ushort)((Core.Maria_regs[0x14] + current_DLL_offset) << 8);
}
else
{
addr_t = (ushort)(GFX_Objects[header_counter].addr + (current_DLL_offset << 8) + scan_index);
}
if (((current_DLL_H16 && addr_t.Bit(12)) || (current_DLL_H8 && addr_t.Bit(11))) && (addr_t >= 0x8000))
if (((current_DLL_H16 && addr_t.Bit(12)) || (current_DLL_H8 && addr_t.Bit(11))) && (addr_t >= 0x8000))
{
if (GFX_Objects[header_counter].ind_mode)
{
GFX_Objects[header_counter].obj[i] = 0;
if (i != 0)
{
graphics_read_time -= 3;
if (scan_index * ch_size < 128)
{
GFX_Objects[header_counter].obj[scan_index * ch_size] = 0;
}
if ((scan_index * ch_size + 1 < 128) && (ch_size == 2))
{
GFX_Objects[header_counter].obj[scan_index * ch_size + 1] = 0;
}
}
else
{
GFX_Objects[header_counter].obj[i] = ReadMemory(addr_t);
fill_line_ram(GFX_Objects[header_counter].h_pos * 2, i, 0, 1, GFX_Objects[header_counter].obj[i], GFX_Objects[header_counter].write_mode);
GFX_Objects[header_counter].obj[scan_index] = 0;
}
if (scan_index == 0)
{
skip = false;
zero_hole = true;
}
else
{
scan_index++;
if (scan_index == GFX_Objects[header_counter].width)
{
skip = false;
}
}
}
else
{
skip = false;
}
}
}
if (DMA_phase_counter == graphics_read_time || graphics_read_time == 0)
read_time++;
if (read_time == graphics_read_time)
{
if (!zero_hole)
{
// in 5 byte mode, we first have to check if we are in direct or indirect mode
if (GFX_Objects[header_counter].ind_mode)
{
if (scan_index * ch_size < 128)
{
GFX_Objects[header_counter].obj[scan_index * ch_size] = ReadMemory(addr_t);
fill_line_ram(GFX_Objects[header_counter].h_pos * 2, scan_index, 0, ch_size, GFX_Objects[header_counter].obj[scan_index * ch_size], GFX_Objects[header_counter].write_mode);
}
if (((scan_index * ch_size + 1) < 128) && (ch_size == 2))
{
GFX_Objects[header_counter].obj[scan_index * ch_size + 1] = ReadMemory((ushort)(addr_t + 1));
fill_line_ram(GFX_Objects[header_counter].h_pos * 2, scan_index, 1, ch_size, GFX_Objects[header_counter].obj[scan_index * ch_size + 1], GFX_Objects[header_counter].write_mode);
}
}
else
{
GFX_Objects[header_counter].obj[scan_index] = ReadMemory(addr_t);
fill_line_ram(GFX_Objects[header_counter].h_pos * 2, scan_index, 0, 1, GFX_Objects[header_counter].obj[scan_index], GFX_Objects[header_counter].write_mode);
}
}
zero_hole = false;
scan_index++;
read_time = 0;
}
if (scan_index == GFX_Objects[header_counter].width)
{
// We have read the graphics data, for this header, now return to the header list
// This loop will continue until a header indicates its time to stop
DMA_phase = DMA_HEADER;
DMA_phase_counter = 0;
}
return;
}