bsnes/higan/fc/ppu/ppu.cpp

490 lines
13 KiB
C++

#include <fc/fc.hpp>
namespace Famicom {
PPU ppu;
#include "video.cpp"
#include "serialization.cpp"
auto PPU::Main() -> void {
ppu.main();
}
auto PPU::main() -> void {
while(true) {
if(scheduler.sync == Scheduler::SynchronizeMode::PPU) {
scheduler.exit(Scheduler::ExitReason::SynchronizeEvent);
}
raster_scanline();
}
}
auto PPU::tick() -> void {
if(status.ly == 240 && status.lx == 340) status.nmi_hold = 1;
if(status.ly == 241 && status.lx == 0) status.nmi_flag = status.nmi_hold;
if(status.ly == 241 && status.lx == 2) cpu.set_nmi_line(status.nmi_enable && status.nmi_flag);
if(status.ly == 260 && status.lx == 340) status.sprite_zero_hit = 0, status.sprite_overflow = 0;
if(status.ly == 260 && status.lx == 340) status.nmi_hold = 0;
if(status.ly == 261 && status.lx == 0) status.nmi_flag = status.nmi_hold;
if(status.ly == 261 && status.lx == 2) cpu.set_nmi_line(status.nmi_enable && status.nmi_flag);
clock += 4;
if(clock >= 0) co_switch(cpu.thread);
status.lx++;
}
auto PPU::scanline() -> void {
status.lx = 0;
if(++status.ly == 262) {
status.ly = 0;
frame();
}
cartridge.scanline(status.ly);
}
auto PPU::frame() -> void {
status.field ^= 1;
scheduler.exit(Scheduler::ExitReason::FrameEvent);
}
auto PPU::power() -> void {
}
auto PPU::reset() -> void {
create(PPU::Main, 21477272);
status.mdr = 0x00;
status.field = 0;
status.ly = 0;
status.bus_data = 0x00;
status.address_latch = 0;
status.vaddr = 0x0000;
status.taddr = 0x0000;
status.xaddr = 0x00;
status.nmi_hold = 0;
status.nmi_flag = 0;
//$2000
status.nmi_enable = false;
status.master_select = 0;
status.sprite_size = 0;
status.bg_addr = 0x0000;
status.sprite_addr = 0x0000;
status.vram_increment = 1;
//$2001
status.emphasis = 0;
status.sprite_enable = false;
status.bg_enable = false;
status.sprite_edge_enable = false;
status.bg_edge_enable = false;
status.grayscale = false;
//$2002
status.sprite_zero_hit = false;
status.sprite_overflow = false;
//$2003
status.oam_addr = 0x00;
for(auto& n : buffer) n = 0;
for(auto& n : ciram ) n = 0;
for(auto& n : cgram ) n = 0;
for(auto& n : oam ) n = 0;
}
auto PPU::read(uint16 addr) -> uint8 {
uint8 result = 0x00;
switch(addr & 7) {
case 2: //PPUSTATUS
result |= status.nmi_flag << 7;
result |= status.sprite_zero_hit << 6;
result |= status.sprite_overflow << 5;
result |= status.mdr & 0x1f;
status.address_latch = 0;
status.nmi_hold = 0;
cpu.set_nmi_line(status.nmi_flag = 0);
break;
case 4: //OAMDATA
result = oam[status.oam_addr];
if((status.oam_addr & 3) == 3) result &= 0xe3;
break;
case 7: //PPUDATA
if(raster_enable() && (status.ly <= 240 || status.ly == 261)) return 0x00;
addr = status.vaddr & 0x3fff;
if(addr <= 0x1fff) {
result = status.bus_data;
status.bus_data = cartridge.chr_read(addr);
} else if(addr <= 0x3eff) {
result = status.bus_data;
status.bus_data = cartridge.chr_read(addr);
} else if(addr <= 0x3fff) {
result = cgram_read(addr);
status.bus_data = cartridge.chr_read(addr);
}
status.vaddr += status.vram_increment;
break;
}
return result;
}
auto PPU::write(uint16 addr, uint8 data) -> void {
status.mdr = data;
switch(addr & 7) {
case 0: //PPUCTRL
status.nmi_enable = data & 0x80;
status.master_select = data & 0x40;
status.sprite_size = data & 0x20;
status.bg_addr = (data & 0x10) ? 0x1000 : 0x0000;
status.sprite_addr = (data & 0x08) ? 0x1000 : 0x0000;
status.vram_increment = (data & 0x04) ? 32 : 1;
status.taddr = (status.taddr & 0x73ff) | ((data & 0x03) << 10);
cpu.set_nmi_line(status.nmi_enable && status.nmi_hold && status.nmi_flag);
return;
case 1: //PPUMASK
status.emphasis = data >> 5;
status.sprite_enable = data & 0x10;
status.bg_enable = data & 0x08;
status.sprite_edge_enable = data & 0x04;
status.bg_edge_enable = data & 0x02;
status.grayscale = data & 0x01;
return;
case 2: //PPUSTATUS
return;
case 3: //OAMADDR
status.oam_addr = data;
return;
case 4: //OAMDATA
oam[status.oam_addr++] = data;
return;
case 5: //PPUSCROLL
if(status.address_latch == 0) {
status.xaddr = data & 0x07;
status.taddr = (status.taddr & 0x7fe0) | (data >> 3);
} else {
status.taddr = (status.taddr & 0x0c1f) | ((data & 0x07) << 12) | ((data >> 3) << 5);
}
status.address_latch ^= 1;
return;
case 6: //PPUADDR
if(status.address_latch == 0) {
status.taddr = (status.taddr & 0x00ff) | ((data & 0x3f) << 8);
} else {
status.taddr = (status.taddr & 0x7f00) | data;
status.vaddr = status.taddr;
}
status.address_latch ^= 1;
return;
case 7: //PPUDATA
if(raster_enable() && (status.ly <= 240 || status.ly == 261)) return;
addr = status.vaddr & 0x3fff;
if(addr <= 0x1fff) {
cartridge.chr_write(addr, data);
} else if(addr <= 0x3eff) {
cartridge.chr_write(addr, data);
} else if(addr <= 0x3fff) {
cgram_write(addr, data);
}
status.vaddr += status.vram_increment;
return;
}
}
auto PPU::ciram_read(uint16 addr) -> uint8 {
return ciram[addr & 0x07ff];
}
auto PPU::ciram_write(uint16 addr, uint8 data) -> void {
ciram[addr & 0x07ff] = data;
}
auto PPU::cgram_read(uint16 addr) -> uint8 {
if((addr & 0x13) == 0x10) addr &= ~0x10;
uint8 data = cgram[addr & 0x1f];
if(status.grayscale) data &= 0x30;
return data;
}
auto PPU::cgram_write(uint16 addr, uint8 data) -> void {
if((addr & 0x13) == 0x10) addr &= ~0x10;
cgram[addr & 0x1f] = data;
}
//
//vaddr = 0yyy VHYY YYYX XXXX
//yyy = fine Yscroll (y:d0-d2)
//V = V nametable (y:d8)
//H = H nametable (x:d8)
//YYYYY = Y nametable (y:d3-d7)
//XXXXX = X nametable (x:d3-d7)
auto PPU::raster_enable() const -> bool {
return (status.bg_enable || status.sprite_enable);
}
auto PPU::nametable_addr() const -> uint {
return 0x2000 + (status.vaddr & 0x0c00);
}
auto PPU::scrollx() const -> uint {
return ((status.vaddr & 0x1f) << 3) | status.xaddr;
}
auto PPU::scrolly() const -> uint {
return (((status.vaddr >> 5) & 0x1f) << 3) | ((status.vaddr >> 12) & 7);
}
auto PPU::sprite_height() const -> uint {
return status.sprite_size == 0 ? 8 : 16;
}
//
auto PPU::chr_load(uint16 addr) -> uint8 {
if(raster_enable() == false) return 0x00;
return cartridge.chr_read(addr);
}
//
auto PPU::scrollx_increment() -> void {
if(raster_enable() == false) return;
status.vaddr = (status.vaddr & 0x7fe0) | ((status.vaddr + 0x0001) & 0x001f);
if((status.vaddr & 0x001f) == 0x0000) {
status.vaddr ^= 0x0400;
}
}
auto PPU::scrolly_increment() -> void {
if(raster_enable() == false) return;
status.vaddr = (status.vaddr & 0x0fff) | ((status.vaddr + 0x1000) & 0x7000);
if((status.vaddr & 0x7000) == 0x0000) {
status.vaddr = (status.vaddr & 0x7c1f) | ((status.vaddr + 0x0020) & 0x03e0);
if((status.vaddr & 0x03e0) == 0x03c0) { //0x03c0 == 30 << 5; 30 * 8 = 240
status.vaddr &= 0x7c1f;
status.vaddr ^= 0x0800;
}
}
}
//
auto PPU::raster_pixel() -> void {
uint32* output = buffer + status.ly * 256;
uint mask = 0x8000 >> (status.xaddr + (status.lx & 7));
uint palette = 0, object_palette = 0;
bool object_priority = 0;
palette |= (raster.tiledatalo & mask) ? 1 : 0;
palette |= (raster.tiledatahi & mask) ? 2 : 0;
if(palette) {
uint attr = raster.attribute;
if(mask >= 256) attr >>= 2;
palette |= (attr & 3) << 2;
}
if(status.bg_enable == false) palette = 0;
if(status.bg_edge_enable == false && status.lx < 8) palette = 0;
if(status.sprite_enable == true)
for(int sprite = 7; sprite >= 0; sprite--) {
if(status.sprite_edge_enable == false && status.lx < 8) continue;
if(raster.oam[sprite].id == 64) continue;
uint spritex = status.lx - raster.oam[sprite].x;
if(spritex >= 8) continue;
if(raster.oam[sprite].attr & 0x40) spritex ^= 7;
uint mask = 0x80 >> spritex;
uint sprite_palette = 0;
sprite_palette |= (raster.oam[sprite].tiledatalo & mask) ? 1 : 0;
sprite_palette |= (raster.oam[sprite].tiledatahi & mask) ? 2 : 0;
if(sprite_palette == 0) continue;
if(raster.oam[sprite].id == 0 && palette && status.lx != 255) status.sprite_zero_hit = 1;
sprite_palette |= (raster.oam[sprite].attr & 3) << 2;
object_priority = raster.oam[sprite].attr & 0x20;
object_palette = 16 + sprite_palette;
}
if(object_palette) {
if(palette == 0 || object_priority == 0) palette = object_palette;
}
if(raster_enable() == false) palette = 0;
output[status.lx] = (status.emphasis << 6) | cgram_read(palette);
}
auto PPU::raster_sprite() -> void {
if(raster_enable() == false) return;
uint n = raster.oam_iterator++;
int ly = (status.ly == 261 ? -1 : status.ly);
uint y = ly - oam[(n * 4) + 0];
if(y >= sprite_height()) return;
if(raster.oam_counter == 8) {
status.sprite_overflow = 1;
return;
}
raster.soam[raster.oam_counter].id = n;
raster.soam[raster.oam_counter].y = oam[(n * 4) + 0];
raster.soam[raster.oam_counter].tile = oam[(n * 4) + 1];
raster.soam[raster.oam_counter].attr = oam[(n * 4) + 2];
raster.soam[raster.oam_counter].x = oam[(n * 4) + 3];
raster.oam_counter++;
}
auto PPU::raster_scanline() -> void {
if((status.ly >= 240 && status.ly <= 260)) {
for(auto x : range(341)) tick();
return scanline();
}
raster.oam_iterator = 0;
raster.oam_counter = 0;
for(auto n : range(8)) {
raster.soam[n].id = 64;
raster.soam[n].y = 0xff;
raster.soam[n].tile = 0xff;
raster.soam[n].attr = 0xff;
raster.soam[n].x = 0xff;
raster.soam[n].tiledatalo = 0;
raster.soam[n].tiledatahi = 0;
}
for(uint tile : range(32)) { // 0-255
uint nametable = chr_load(0x2000 | (status.vaddr & 0x0fff));
uint tileaddr = status.bg_addr + (nametable << 4) + (scrolly() & 7);
raster_pixel();
tick();
raster_pixel();
tick();
uint attribute = chr_load(0x23c0 | (status.vaddr & 0x0fc0) | ((scrolly() >> 5) << 3) | (scrollx() >> 5));
if(scrolly() & 16) attribute >>= 4;
if(scrollx() & 16) attribute >>= 2;
raster_pixel();
tick();
scrollx_increment();
if(tile == 31) scrolly_increment();
raster_pixel();
raster_sprite();
tick();
uint tiledatalo = chr_load(tileaddr + 0);
raster_pixel();
tick();
raster_pixel();
tick();
uint tiledatahi = chr_load(tileaddr + 8);
raster_pixel();
tick();
raster_pixel();
raster_sprite();
tick();
raster.nametable = (raster.nametable << 8) | nametable;
raster.attribute = (raster.attribute << 2) | (attribute & 3);
raster.tiledatalo = (raster.tiledatalo << 8) | tiledatalo;
raster.tiledatahi = (raster.tiledatahi << 8) | tiledatahi;
}
for(auto n : range(8)) raster.oam[n] = raster.soam[n];
for(uint sprite : range(8)) { //256-319
uint nametable = chr_load(0x2000 | (status.vaddr & 0x0fff));
tick();
if(raster_enable() && sprite == 0) status.vaddr = (status.vaddr & 0x7be0) | (status.taddr & 0x041f); //257
tick();
uint attribute = chr_load(0x23c0 | (status.vaddr & 0x0fc0) | ((scrolly() >> 5) << 3) | (scrollx() >> 5));
uint tileaddr = (sprite_height() == 8)
? status.sprite_addr + raster.oam[sprite].tile * 16
: ((raster.oam[sprite].tile & ~1) * 16) + ((raster.oam[sprite].tile & 1) * 0x1000);
tick();
tick();
uint spritey = (status.ly - raster.oam[sprite].y) & (sprite_height() - 1);
if(raster.oam[sprite].attr & 0x80) spritey ^= (sprite_height() - 1);
tileaddr += spritey + (spritey & 8);
raster.oam[sprite].tiledatalo = chr_load(tileaddr + 0);
tick();
tick();
raster.oam[sprite].tiledatahi = chr_load(tileaddr + 8);
tick();
tick();
if(raster_enable() && sprite == 6 && status.ly == 261) status.vaddr = status.taddr; //304
}
for(uint tile : range(2)) { //320-335
uint nametable = chr_load(0x2000 | (status.vaddr & 0x0fff));
uint tileaddr = status.bg_addr + (nametable << 4) + (scrolly() & 7);
tick();
tick();
uint attribute = chr_load(0x23c0 | (status.vaddr & 0x0fc0) | ((scrolly() >> 5) << 3) | (scrollx() >> 5));
if(scrolly() & 16) attribute >>= 4;
if(scrollx() & 16) attribute >>= 2;
tick();
scrollx_increment();
tick();
uint tiledatalo = chr_load(tileaddr + 0);
tick();
tick();
uint tiledatahi = chr_load(tileaddr + 8);
tick();
tick();
raster.nametable = (raster.nametable << 8) | nametable;
raster.attribute = (raster.attribute << 2) | (attribute & 3);
raster.tiledatalo = (raster.tiledatalo << 8) | tiledatalo;
raster.tiledatahi = (raster.tiledatahi << 8) | tiledatahi;
}
//336-339
chr_load(0x2000 | (status.vaddr & 0x0fff));
tick();
bool skip = (raster_enable() && status.field == 1 && status.ly == 261);
tick();
chr_load(0x2000 | (status.vaddr & 0x0fff));
tick();
tick();
//340
if(skip == false) tick();
return scanline();
}
}