mirror of https://github.com/bsnes-emu/bsnes.git
118 lines
3.5 KiB
C++
118 lines
3.5 KiB
C++
//direct data transfer
|
|
auto SA1::dmaNormal() -> void {
|
|
while(mmio.dtc--) {
|
|
uint8 data = r.mdr;
|
|
uint24 source = mmio.dsa++;
|
|
uint16 target = mmio.dda++;
|
|
|
|
if(mmio.sd == DMA::SourceROM && mmio.dd == DMA::DestBWRAM) {
|
|
step(bwram.conflict() ? 8 : 4);
|
|
data = rom.readSA1(source, data);
|
|
bwram.write(target, data);
|
|
}
|
|
|
|
if(mmio.sd == DMA::SourceROM && mmio.dd == DMA::DestIRAM) {
|
|
step(iram.conflict() ? 6 : 4);
|
|
data = rom.readSA1(source, data);
|
|
iram.write(target, data);
|
|
}
|
|
|
|
if(mmio.sd == DMA::SourceBWRAM && mmio.dd == DMA::DestIRAM) {
|
|
step(bwram.conflict() ? 8 : iram.conflict() ? 6 : 4);
|
|
data = bwram.read(source, data);
|
|
iram.write(target, data);
|
|
}
|
|
|
|
if(mmio.sd == DMA::SourceIRAM && mmio.dd == DMA::DestBWRAM) {
|
|
step(bwram.conflict() ? 8 : iram.conflict() ? 6 : 4);
|
|
data = iram.read(source, data);
|
|
bwram.write(target, data);
|
|
}
|
|
}
|
|
|
|
mmio.dma_irqfl = true;
|
|
if(mmio.dma_irqen) mmio.dma_irqcl = 0;
|
|
}
|
|
|
|
//type-1 character conversion
|
|
auto SA1::dmaCC1() -> void {
|
|
bwram.dma = true;
|
|
mmio.chdma_irqfl = true;
|
|
if(mmio.chdma_irqen) {
|
|
mmio.chdma_irqcl = 0;
|
|
cpu.r.irq = 1;
|
|
}
|
|
}
|
|
|
|
//((byte & 6) << 3) + (byte & 1) explanation:
|
|
//transforms a byte index (0-7) into a planar index:
|
|
//result[] = {0, 1, 16, 17, 32, 33, 48, 49};
|
|
//works for 2bpp, 4bpp and 8bpp modes
|
|
|
|
//type-1 character conversion
|
|
auto SA1::dmaCC1Read(uint addr) -> uint8 {
|
|
//16 bytes/char (2bpp); 32 bytes/char (4bpp); 64 bytes/char (8bpp)
|
|
uint charmask = (1 << (6 - mmio.dmacb)) - 1;
|
|
|
|
if((addr & charmask) == 0) {
|
|
//buffer next character to I-RAM
|
|
uint bpp = 2 << (2 - mmio.dmacb);
|
|
uint bpl = (8 << mmio.dmasize) >> mmio.dmacb;
|
|
uint bwmask = bwram.size() - 1;
|
|
uint tile = ((addr - mmio.dsa) & bwmask) >> (6 - mmio.dmacb);
|
|
uint ty = (tile >> mmio.dmasize);
|
|
uint tx = tile & ((1 << mmio.dmasize) - 1);
|
|
uint bwaddr = mmio.dsa + ty * 8 * bpl + tx * bpp;
|
|
|
|
for(auto y : range(8)) {
|
|
uint64 data = 0;
|
|
for(auto byte : range(bpp)) {
|
|
data |= (uint64)bwram.read((bwaddr + byte) & bwmask) << (byte << 3);
|
|
}
|
|
bwaddr += bpl;
|
|
|
|
uint8 out[] = {0, 0, 0, 0, 0, 0, 0, 0};
|
|
for(auto x : range(8)) {
|
|
out[0] |= (data & 1) << 7 - x; data >>= 1;
|
|
out[1] |= (data & 1) << 7 - x; data >>= 1;
|
|
if(mmio.dmacb == 2) continue;
|
|
out[2] |= (data & 1) << 7 - x; data >>= 1;
|
|
out[3] |= (data & 1) << 7 - x; data >>= 1;
|
|
if(mmio.dmacb == 1) continue;
|
|
out[4] |= (data & 1) << 7 - x; data >>= 1;
|
|
out[5] |= (data & 1) << 7 - x; data >>= 1;
|
|
out[6] |= (data & 1) << 7 - x; data >>= 1;
|
|
out[7] |= (data & 1) << 7 - x; data >>= 1;
|
|
}
|
|
|
|
for(auto byte : range(bpp)) {
|
|
uint p = mmio.dda + (y << 1) + ((byte & 6) << 3) + (byte & 1);
|
|
iram.write(p & 0x07ff, out[byte]);
|
|
}
|
|
}
|
|
}
|
|
|
|
return iram.read((mmio.dda + (addr & charmask)) & 0x07ff);
|
|
}
|
|
|
|
//type-2 character conversion
|
|
auto SA1::dmaCC2() -> void {
|
|
//select register file index (0-7 or 8-15)
|
|
const uint8* brf = &mmio.brf[(dma.line & 1) << 3];
|
|
uint bpp = 2 << (2 - mmio.dmacb);
|
|
uint addr = mmio.dda & 0x07ff;
|
|
addr &= ~((1 << (7 - mmio.dmacb)) - 1);
|
|
addr += (dma.line & 8) * bpp;
|
|
addr += (dma.line & 7) * 2;
|
|
|
|
for(auto byte : range(bpp)) {
|
|
uint8 output = 0;
|
|
for(auto bit : range(8)) {
|
|
output |= ((brf[bit] >> byte) & 1) << (7 - bit);
|
|
}
|
|
iram.write(addr + ((byte & 6) << 3) + (byte & 1), output);
|
|
}
|
|
|
|
dma.line = (dma.line + 1) & 15;
|
|
}
|