bsnes/sfc/chip/spc7110/dcu.cpp

58 lines
1.5 KiB
C++

#include "decompressor.cpp"
void SPC7110::dcu_load_address() {
unsigned table = r4801 | r4802 << 8 | r4803 << 16;
unsigned index = r4804 << 2;
unsigned addr = table + index;
dcu_mode = datarom_read(addr + 0);
dcu_addr = datarom_read(addr + 1) << 16;
dcu_addr |= datarom_read(addr + 2) << 8;
dcu_addr |= datarom_read(addr + 3) << 0;
}
void SPC7110::dcu_begin_transfer() {
if(dcu_mode == 3) return; //invalid mode
add_clocks(20);
decompressor->initialize(dcu_mode, dcu_addr);
decompressor->decode();
unsigned seek = r480b & 2 ? r4805 | r4806 << 8 : 0;
while(seek--) decompressor->decode();
r480c |= 0x80;
dcu_offset = 0;
}
uint8 SPC7110::dcu_read() {
if((r480c & 0x80) == 0) return 0x00;
if(dcu_offset == 0) {
for(unsigned row = 0; row < 8; row++) {
switch(decompressor->bpp) {
case 1:
dcu_tile[row] = decompressor->result;
break;
case 2:
dcu_tile[row * 2 + 0] = decompressor->result >> 0;
dcu_tile[row * 2 + 1] = decompressor->result >> 8;
break;
case 4:
dcu_tile[row * 2 + 0] = decompressor->result >> 0;
dcu_tile[row * 2 + 1] = decompressor->result >> 8;
dcu_tile[row * 2 + 16] = decompressor->result >> 16;
dcu_tile[row * 2 + 17] = decompressor->result >> 24;
break;
}
unsigned seek = r480b & 1 ? r4807 : 1;
while(seek--) decompressor->decode();
}
}
uint8 data = dcu_tile[dcu_offset++];
dcu_offset &= 8 * decompressor->bpp - 1;
return data;
}