mirror of
https://github.com/bsnes-emu/bsnes.git
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79770f6207
Manually cherry-picked ares commit 70f361094b.
Co-Authored-By: absindx <59403574+absindx@users.noreply.github.com>
133 lines
4.1 KiB
C++
133 lines
4.1 KiB
C++
auto SA1::BWRAM::conflict() const -> bool {
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if(configuration.hacks.coprocessor.delayedSync) return false;
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if((cpu.r.mar & 0x40e000) == 0x006000) return true; //00-3f,80-bf:6000-7fff
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if((cpu.r.mar & 0xf00000) == 0x400000) return true; //40-4f:0000-ffff
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return false;
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}
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auto SA1::BWRAM::read(uint address, uint8 data) -> uint8 {
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if(!size()) return data;
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address = bus.mirror(address, size());
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return WritableMemory::read(address, data);
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}
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auto SA1::BWRAM::write(uint address, uint8 data) -> void {
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if(!size()) return;
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address = bus.mirror(address, size());
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return WritableMemory::write(address, data);
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}
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//note: addresses are translated prior to invoking this function:
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//00-3f,80-bf:6000-7fff size=0x2000 => 00:0000-1fff
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//40-4f:0000-ffff => untranslated
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auto SA1::BWRAM::readCPU(uint address, uint8 data) -> uint8 {
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cpu.synchronizeCoprocessors();
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if(address < 0x2000) { //$00-3f,80-bf:6000-7fff
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address = sa1.mmio.sbm * 0x2000 + (address & 0x1fff);
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}
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if(dma) return sa1.dmaCC1Read(address);
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return read(address, data);
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}
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auto SA1::BWRAM::writeCPU(uint address, uint8 data) -> void {
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cpu.synchronizeCoprocessors();
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if(address < 0x2000) { //$00-3f,80-bf:6000-7fff
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address = sa1.mmio.sbm * 0x2000 + (address & 0x1fff);
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}
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//note: BW-RAM protection works only when both SWEN and CWEN are disabled.
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if(!sa1.mmio.swen && !sa1.mmio.cwen && (address & 0x3ffff) < 0x100 << sa1.mmio.bwp) return;
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return write(address, data);
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}
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auto SA1::BWRAM::readSA1(uint address, uint8 data) -> uint8 {
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if(sa1.mmio.sw46 == 0) {
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//$40-43:0000-ffff x 32 projection
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address = (sa1.mmio.cbm & 0x1f) * 0x2000 + (address & 0x1fff);
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return readLinear(address, data);
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} else {
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//$60-6f:0000-ffff x 128 projection
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address = sa1.mmio.cbm * 0x2000 + (address & 0x1fff);
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return readBitmap(address, data);
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}
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}
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auto SA1::BWRAM::writeSA1(uint address, uint8 data) -> void {
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if(sa1.mmio.sw46 == 0) {
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//$40-43:0000-ffff x 32 projection
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address = (sa1.mmio.cbm & 0x1f) * 0x2000 + (address & 0x1fff);
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return writeLinear(address, data);
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} else {
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//$60-6f:0000-ffff x 128 projection
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address = sa1.mmio.cbm * 0x2000 + (address & 0x1fff);
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return writeBitmap(address, data);
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}
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}
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auto SA1::BWRAM::readLinear(uint address, uint8 data) -> uint8 {
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return read(address, data);
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}
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auto SA1::BWRAM::writeLinear(uint address, uint8 data) -> void {
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//note: BW-RAM protection works only when both SWEN and CWEN are disabled.
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//this is required for Kirby's Dream Land 3 to work:
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//* BWPA = 02 (protect 400000-4003ff)
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//* SWEN = 80 (writes enabled)
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//* CWEN = 00 (writes disabled)
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//KDL3 proceeds to write to 4001ax and 40032x which must succeed.
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//note: BWPA also affects SA-1 protection
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if(!sa1.mmio.swen && !sa1.mmio.cwen && (address & 0x3ffff) < 0x100 << sa1.mmio.bwp) return;
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return write(address, data);
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}
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auto SA1::BWRAM::readBitmap(uint20 address, uint8 data) -> uint8 {
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if(sa1.mmio.bbf == 0) {
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//4bpp
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uint shift = address & 1;
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address >>= 1;
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switch(shift) {
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case 0: return read(address) >> 0 & 15;
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case 1: return read(address) >> 4 & 15;
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}
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} else {
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//2bpp
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uint shift = address & 3;
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address >>= 2;
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switch(shift) {
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case 0: return read(address) >> 0 & 3;
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case 1: return read(address) >> 2 & 3;
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case 2: return read(address) >> 4 & 3;
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case 3: return read(address) >> 6 & 3;
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}
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}
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unreachable;
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}
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auto SA1::BWRAM::writeBitmap(uint20 address, uint8 data) -> void {
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if(sa1.mmio.bbf == 0) {
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//4bpp
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uint shift = address & 1;
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address >>= 1;
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switch(shift) {
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case 0: data = read(address) & 0xf0 | (data & 0x0f) << 0; break;
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case 1: data = read(address) & 0x0f | (data & 0x0f) << 4; break;
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}
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} else {
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//2bpp
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uint shift = address & 3;
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address >>= 2;
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switch(shift) {
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case 0: data = read(address) & 0xfc | (data & 0x03) << 0; break;
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case 1: data = read(address) & 0xf3 | (data & 0x03) << 2; break;
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case 2: data = read(address) & 0xcf | (data & 0x03) << 4; break;
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case 3: data = read(address) & 0x3f | (data & 0x03) << 6; break;
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}
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}
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write(address, data);
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}
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