bsnes-classic/bsnes/snes/chip/sa1/bus/bus.cpp
2015-05-19 22:20:24 -04:00

224 lines
6.9 KiB
C++

#ifdef SA1_CPP
VBRBus vbrbus;
SA1Bus sa1bus;
namespace memory {
StaticRAM iram(2048);
UnmappedSA1 sa1_unmapped;
//accessed by:
VSPROM vsprom; //S-CPU + SA-1
CPUIRAM cpuiram; //S-CPU
SA1IRAM sa1iram; //SA-1
SA1BWRAM sa1bwram; //SA-1
CC1BWRAM cc1bwram; //S-CPU
BitmapRAM bitmapram; //SA-1
}
//$230c (VDPL), $230d (VDPH) use this bus to read variable-length data.
//this is used both to avoid VBR-reads from accessing MMIO registers, and
//to avoid syncing the S-CPU and SA-1*; as both chips are able to access
//these ports.
//(* eg, memory::cartram is used directly, as memory::sa1bwram syncs to the S-CPU)
void VBRBus::init() {
map(MapMode::Direct, 0x00, 0xff, 0x0000, 0xffff, memory::sa1_unmapped);
map(MapMode::Linear, 0x00, 0x3f, 0x0000, 0x07ff, memory::iram);
map(MapMode::Linear, 0x00, 0x3f, 0x3000, 0x37ff, memory::iram);
map(MapMode::Linear, 0x00, 0x3f, 0x6000, 0x7fff, memory::cartram);
map(MapMode::Linear, 0x00, 0x3f, 0x8000, 0xffff, memory::vsprom);
map(MapMode::Linear, 0x40, 0x4f, 0x0000, 0xffff, memory::cartram);
map(MapMode::Linear, 0x80, 0xbf, 0x0000, 0x07ff, memory::iram);
map(MapMode::Linear, 0x80, 0xbf, 0x3000, 0x37ff, memory::iram);
map(MapMode::Linear, 0x80, 0xbf, 0x6000, 0x7fff, memory::cartram);
map(MapMode::Linear, 0x80, 0xbf, 0x8000, 0xffff, memory::vsprom);
map(MapMode::Linear, 0xc0, 0xff, 0x0000, 0xffff, memory::vsprom);
}
void SA1Bus::init() {
map(MapMode::Direct, 0x00, 0xff, 0x0000, 0xffff, memory::sa1_unmapped);
map(MapMode::Linear, 0x00, 0x3f, 0x0000, 0x07ff, memory::sa1iram);
map(MapMode::Shadow, 0x00, 0x3f, 0x2200, 0x23ff, memory::mmio);
map(MapMode::Linear, 0x00, 0x3f, 0x3000, 0x37ff, memory::sa1iram);
map(MapMode::Linear, 0x00, 0x3f, 0x6000, 0x7fff, memory::sa1bwram);
map(MapMode::Linear, 0x00, 0x3f, 0x8000, 0xffff, memory::vsprom);
map(MapMode::Linear, 0x40, 0x4f, 0x0000, 0xffff, memory::sa1bwram);
map(MapMode::Linear, 0x60, 0x6f, 0x0000, 0xffff, memory::bitmapram);
map(MapMode::Linear, 0x80, 0xbf, 0x0000, 0x07ff, memory::sa1iram);
map(MapMode::Shadow, 0x80, 0xbf, 0x2200, 0x23ff, memory::mmio);
map(MapMode::Linear, 0x80, 0xbf, 0x3000, 0x37ff, memory::sa1iram);
map(MapMode::Linear, 0x80, 0xbf, 0x6000, 0x7fff, memory::sa1bwram);
map(MapMode::Linear, 0x80, 0xbf, 0x8000, 0xffff, memory::vsprom);
map(MapMode::Linear, 0xc0, 0xff, 0x0000, 0xffff, memory::vsprom);
}
unsigned UnmappedSA1::size() const { return 16 * 1024 * 1024; }
uint8 UnmappedSA1::read(unsigned) { return sa1.regs.mdr; }
void UnmappedSA1::write(unsigned, uint8) {}
//======
//VSPROM
//======
//this class maps $00:[ff00-ffff] for the purpose of supporting:
//$2209.d6 IVSW (S-CPU IRQ vector selection) (0 = cart, 1 = SA-1)
//$2209.d4 NVSW (S-CPU NMI vector selection) (0 = cart, 1 = SA-1)
//when set, vector addresses are over-ridden with SA-1 register settings:
//SIV = S-CPU IRQ vector address override
//SNV = S-CPU NMI vector address override
//
//$00:[ffea-ffeb|ffee-ffef] are special cased on read;
//all other addresses return original mapped data.
unsigned VSPROM::size() const {
return memory::cartrom.size();
}
uint8 VSPROM::read(unsigned addr) {
//use $7fex instead of $ffex due to linear mapping of 32k granularity ROM data
if((addr & 0xffffe0) == 0x007fe0) {
if(addr == 0x7fea && sa1.mmio.cpu_nvsw) return sa1.mmio.snv >> 0;
if(addr == 0x7feb && sa1.mmio.cpu_nvsw) return sa1.mmio.snv >> 8;
if(addr == 0x7fee && sa1.mmio.cpu_ivsw) return sa1.mmio.siv >> 0;
if(addr == 0x7fef && sa1.mmio.cpu_ivsw) return sa1.mmio.siv >> 8;
}
return memory::cartrom.read(addr);
}
void VSPROM::write(unsigned addr, uint8 data) {
memory::cartrom.write(addr, data);
}
//=======
//SA1IRAM
//=======
unsigned SA1IRAM::size() const {
return memory::iram.size();
}
uint8 SA1IRAM::read(unsigned addr) {
if(!debugger_access()) sa1.synchronize_cpu();
return memory::iram.read(addr);
}
void SA1IRAM::write(unsigned addr, uint8 data) {
if(!debugger_access()) sa1.synchronize_cpu();
memory::iram.write(addr, data);
}
//=======
//CPUIRAM
//=======
unsigned CPUIRAM::size() const {
return memory::iram.size();
}
uint8 CPUIRAM::read(unsigned addr) {
if(!debugger_access()) cpu.synchronize_coprocessor();
return memory::iram.read(addr);
}
void CPUIRAM::write(unsigned addr, uint8 data) {
if(!debugger_access()) cpu.synchronize_coprocessor();
memory::iram.write(addr, data);
}
//========
//SA1BWRAM
//========
unsigned SA1BWRAM::size() const {
return memory::cartram.size();
}
uint8 SA1BWRAM::read(unsigned addr) {
if(!debugger_access()) sa1.synchronize_cpu();
return memory::cartram.read(addr);
}
void SA1BWRAM::write(unsigned addr, uint8 data) {
if(!debugger_access()) sa1.synchronize_cpu();
memory::cartram.write(addr, data);
}
//========
//CC1BWRAM
//========
unsigned CC1BWRAM::size() const {
return memory::cartram.size();
}
uint8 CC1BWRAM::read(unsigned addr) {
if(!debugger_access()) cpu.synchronize_coprocessor();
if(dma) return sa1.dma_cc1_read(addr);
return memory::cartram.read(addr);
}
void CC1BWRAM::write(unsigned addr, uint8 data) {
if(!debugger_access()) cpu.synchronize_coprocessor();
memory::cartram.write(addr, data);
}
//=========
//BitmapRAM
//=========
unsigned BitmapRAM::size() const {
return 0x100000;
}
uint8 BitmapRAM::read(unsigned addr) {
if(!debugger_access()) sa1.synchronize_cpu();
if(sa1.mmio.bbf == 0) {
//4bpp
unsigned shift = addr & 1;
addr = (addr >> 1) & (memory::cartram.size() - 1);
switch(shift) { default:
case 0: return (memory::cartram.read(addr) >> 0) & 15;
case 1: return (memory::cartram.read(addr) >> 4) & 15;
}
} else {
//2bpp
unsigned shift = addr & 3;
addr = (addr >> 2) & (memory::cartram.size() - 1);
switch(shift) { default:
case 0: return (memory::cartram.read(addr) >> 0) & 3;
case 1: return (memory::cartram.read(addr) >> 2) & 3;
case 2: return (memory::cartram.read(addr) >> 4) & 3;
case 3: return (memory::cartram.read(addr) >> 6) & 3;
}
}
}
void BitmapRAM::write(unsigned addr, uint8 data) {
if(!debugger_access()) sa1.synchronize_cpu();
if(sa1.mmio.bbf == 0) {
//4bpp
unsigned shift = addr & 1;
addr = (addr >> 1) & (memory::cartram.size() - 1);
switch(shift) { default:
case 0: data = (memory::cartram.read(addr) & 0xf0) | ((data & 15) << 0); break;
case 1: data = (memory::cartram.read(addr) & 0x0f) | ((data & 15) << 4); break;
}
} else {
//2bpp
unsigned shift = addr & 3;
addr = (addr >> 2) & (memory::cartram.size() - 1);
switch(shift) { default:
case 0: data = (memory::cartram.read(addr) & 0xfc) | ((data & 3) << 0); break;
case 1: data = (memory::cartram.read(addr) & 0xf3) | ((data & 3) << 2); break;
case 2: data = (memory::cartram.read(addr) & 0xcf) | ((data & 3) << 4); break;
case 3: data = (memory::cartram.read(addr) & 0x3f) | ((data & 3) << 6); break;
}
}
memory::cartram.write(addr, data);
}
#endif