bsnes/sfc/chip/superfx/timing/timing.cpp

98 lines
1.9 KiB
C++

#ifdef SUPERFX_CPP
void SuperFX::step(unsigned clocks) {
if(regs.romcl) {
regs.romcl -= min(clocks, regs.romcl);
if(regs.romcl == 0) {
regs.sfr.r = 0;
regs.romdr = bus_read((regs.rombr << 16) + regs.r[14]);
}
}
if(regs.ramcl) {
regs.ramcl -= min(clocks, regs.ramcl);
if(regs.ramcl == 0) {
bus_write(0x700000 + (regs.rambr << 16) + regs.ramar, regs.ramdr);
}
}
Coprocessor::step(clocks);
synchronize_cpu();
}
void SuperFX::rombuffer_sync() {
if(regs.romcl) step(regs.romcl);
}
void SuperFX::rombuffer_update() {
regs.sfr.r = 1;
regs.romcl = memory_access_speed;
}
uint8 SuperFX::rombuffer_read() {
rombuffer_sync();
return regs.romdr;
}
void SuperFX::rambuffer_sync() {
if(regs.ramcl) step(regs.ramcl);
}
uint8 SuperFX::rambuffer_read(uint16 addr) {
rambuffer_sync();
return bus_read(0x700000 + (regs.rambr << 16) + addr);
}
void SuperFX::rambuffer_write(uint16 addr, uint8 data) {
rambuffer_sync();
regs.ramcl = memory_access_speed;
regs.ramar = addr;
regs.ramdr = data;
}
void SuperFX::r14_modify(uint16 data) {
regs.r[14].data = data;
rombuffer_update();
}
void SuperFX::r15_modify(uint16 data) {
regs.r[15].data = data;
r15_modified = true;
}
void SuperFX::update_speed() {
//force SuperFX1 mode?
if(clockmode == 1) {
cache_access_speed = 2;
memory_access_speed = 6;
return;
}
//force SuperFX2 mode?
if(clockmode == 2) {
cache_access_speed = 1;
memory_access_speed = 5;
regs.cfgr.ms0 = 0; //cannot use high-speed multiplication in 21MHz mode
return;
}
//default: allow S-CPU to select mode
cache_access_speed = (regs.clsr ? 1 : 2);
memory_access_speed = (regs.clsr ? 5 : 6);
if(regs.clsr) regs.cfgr.ms0 = 0; //cannot use high-speed multiplication in 21MHz mode
}
void SuperFX::timing_reset() {
update_speed();
r15_modified = false;
regs.romcl = 0;
regs.romdr = 0;
regs.ramcl = 0;
regs.ramar = 0;
regs.ramdr = 0;
}
#endif