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Fixed: paging writes don't obstruct RAM.

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This commit is contained in:
Thomas Harte 2018-10-06 14:26:00 -04:00
parent 7830cda912
commit 76f3b9f6ba
1 changed files with 25 additions and 20 deletions
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45
Machines/MasterSystem/MasterSystem.cpp
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@ -168,7 +168,8 @@ class ConcreteMachine:
page_cartridge();
}
}
else if(write_pointers_[address >> 10]) write_pointers_[address >> 10][address & 1023] = *cycle.value;
if(write_pointers_[address >> 10]) write_pointers_[address >> 10][address & 1023] = *cycle.value;
break;
case CPU::Z80::PartialMachineCycle::Input:
@ -212,18 +213,8 @@ class ConcreteMachine:
case 0x00:
if(model_ == Analyser::Static::Sega::Target::Model::MasterSystem) {
// TODO: Obey the RAM enable.
// Either install the cartridge or don't.
if(!((*cycle.value) & 0x40)) {
page_cartridge();
} else {
map(read_pointers_, nullptr, 0xc000, 0x0000);
}
// Throw the BIOS on top if it isn't disabled.
if(!((*cycle.value) & 0x08)) {
map(read_pointers_, bios_, 8*1024, 0);
}
memory_control_ = *cycle.value;
page_cartridge();
}
break;
case 0x01:
@ -317,14 +308,28 @@ class ConcreteMachine:
}
uint8_t paging_registers_[3] = {0, 1, 2};
uint8_t memory_control_ = 0;
void page_cartridge() {
for(size_t c = 0; c < 3; ++c) {
const size_t start_addr = (paging_registers_[c] * 0x4000) % cartridge_.size();
map(
read_pointers_,
cartridge_.data() + start_addr,
std::min(static_cast<size_t>(0x4000), cartridge_.size() - start_addr),
c * 0x4000);
// Either install the cartridge or don't.
if(!(memory_control_ & 0x40)) {
for(size_t c = 0; c < 3; ++c) {
const size_t start_addr = (paging_registers_[c] * 0x4000) % cartridge_.size();
map(
read_pointers_,
cartridge_.data() + start_addr,
std::min(static_cast<size_t>(0x4000), cartridge_.size() - start_addr),
c * 0x4000);
}
// The first 1kb doesn't page though.
map(read_pointers_, cartridge_.data(), 0x400, 0x0000);
} else {
map(read_pointers_, nullptr, 0xc000, 0x0000);
}
// Throw the BIOS on top if it isn't disabled.
if(!(memory_control_ & 0x08)) {
map(read_pointers_, bios_, 8*1024, 0);
}
}
};