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Ensures Codemasters games have the proper initial state.

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This commit is contained in:
Thomas Harte 2018-10-19 22:10:14 -04:00
parent 6fff514901
commit f49718e94b
1 changed files with 25 additions and 6 deletions
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31
Machines/MasterSystem/MasterSystem.cpp
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@ -108,6 +108,13 @@ class ConcreteMachine:
cartridge_.resize(48*1024);
memset(&cartridge_[48*1024 - new_space], 0xff, new_space);
}
if(paging_scheme_ == Target::PagingScheme::Codemasters) {
// The Codemasters cartridges start with pages 0, 1 and 0 again initially visible.
paging_registers_[0] = 0;
paging_registers_[1] = 1;
paging_registers_[2] = 0;
}
page_cartridge();
// Load the BIOS if relevant.
@ -175,10 +182,20 @@ class ConcreteMachine:
break;
case CPU::Z80::PartialMachineCycle::Write:
if(address >= 0xfffd && cartridge_.size() > 48*1024) {
if(paging_registers_[address - 0xfffd] != *cycle.value) {
paging_registers_[address - 0xfffd] = *cycle.value;
page_cartridge();
if(paging_scheme_ == Target::PagingScheme::Sega) {
if(address >= 0xfffd && cartridge_.size() > 48*1024) {
if(paging_registers_[address - 0xfffd] != *cycle.value) {
paging_registers_[address - 0xfffd] = *cycle.value;
page_cartridge();
}
}
} else {
// i.e. this is the Codemasters paging scheme.
if(!(address&0x3fff) && address < 0xc000) {
if(paging_registers_[address >> 14] != *cycle.value) {
paging_registers_[address >> 14] = *cycle.value;
page_cartridge();
}
}
}
@ -370,8 +387,10 @@ class ConcreteMachine:
c * 0x4000);
}
// The first 1kb doesn't page though.
map(read_pointers_, cartridge_.data(), 0x400, 0x0000);
// The first 1kb doesn't page though, if this is the Sega paging scheme.
if(paging_scheme_ == Target::PagingScheme::Sega) {
map(read_pointers_, cartridge_.data(), 0x400, 0x0000);
}
} else {
map(read_pointers_, nullptr, 0xc000, 0x0000);
}