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Refactor the MBC implementation to allow a single point of definition.

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Signed-off-by: Adrian.Conlon <adrian.conlon@gmail.com>
This commit is contained in:
Adrian.Conlon 2017-08-24 10:28:31 +01:00
parent da96454185
commit 448ee2f09f
5 changed files with 24 additions and 26 deletions
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4
LR35902/inc/Bus.h
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@ -182,7 +182,7 @@ namespace EightBit {
void loadBootRom(const std::string& path);
void loadGameRom(const std::string& path);
virtual uint8_t peek(uint16_t address) const;
virtual uint8_t peek(uint16_t address);
virtual void poke(uint16_t address, uint8_t value);
virtual uint8_t& reference();
@ -213,5 +213,7 @@ namespace EightBit {
void checkTimer(int cycles);
void validateCartridgeType();
uint8_t& reference(uint16_t address, bool& rom);
};
}

36
LR35902/src/Bus.cpp
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@ -40,18 +40,8 @@ void EightBit::Bus::loadGameRom(const std::string& path) {
validateCartridgeType();
}
uint8_t& EightBit::Bus::reference() {
auto effective = effectiveAddress(ADDRESS().word);
if ((effective < 0x100) && bootRomEnabled())
return placeDATA(m_bootRom[effective]);
if ((effective < 0x4000) && gameRomEnabled())
return placeDATA(m_gameRom[effective]);
if ((effective < 0x8000) && gameRomEnabled())
return placeDATA(m_gameRom[effective + (m_romBank * 0x4000)]);
return Memory::reference();
}
uint8_t EightBit::Bus::peek(uint16_t address) const {
uint8_t& EightBit::Bus::reference(uint16_t address, bool& rom) {
rom = true;
auto effective = effectiveAddress(address);
if ((effective < 0x100) && bootRomEnabled())
return m_bootRom[effective];
@ -59,18 +49,24 @@ uint8_t EightBit::Bus::peek(uint16_t address) const {
return m_gameRom[effective];
if ((effective < 0x8000) && gameRomEnabled())
return m_gameRom[effective + (m_romBank * 0x4000)];
rom = false;
return m_bus[effective];
}
uint8_t& EightBit::Bus::reference() {
bool rom;
auto& value = reference(ADDRESS().word, rom);
return rom ? placeDATA(value) : referenceDATA(value);
}
uint8_t EightBit::Bus::peek(uint16_t address) {
bool rom;
return reference(address, rom);
}
void EightBit::Bus::poke(uint16_t address, uint8_t value) {
auto effective = effectiveAddress(address);
if ((effective < 0x100) && bootRomEnabled())
m_bootRom[effective] = value;
if ((effective < 0x4000) && gameRomEnabled())
m_gameRom[effective] = value;
if ((effective < 0x8000) && gameRomEnabled())
m_gameRom[effective + (m_romBank * 0x4000)] = value;
m_bus[effective] = value;
bool rom;
reference(address, rom) = value;
}
void EightBit::Bus::Bus_WrittenByte(const AddressEventArgs& e) {

4
inc/Memory.h
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@ -53,10 +53,10 @@ namespace EightBit {
return DATA();
}
virtual uint8_t peek(uint16_t address) const;
virtual uint8_t peek(uint16_t address);
virtual void poke(uint16_t address, uint8_t value);
virtual uint16_t peekWord(uint16_t address) const;
virtual uint16_t peekWord(uint16_t address);
virtual int effectiveAddress(int address) const {
return address & m_addressMask;

2
inc/Processor.h
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@ -44,7 +44,7 @@ namespace EightBit {
static int promoteNibble(int value) { return value << 4; }
static int demoteNibble(int value) { return highNibble(value); }
const Memory& getMemory() const { return m_memory; }
Memory& getMemory() { return m_memory; }
register16_t& PC() { return pc; }

4
src/Memory.cpp
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@ -19,7 +19,7 @@ EightBit::Memory::Memory(uint16_t addressMask)
EightBit::Memory::~Memory() {
}
uint8_t EightBit::Memory::peek(uint16_t address) const {
uint8_t EightBit::Memory::peek(uint16_t address) {
return m_bus[address];
}
@ -27,7 +27,7 @@ void EightBit::Memory::poke(uint16_t address, uint8_t value) {
m_bus[address] = value;
}
uint16_t EightBit::Memory::peekWord(uint16_t address) const {
uint16_t EightBit::Memory::peekWord(uint16_t address) {
register16_t returned;
returned.low = peek(address);
returned.high = peek(address + 1);