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Cleaning up

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This commit is contained in:
Anonymus Raccoon
2020-05-28 04:53:16 +02:00
parent 627fac8f2d
commit 29540ce9db
2 changed files with 38 additions and 33 deletions
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50
sources/CPU/DMA/DMA.cpp
View File

@@ -2,6 +2,7 @@
// Created by anonymus-raccoon on 5/26/20.
//
#include <iostream>
#include "DMA.hpp"
#include "../../Exceptions/InvalidAddress.hpp"
@@ -18,19 +19,19 @@ namespace ComSquare::CPU
{
switch (addr) {
case 0x0:
return this->controlRegister.raw;
return this->_controlRegister.raw;
case 0x1:
return this->port;
return this->_port;
case 0x2:
return this->aAddress.bytes[0];
return this->_aAddress.bytes[0];
case 0x3:
return this->aAddress.bytes[1];
return this->_aAddress.bytes[1];
case 0x4:
return this->aAddress.bytes[2];
return this->_aAddress.bytes[2];
case 0x5:
return this->count.bytes[0];
return this->_count.bytes[0];
case 0x6:
return this->count.bytes[1];
return this->_count.bytes[1];
default:
throw InvalidAddress("DMA read", addr);
}
@@ -40,25 +41,25 @@ namespace ComSquare::CPU
{
switch (addr) {
case 0x0:
this->controlRegister.raw = data;
this->_controlRegister.raw = data;
break;
case 0x1:
this->port = data;
this->_port = data;
break;
case 0x2:
this->aAddress.bytes[0] = data;
this->_aAddress.bytes[0] = data;
break;
case 0x3:
this->aAddress.bytes[1] = data;
this->_aAddress.bytes[1] = data;
break;
case 0x4:
this->aAddress.bytes[2] = data;
this->_aAddress.bytes[2] = data;
break;
case 0x5:
this->count.bytes[0] = data;
this->_count.bytes[0] = data;
break;
case 0x6:
this->count.bytes[1] = data;
this->_count.bytes[1] = data;
break;
default:
throw InvalidAddress("DMA read", addr);
@@ -68,16 +69,16 @@ namespace ComSquare::CPU
unsigned DMA::_writeOneByte(uint24_t aAddress, uint24_t bAddress)
{
// Address $2180 refers to the WRam data register. Write to/Read from this port when the a address is on the vram cause different behaviors.
if (this->port == 0x80) {
if (this->_port == 0x80) {
auto accessor = this->_bus->getAccessor(aAddress);
if (accessor && accessor->getComponent() == WRam) {
if (this->controlRegister.direction == AToB)
if (this->_controlRegister.direction == AToB)
return 8;
this->_bus->write(aAddress, 0xFF);
return 4;
}
}
if (this->controlRegister.direction == AToB) {
if (this->_controlRegister.direction == AToB) {
uint8_t data = this->_bus->read(aAddress);
this->_bus->write(bAddress, data);
} else {
@@ -91,21 +92,22 @@ namespace ComSquare::CPU
{
unsigned cycles = 8;
int i = 0;
std::cout << "Starting a DMA transfer" << std::endl;
do {
cycles += this->_writeOneByte(this->aAddress.raw, 0x2100 | this->port + this->getModeOffset(i));
if (!this->controlRegister.fixed)
this->aAddress.page += this->controlRegister.increment ? -1 : 1;
this->count.raw--;
cycles += this->_writeOneByte(this->_aAddress.raw, 0x2100 | (this->_port + this->_getModeOffset(i)));
if (!this->_controlRegister.fixed)
this->_aAddress.page += this->_controlRegister.increment ? -1 : 1;
this->_count.raw--;
i++;
} while (this->count.raw > 0 && cycles < maxCycles);
} while (this->_count.raw > 0);
this->enabled = false;
return cycles;
}
int DMA::getModeOffset(int index)
int DMA::_getModeOffset(int index)
{
switch (this->controlRegister.mode) {
switch (this->_controlRegister.mode) {
case OneToOne:
return 0;
case TwoToTwo:

21
sources/CPU/DMA/DMA.hpp
View File

@@ -34,12 +34,12 @@ namespace ComSquare::CPU
//! @brief Class handling all DMA/HDMA transfers (Direct Memory Access or H-Blank Direct Memory Access)
class DMA {
private:
//! @brief Write one byte using the A address, the port and the direction. Handle special cases where no write occurs.
//! @brief Write one byte using the A address, the port and the _direction. Handle special cases where no write occurs.
//! @return The number of cycles used.
unsigned _writeOneByte(uint24_t aAddress, uint24_t bAddress);
//! @brief Get an offset corresponding to the current DMAMode and the index of the currently transferred byte.
int getModeOffset(int index);
public:
int _getModeOffset(int index);
//! @brief DMA Control register (various information about the transfer)
union {
struct {
@@ -55,9 +55,9 @@ namespace ComSquare::CPU
Direction direction: 1;
};
uint8_t raw;
} controlRegister;
} _controlRegister;
//! @brief If this is 'xx', the register accessed will be $21xx.
uint8_t port;
uint8_t _port;
//! @brief The absolute long address of the data from the A bus.
union {
uint8_t bytes[3];
@@ -66,17 +66,20 @@ namespace ComSquare::CPU
uint8_t bank;
};
uint24_t raw: 24;
} aAddress;
} _aAddress;
//! @brief The number of bytes to be transferred.
union {
uint8_t bytes[2];
uint16_t raw;
} count;
//! @brief Is this channel set to run?
bool enabled;
} _count;
//! @brief The memory bus to use for read/write.
std::shared_ptr<Memory::MemoryBus> _bus;
public:
//! @brief Is this channel set to run?
bool enabled;
//! @brief Set the memory bus used by this dma channel.
void setBus(std::shared_ptr<Memory::MemoryBus> bus);