cartridge

package
v0.7.2 Latest Latest
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 Go to latest Published: Nov 28, 2020 License: GPL-3.0, GPL-3.0 Imports: 14 Imported by: 0

Documentation

Overview

Package cartridge fully implements loading of mapping of cartridge memory. Cartridge memory is memory that is peripheral to the VCS and can grow quite complex.

There are many different types of mapping scheme supported by the package.

Some cartridge types contain additional RAM but the main difference is how they map additional ROM into the relatively small address space available for cartridges in the VCS. This is called bank-switching. All of these differences are handled transparently by the package.

Currently supported cartridge types are listed below. The strings in quotation marks are the identifiers that should be used to specify a particular mapping in the Mapping field of cartridgeloader.Loader. An empty string or "AUTO" tells the cartridge system to make a best guess. 

Atari 2k		"2k"
Atari 4k		"4k"
Atari 8k		"F8"
Atari 16k		"F6"
Atari 32k		"F4"
CBS case		"FA"
M-Network		"E7"
Parker Bros		"E0"
Tigervision		"3F"
DPC (Pitfall2)  "DPC"
DPC+			"DPC+"
3E+				"3E+"
Supercharger	"AR"

Index

Constants

View Source 
const (
	Ejected = "cartridge ejected"
)

Sentinal error returned if operation is on the ejected cartridge type.

Variables

This section is empty.

Functions

This section is empty.

Types

type Cartridge 

type Cartridge struct {
	bus.DebugBus
	bus.CPUBus

	Filename string
	Hash     string
	// contains filtered or unexported fields
}

Cartridge defines the information and operations for a VCS cartridge.

func NewCartridge 

func NewCartridge(prefs *preferences.Preferences) *Cartridge

NewCartridge is the preferred method of initialisation for the cartridge type.

func (*Cartridge) Attach 

func (cart *Cartridge) Attach(cartload cartridgeloader.Loader) error

Attach the cartridge loader to the VCS and make available the data to the CPU bus

How cartridges are mapped into the VCS's 4k space can differs dramatically. Much of the implementation details have been cribbed from Kevin Horton's "Cart Information" document [sizes.txt]. Other sources of information noted as appropriate.

func (*Cartridge) CopyBanks added in v0.7.1 

func (cart *Cartridge) CopyBanks() ([]mapper.BankContent, error)

CopyBanks returns the sequence of banks in a cartridge. To return the next bank in the sequence, call the function with the instance of mapper.BankContent returned from the previous call. The end of the sequence is indicated by the nil value. Start a new iteration with the nil argument.

func (*Cartridge) Eject 

func (cart *Cartridge) Eject()

Eject removes memory from cartridge space and unlike the real hardware, attaches a bank of empty memory - for convenience of the debugger.

func (*Cartridge) GetBank 

func (cart *Cartridge) GetBank(addr uint16) mapper.BankInfo

GetBank returns the current bank information for the specified address. See documentation for memorymap.Bank for more information.

func (*Cartridge) GetCartHotspots added in v0.7.1 

func (cart *Cartridge) GetCartHotspots() mapper.CartHotspotsBus

GetCartHotspots returns interface to hotspots bus or nil if cartridge has no hotspots it wants to report.

func (*Cartridge) GetContainer added in v0.7.1 

func (cart *Cartridge) GetContainer() mapper.CartContainer

GetContainer returns interface to cartridge container or nil if cartridge is not in a container.

func (*Cartridge) GetRAMbus added in v0.2.1 

func (cart *Cartridge) GetRAMbus() mapper.CartRAMbus

GetRAMbus returns interface to ram busor nil if catridge contains no RAM.

func (*Cartridge) GetRegistersBus added in v0.3.1 

func (cart *Cartridge) GetRegistersBus() mapper.CartRegistersBus

GetRegistersBus returns interface to the registers of the cartridge or nil if cartridge has no registers.

func (*Cartridge) GetStaticBus added in v0.3.1 

func (cart *Cartridge) GetStaticBus() mapper.CartStaticBus

GetStaticBus returns interface to the static area of the cartridge or nil if cartridge has no static area.

func (*Cartridge) GetTapeBus added in v0.7.1 

func (cart *Cartridge) GetTapeBus() mapper.CartTapeBus

GetTapeBus returns interface to a tape bus or nil if catridge has no tape.

func (*Cartridge) ID added in v0.2.1 

func (cart *Cartridge) ID() string

ID returns the cartridge mapping ID.

func (*Cartridge) IsEjected 

func (cart *Cartridge) IsEjected() bool

IsEjected returns true if no cartridge is attached.

func (*Cartridge) Listen 

func (cart *Cartridge) Listen(addr uint16, data uint8)

Listen for data at the specified address.

The VCS cartridge port is wired up to all 13 address lines of the 6507. Under normal operation, the chip-select line is used by the cartridge to know when to put data on the data bus. If it's not "on" then the cartridge does nothing.

However, the option is there to "listen" on the address bus. Notably the tigervision (3F) mapping listens for address 0x003f, which is in the TIA address space. When this address is triggered, the tigervision cartridge will use whatever is on the data bus to switch banks.

func (*Cartridge) MappingSummary added in v0.3.1 

func (cart *Cartridge) MappingSummary() string

MappingSummary returns a current string summary of the mapper.

func (*Cartridge) NumBanks 

func (cart *Cartridge) NumBanks() int

NumBanks returns the number of banks in the catridge.

func (*Cartridge) Patch 

func (cart *Cartridge) Patch(offset int, data uint8) error

Patch writes to cartridge memory. Offset is measured from the start of cartridge memory. It differs from Poke in that respect.

func (*Cartridge) Peek 

func (cart *Cartridge) Peek(addr uint16) (uint8, error)

Peek is an implementation of memory.DebugBus. Address must be normalised.

func (*Cartridge) Plumb added in v0.7.1 

func (cart *Cartridge) Plumb(s mapper.CartSnapshot)

func (*Cartridge) Poke 

func (cart *Cartridge) Poke(addr uint16, data uint8) error

Poke is an implementation of memory.DebugBus. Address must be normalised.

func (*Cartridge) Read 

func (cart *Cartridge) Read(addr uint16) (uint8, error)

Read is an implementation of memory.CPUBus. Address should not be normalised.

func (*Cartridge) Reset added in v0.7.1 

func (cart *Cartridge) Reset()

Reset volative contents of Cartridge.

func (*Cartridge) RewindBoundary added in v0.7.1 

func (cart *Cartridge) RewindBoundary() bool

RewindBoundary returns true if the cartridge indicates that something has happened that should not be part of the rewind history. Returns false if cartridge mapper does not care about the rewind sub-system.

func (*Cartridge) Snapshot added in v0.7.1 

func (cart *Cartridge) Snapshot() mapper.CartSnapshot

func (*Cartridge) Step added in v0.2.1 

func (cart *Cartridge) Step()

Step should be called every CPU cycle. The attached cartridge may or may not change its state as a result. In fact, very few cartridges care about this.

func (*Cartridge) String 

func (cart *Cartridge) String() string

func (*Cartridge) Write 

func (cart *Cartridge) Write(addr uint16, data uint8) error

Write is an implementation of memory.CPUBus. Address should not be normalised.

type DPCdataFetcher added in v0.2.1 

type DPCdataFetcher struct {
	Low    byte
	Hi     byte
	Top    byte
	Bottom byte

	// is the Low byte in the window between top and bottom
	Flag bool

	// music mode only used by data fetchers 4-7
	MusicMode bool
	OSCclock  bool
}

DPCdataFetcher represents a single DPC data fetcher.

type DPCregisters added in v0.2.1 

type DPCregisters struct {
	Fetcher [8]DPCdataFetcher

	// the current random number value
	RNG uint8
}

DPCregisters implements the mapper.CartRegisters interface.

func (DPCregisters) String added in v0.2.1 

func (r DPCregisters) String() string

Source Files

View all Source files

Directories

Path Synopsis
Package harmony implements the Harmony cartridge.
 Package harmony implements the Harmony cartridge.
Package mapper contains the CartMapper interface.
 Package mapper contains the CartMapper interface.
Package plusrom implements the PlusROM cartridge as developed by Wolfgang Stubig.
 Package plusrom implements the PlusROM cartridge as developed by Wolfgang Stubig.
Package supercharger implements the tape based cartridge format.
 Package supercharger implements the tape based cartridge format.

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