cartridge

package
v0.3.4 Latest Latest
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 Go to latest Published: Aug 4, 2020 License: GPL-3.0, GPL-3.0 Imports: 10 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

This section is empty.

Variables

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Functions

This section is empty.

Types

type Cartridge 

type Cartridge struct {
	bus.DebugBus
	bus.CPUBus
	Filename string
	Hash     string

	// when cartridge is in passive mode, cartridge hotspots do not work. We
	// send the passive value to the Read() and Write() functions of the mapper
	// and we also use it to prevent the Listen() function from triggering.
	// Useful for disassembly when we don't want the cartridge to react.
	Passive bool
	// contains filtered or unexported fields
}

Cartridge defines the information and operations for a VCS cartridge

func NewCartridge 

func NewCartridge() *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) 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) banks.Details

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

func (Cartridge) GetRAMbus added in v0.2.1 

func (cart Cartridge) GetRAMbus() bus.CartRAMbus

GetRAMbus returns an array of bus.CartRAM or nil if catridge contains no RAM

func (Cartridge) GetRegistersBus added in v0.3.1 

func (cart Cartridge) GetRegistersBus() bus.CartRegistersBus

GetRegistersBus returns interface to the debugging bus to the cartridge.

func (Cartridge) GetStaticBus added in v0.3.1 

func (cart Cartridge) GetStaticBus() bus.CartStaticBus

GetStaticBus returns interface to the debugging bus to the cartridge.

func (Cartridge) ID added in v0.2.1 

func (cart Cartridge) ID() string

ID returns the cartridge mapping ID

func (*Cartridge) Initialise 

func (cart *Cartridge) Initialise()

Initialise the cartridge

func (*Cartridge) IsEjected 

func (cart *Cartridge) IsEjected() bool

IsEjected returns true if no cartridge is attached

func (Cartridge) IterateBanks added in v0.3.1 

func (cart Cartridge) IterateBanks(prev *banks.Content) (*banks.Content, error)

IterateBanks returns the sequence of banks in a cartridge. To return the next bank in the sequence, call the function with the instance of banks.Content 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) 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) 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) 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 bus.CartRegisters interface

func (DPCregisters) String added in v0.2.1 

func (r DPCregisters) String() string

type DPCstatic added in v0.2.1 

type DPCstatic struct {
	Gfx []byte
}

DPCstatic implements the bus.CartStatic interface

Source Files

View all Source files

Directories

Path Synopsis
Package banks contains types that are used by the cartridge package to communicate information about catridge banks to the debugger.
 Package banks contains types that are used by the cartridge package to communicate information about catridge banks to the debugger.
Package harmony implements the Harmony cartridge.
 Package harmony implements the Harmony cartridge.
Package supercharger implements the tape based cartridge format.
 Package supercharger implements the tape based cartridge format.

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