machine

package
v0.0.0-...-85084b6 Latest Latest
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 Go to latest Published: Mar 15, 2022 License: Apache-2.0 Imports: 11 Imported by: 0

Documentation

Index

Constants

View Source 
const (
	SdlDeviceId  = 0x0200
	SdlInit      = 1
	SdlPoll      = 2
	SdlPresent   = 3
	SdlClear     = 4
	SdlSetColor  = 5
	SdlDrawLine  = 6
	SdlDrawRect  = 7
	SdlFillRect  = 8
	SdlTicks     = 9
	SdlInitAudio = 0x0a
	SdlLoadWav   = 0x0b
	SdlPlayWav   = 0x0c
)
View Source 
const (
	ErrNoErr uint16 = iota
	ErrInvalidHandler
	ErrIOError
)
View Source 
const (
	PCAddr     = 0  // Program counter
	SPAddr     = 2  // Stack pointer, points to last byte written
	FPAddr     = 4  // Frame pointer
	IOReqAddr  = 6  // Address of I/O commands are written here to execute
	IOStatAddr = 8  // I/O status of last command, 0 = success, != 0 error
	RandAddr   = 10 // Writes are ignored, reads return random uint8/uint16
)
View Source 
const (
	StdoutDeviceId     = 0x0100
	StdoutCommandWrite = 1
)
View Source 
const BaseDirEnv = "MPU_BASE_DIR"

BaseDirEnv is the key for an environment variable to use for loading relative files.

Variables

This section is empty.

Functions

func DecodeOp 

func DecodeOp(in byte) (OpCode, AddressMode, AddressMode)

func EncodeOp 

func EncodeOp(op OpCode, m1, m2 AddressMode) byte

func LogIOError 

func LogIOError(format string, a ...interface{})

func RegisterSDLHandlers 

func RegisterSDLHandlers(m *IODispatcher)

Types

type AddressMode 

type AddressMode byte
const (
	Implied AddressMode = iota
	Absolute
	Immediate
	ImmediateByte
	OffsetByte
	Indirect
	Relative
	RelativeIndirect
)

func (AddressMode) String 

func (m AddressMode) String() string

type ByteSliceMemory 

type ByteSliceMemory struct {
	// contains filtered or unexported fields
}

ByteSliceMemory contains a set of (continuous) memory-mapped regions and a raw byte slice. The memory mapped area must be contiguous, and start at offset zero, and must consist of all word-sized memory.

func NewByteSliceMemory 

func NewByteSliceMemory(registers []Memory, raw []byte) *ByteSliceMemory

func (*ByteSliceMemory) BytesReaderAt 

func (m *ByteSliceMemory) BytesReaderAt(addr uint16) *bytes.Reader

func (*ByteSliceMemory) GetByte 

func (m *ByteSliceMemory) GetByte(addr uint16) byte

func (*ByteSliceMemory) GetWord 

func (m *ByteSliceMemory) GetWord(addr uint16) uint16

func (*ByteSliceMemory) PutByte 

func (m *ByteSliceMemory) PutByte(addr uint16, b byte)

func (*ByteSliceMemory) PutWord 

func (m *ByteSliceMemory) PutWord(addr uint16, w uint16)

func (*ByteSliceMemory) ReadZString 

func (m *ByteSliceMemory) ReadZString(addr uint16) string

type Encoding 

type Encoding struct {
	// contains filtered or unexported fields
}

Encoding defines the opcode and two address modes for each instruction. TODO It might be easier to both define and lookup at runtime by using bitfields want an int, rather than fields want a struct. If each operand mode is a flag then the combos can be too ... AbsAbs. Add | AbsAbs, Sub | AbsAbs, Mul | AbsAbs, ... may be worth a microbenchmark to see the runtime performance variations.

type Flags 

type Flags struct {
	PC       uint16
	SP       uint16
	FP       uint16
	Negative bool
	Zero     bool
	Carry    bool
	Bytes    bool
}

type IODispatcher 

type IODispatcher struct {
	// contains filtered or unexported fields
}

IODispatcher implements Memory, to map to an address, and provides another Memory object to view the status of the last IO request.

func NewDefaultDispatcher 

func NewDefaultDispatcher() *IODispatcher

func NewDispatcher 

func NewDispatcher() *IODispatcher

func (*IODispatcher) BytesReaderAt 

func (d *IODispatcher) BytesReaderAt(addr uint16) *bytes.Reader

func (*IODispatcher) GetByte 

func (d *IODispatcher) GetByte(addr uint16) byte

func (*IODispatcher) GetWord 

func (d *IODispatcher) GetWord(addr uint16) uint16

func (*IODispatcher) PutByte 

func (d *IODispatcher) PutByte(addr uint16, b byte)

func (*IODispatcher) PutWord 

func (d *IODispatcher) PutWord(addr uint16, w uint16)

func (*IODispatcher) ReadZString 

func (d *IODispatcher) ReadZString(addr uint16) string

func (*IODispatcher) RegisterIOHandler 

func (d *IODispatcher) RegisterIOHandler(id int, h IOHandler)

func (*IODispatcher) StatusRegister 

func (d *IODispatcher) StatusRegister() Memory

type IOHandler 

type IOHandler interface {
	Handle(m Memory, addr uint16) (errCode uint16)
}

IOHandler represents a single command handler within a device. Handlers must be registered via RegisterIOHandler. When invoked, machine will use encoding/binary to unmarshall the data pointed to into the handler and then call its Handle() method.

type Machine 

type Machine struct {
	// contains filtered or unexported fields
}

Machine implements MPU ... memory processing unit. It supports 27 instructions and 6 addressing modes.

func NewMachine 

func NewMachine(image []byte) *Machine

func NewMachineWithDevices 

func NewMachineWithDevices(d *IODispatcher, image []byte) *Machine

func (*Machine) Flags 

func (m *Machine) Flags() Flags

Flags returns a snapshot of the current state of the registers and flags.

func (*Machine) Memory 

func (m *Machine) Memory() Memory

func (*Machine) ReadInt8 

func (m *Machine) ReadInt8(addr uint16) int

ReadInt8 reads the given addr from memory as a byte and casts it to a signed int8 (as an int).

func (*Machine) Run 

func (m *Machine) Run()

func (*Machine) RunAt 

func (m *Machine) RunAt(pc uint16)

RunAt runs code from the given program counter until a HLT is encountered.

func (*Machine) Step 

func (m *Machine) Step(addr uint16) uint16

Step executes a single instruction at the given address, and returns the new PC address.

type Memory 

type Memory interface {
	PutByte(addr uint16, b byte)
	GetByte(addr uint16) byte
	PutWord(addr uint16, w uint16)
	GetWord(addr uint16) uint16
	ReadZString(addr uint16) string
	BytesReaderAt(addr uint16) *bytes.Reader
}

Memory defines the basic abstraction of reading/writing words and bytes to random access memory OR to memory-mapped registers.

type OpCode 

type OpCode byte
const (
	Hlt OpCode = iota
	Add
	Sub
	Mul
	Div
	And
	Or
	Xor
	Cpy
	Cmp
	Inc
	Dec
	Psh
	Pop
	Jsr
	Jmp
	Jeq
	Jne
	Jge
	Jlt
	Jcc
	Jcs
	Sav
	Seb
	Clb
	Clc
	Sec
	Ret
	Rst
)

func (OpCode) String 

func (o OpCode) String() string

type RNG 

type RNG struct {
	// contains filtered or unexported fields
}

RNG exposes a random number generator as a Memory unit. Writes are ignored. Both bytes and words can be read.

func NewRNG 

func NewRNG(seed int64) *RNG

func (*RNG) BytesReaderAt 

func (r *RNG) BytesReaderAt(addr uint16) *bytes.Reader

func (*RNG) GetByte 

func (r *RNG) GetByte(addr uint16) byte

func (*RNG) GetWord 

func (r *RNG) GetWord(addr uint16) uint16

func (*RNG) PutByte 

func (r *RNG) PutByte(addr uint16, b byte)

func (*RNG) PutWord 

func (r *RNG) PutWord(addr uint16, w uint16)

func (*RNG) ReadZString 

func (r *RNG) ReadZString(addr uint16) string

type Register 

type Register struct {
	// contains filtered or unexported fields
}

Register defines uint16 which is mapped to memory and therefore supports the put/get byte/word primitives.

func (Register) BytesReaderAt 

func (r Register) BytesReaderAt(addr uint16) *bytes.Reader

func (*Register) Get 

func (r *Register) Get() uint16

func (*Register) GetByte 

func (r *Register) GetByte(addr uint16) byte

func (*Register) GetWord 

func (r *Register) GetWord(addr uint16) uint16

func (*Register) PutByte 

func (r *Register) PutByte(addr uint16, b byte)

func (*Register) PutWord 

func (r *Register) PutWord(addr uint16, w uint16)

func (Register) ReadZString 

func (r Register) ReadZString(addr uint16) string

func (*Register) Set 

func (r *Register) Set(w uint16)

type SdlClearHandler 

type SdlClearHandler struct {
	Id uint16
}

func (*SdlClearHandler) Handle 

func (c *SdlClearHandler) Handle(m Memory, addr uint16) uint16

type SdlDrawLineHandler 

type SdlDrawLineHandler struct {
	Id             uint16
	X1, Y1, X2, Y2 uint16
}

func (SdlDrawLineHandler) Handle 

func (c SdlDrawLineHandler) Handle(m Memory, addr uint16) uint16

type SdlDrawRectHandler 

type SdlDrawRectHandler struct {
	Id         uint16
	X, Y, W, H uint16
}

func (*SdlDrawRectHandler) Handle 

func (c *SdlDrawRectHandler) Handle(m Memory, addr uint16) uint16

type SdlFillRectHandler 

type SdlFillRectHandler struct {
	Id         uint16
	X, Y, W, H uint16
}

func (SdlFillRectHandler) Handle 

func (c SdlFillRectHandler) Handle(m Memory, addr uint16) uint16

type SdlInitAudioHandler 

type SdlInitAudioHandler struct {
	Id uint16
}

func (*SdlInitAudioHandler) Handle 

func (s *SdlInitAudioHandler) Handle(m Memory, addr uint16) (errCode uint16)

type SdlInitHandler 

type SdlInitHandler struct {
	Id     uint16
	Width  uint16
	Height uint16
	Title  uint16 // Pointer to zstring
}

func (*SdlInitHandler) Handle 

func (c *SdlInitHandler) Handle(m Memory, addr uint16) uint16

type SdlLoadWavHandler 

type SdlLoadWavHandler struct {
	Id   uint16
	Path uint16
}

func (*SdlLoadWavHandler) Handle 

func (s *SdlLoadWavHandler) Handle(m Memory, addr uint16) (errCode uint16)

type SdlPlayWavHandler 

type SdlPlayWavHandler struct {
	Id   uint16
	Path uint16
}

func (*SdlPlayWavHandler) Handle 

func (s *SdlPlayWavHandler) Handle(m Memory, addr uint16) (errCode uint16)

type SdlPollHandler 

type SdlPollHandler struct {
	Id        uint16
	EventType uint16 // space for response
	Timestamp uint16 // space for response
}

func (*SdlPollHandler) Handle 

func (c *SdlPollHandler) Handle(m Memory, addr uint16) uint16

type SdlPresentHandler 

type SdlPresentHandler struct {
	Id      uint16
	DelayMS uint16
}

func (*SdlPresentHandler) Handle 

func (c *SdlPresentHandler) Handle(m Memory, addr uint16) uint16

type SdlSetColorHandler 

type SdlSetColorHandler struct {
	Id         uint16
	R, G, B, A uint8
}

func (SdlSetColorHandler) Handle 

func (c SdlSetColorHandler) Handle(m Memory, addr uint16) uint16

type SdlTicksHandler 

type SdlTicksHandler struct {
	Id    uint16
	Ticks uint16
}

func (*SdlTicksHandler) Handle 

func (s *SdlTicksHandler) Handle(m Memory, addr uint16) (errCode uint16)

type StdoutWriteHandler 

type StdoutWriteHandler struct {
	Id       uint16 // 0x0101
	PZString uint16 // pointer to zero-terminated string
}

func (*StdoutWriteHandler) Handle 

func (s *StdoutWriteHandler) Handle(m Memory, addr uint16) (errCode uint16)

Source Files

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