Documentation
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Index ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func Make ¶
Make creates our bytecode. First we find out how long the resulting instruction is going to be. That allows us to allocate a byte slice with the proper length. We then add the Opcode as its first byte by casting it into one. Then we iterate over the defined OperandWidths, take the matching element from operands, and put it in the instruction. After encoding the two byte operand in big endian, we increment offset by its width.
func ReadOperands ¶
func ReadOperands(def *Definition, ins Instructions) ([]int, int)
ReadOperands is Make's counterpart. It decodes the operands of a bytecode instruction.
func ReadUint16 ¶
func ReadUint16(ins Instructions) uint16
ReadUint16 turns a byte sequence (Instructions) into a uint16
func ReadUint8 ¶
func ReadUint8(ins Instructions) uint8
ReadUint8 turns a byte sequence (Instructions) into a uint16
Types ¶
type Definition ¶
Definition for an opcode. Name helps to make an Opcode readable and OperandWidths contains the number of bytes each operand takes up.
func Lookup ¶
func Lookup(op byte) (*Definition, error)
Lookup finds a definition by opcode. It returns it if it is found otherwise returns an error
type Instructions ¶
type Instructions []byte
Instructions - Type alias for a slice of byte.
func (Instructions) String ¶
func (ins Instructions) String() string
String is a sort of mini dissassembler to print our bytecode in human readable format
type Opcode ¶
type Opcode byte
Opcode is a type alias for byte
const ( // Constants OpConstant Opcode = iota // Aritmatic & stack pop OpAdd OpPop OpSub OpMul OpDiv OpMod // Boolean OpTrue OpFalse // Comparison/Logical OpEqualEqual OpNotEqual OpGreater OpGreaterEqual OpAnd OpOr // Prefix/unary OpMinus OpBang // Postfix/unary OpPlusPlus OpMinusMinus // Jump for conditionals OpJumpNotTruthy // Jump to alternative if consequence is not truthy OpJump // Jump no matter what (if we evaluate consequence and dont want the alternative) // Null OpNull // Get and Set global variables OpGetGlobal OpSetGlobal // Data structures and index access OpArray OpHash OpIndex // Call expression, return with value, return without value OpCall OpReturnValue // Tells VM to leave value on top of stack OpReturn // Tells VM implicit return of Null // Get and Set local bindings OpGetLocal OpSetLocal // Builtin functions OpGetBuiltin // Closures and it's variables OpClosure OpGetFree OpCurrentClosure )
Define our opcode types
Source Files