Module ketos::bytecode

Implements encoding and decoding of bytecode instruction format.

Bytecode instructions consist of a one-byte operand, followed by zero or more unsigned integer operands in the range [0, 0x7fff] (15 bits).

Operands in the range [0, 0x7f] are encoded as a single byte. Operands in the range [0x80, 0x7fff] are encoded as two bytes: the first containing the higher 7 bits of the operand with the 8th bit set; the second containing the lower 8 bits of the operand.

Combination instructions exist to combine the operation of two or more instructions which commonly follow, e.g. ConstPush(n) operates as Const(n) followed by Push.

Shortcut opcodes exist for common instructions that accept operands, such as Const and Load. These opcodes replace a long-form instruction with a single opcode, e.g. the CONST_0 opcode replaces the two-byte sequence CONST, followed by operand 0.

Modules

code_flags	Bit flag values for Code::flags
opcodes	Opcode values of compiled bytecode.

Structs

Code	Represents a compiled bytecode function or expression.
CodeBlock	Contains a series of bytecode instructions
CodeReader	Reads Instruction values from a stream of bytes.

Enums

Instruction	Represents an instruction and any immediate parameters.
JumpInstruction	Partial representation of jump Instruction variants before label values have been determined.

Constants

BYTECODE_VERSION	Bytecode version number, indicating the version of the most recent breaking change to the bytecode format. The version represents a ketos version number, e.g. 0x01_02_03_00 corresponds to version 1.2.3. (The least significant 8 bits don't mean anything yet.)
MAX_LONG_OPERAND	Maximum value of a long-encoded operand.
MAX_SHORT_OPERAND	Maximum value of a short-encoded operand.