Struct cranelift_codegen_shared::isa::x86::EncodingBits

pub struct EncodingBits(_);

Named interface to the u16 Encoding bits, representing an opcode.

Cranelift requires each recipe to have a single encoding size in bytes. X86 opcodes are variable length, so we use separate recipes for different styles of opcodes and prefixes. The opcode format is indicated by the recipe name prefix.

VEX/XOP and EVEX prefixes are not yet supported. Encodings using any of these prefixes are represented by separate recipes.

The encoding bits are:

0-7: The opcode byte . 8-9: pp, mandatory prefix: 00: none (Op*) 01: 66 (Mp*) 10: F3 (Mp*) 11: F2 (Mp*) 10-11: mm, opcode map: 00: (Op1/Mp1) 01: 0F (Op2/Mp2) 10: 0F 38 (Op3/Mp3) 11: 0F 3A (Op3/Mp3) 12-14 rrr, opcode bits for the ModR/M byte for certain opcodes. 15: REX.W bit (or VEX.W/E)

Methods

impl EncodingBits

pub fn new(op_bytes: &[u8], rrr: u16, rex_w: u16) -> Self

Constructs a new EncodingBits from parts.

pub fn with_rrr(self, rrr: u8) -> Self

Returns a copy of the EncodingBits with the RRR bits set.

pub fn with_rex_w(self) -> Self

Returns a copy of the EncodingBits with the REX.W bit set.

pub fn bits(self) -> u16

Returns the raw bits.

pub fn opcode_byte(self) -> u8

Instruction opcode byte, without the prefix.

pub fn prefix(self) -> OpcodePrefix

Prefix kind for the instruction, as an enum.

pub fn pp(self) -> u8

Extracts the PP bits of the OpcodePrefix.

pub fn mm(self) -> u8

Extracts the MM bits of the OpcodePrefix.

pub fn rrr(self) -> u8

Bits for the ModR/M byte for certain opcodes.

pub fn rex_w(self) -> u8

REX.W bit (or VEX.W/E).

Trait Implementations

impl Clone for EncodingBits

fn clone(&self) -> EncodingBits

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for EncodingBits

impl From<u16> for EncodingBits

fn from(bits: u16) -> Self

Performs the conversion.

impl PartialEq<EncodingBits> for EncodingBits

fn eq(&self, other: &EncodingBits) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &EncodingBits) -> bool

This method tests for !=.

impl StructuralPartialEq for EncodingBits