Struct RexPrefix

pub struct RexPrefix { /* private fields */ }

Construct and emit the REX prefix byte.

For more details, see section 2.2.1, “REX Prefixes” in Intel’s reference manual.

Implementations

impl RexPrefix

pub const fn one_op(enc: u8, w_bit: bool, uses_8bit: bool) -> Self

Construct the RexPrefix for a unary instruction.

Used with a single register operand:

• x and r are unused.
• b extends the reg register, allowing access to r8-r15, or the top bit of the opcode digit.

pub const fn two_op( enc_reg: u8, enc_rm: u8, w_bit: bool, uses_8bit: bool, ) -> Self

Construct the RexPrefix for a binary instruction.

Used without a SIB byte or for register-to-register addressing:

• r extends the reg operand, allowing access to r8-r15.
• x is unused.
• b extends the r/m operand, allowing access to r8-r15.

pub const fn mem_op( enc_reg: u8, enc_rm: u8, w_bit: bool, uses_8bit: bool, ) -> Self

Construct the RexPrefix for a binary instruction where one operand is a memory address.

This is the same as RexPrefix::two_op except that enc_rm is guaranteed to address a 64-bit register. This has a slightly different meaning when uses_8bit is true to omit the REX prefix in more cases than two_op would emit.

pub const fn with_digit( digit: u8, enc_reg: u8, w_bit: bool, uses_8bit: bool, ) -> Self

Construct the RexPrefix for an instruction using an opcode digit.

:

• r extends the opcode digit.
• x is unused.
• b extends the reg operand, allowing access to r8-r15.

pub const fn three_op( enc_reg: u8, enc_index: u8, enc_base: u8, w_bit: bool, uses_8bit: bool, ) -> Self

Construct the RexPrefix for a ternary instruction, typically using a memory address.

Used with a SIB byte:

• r extends the reg operand, allowing access to r8-r15.
• x extends the index register, allowing access to r8-r15.
• b extends the base register, allowing access to r8-r15.

pub fn encode(&self, sink: &mut impl CodeSink)

Possibly emit the REX prefix byte.

This will only be emitted if the REX prefix is not 0x40 (the default) or if the instruction uses 8-bit operands.

Trait Implementations

impl Clone for RexPrefix

fn clone(&self) -> RexPrefix

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for RexPrefix