Enum DecodeError 

#[non_exhaustive]
pub enum DecodeError {
    Truncated {
        at: usize,
    },
    UnsupportedPrefix {
        at: usize,
        byte: u8,
    },
    RepeatedPrefix {
        at: usize,
    },
    MisplacedRex {
        at: usize,
    },
    UnknownOpcode {
        at: usize,
        escaped: bool,
        opcode: u8,
    },
    InvalidOperandSize {
        at: usize,
    },
    UnknownExtension {
        at: usize,
        ext: u8,
    },
    RegisterOperand {
        at: usize,
    },
    UnusedRex {
        at: usize,
    },
}

Why bytes could not be decoded.

Every variant carries at, the offset in the input of the byte at fault. The decoder accepts exactly the encodings the form table describes, plus a redundant empty REX prefix (40) and a redundant REX.W on 64-bit-default forms; anything else is an error, never a guess.

Examples

use isa_lang::x86_64::{decode, DecodeError};

assert_eq!(decode(&[0x48, 0x83]), Err(DecodeError::Truncated { at: 2 }));
assert_eq!(decode(&[0xF0, 0x01, 0xC0]), Err(DecodeError::UnsupportedPrefix { at: 0, byte: 0xF0 }));
assert_eq!(decode(&[0x0F, 0x05]), Err(DecodeError::UnknownOpcode { at: 1, escaped: true, opcode: 0x05 }));
assert_eq!(
    decode(&[0x0F, 0x05]).unwrap_err().to_string(),
    "unknown opcode 0f 05 at byte 1",
);

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Truncated

The input ends before the instruction does.

Fields

at: usize

The offset at which another byte was needed.

UnsupportedPrefix

A legacy prefix outside the supported set (only 66 is supported: no LOCK, REP, segment, or address-size prefixes).

Fields

at: usize

Offset of the prefix.

byte: u8

The prefix byte.

RepeatedPrefix

The operand-size prefix 66 appears twice.

Fields

at: usize

Offset of the second 66.

MisplacedRex

A REX prefix is followed by another prefix instead of the opcode.

Fields

at: usize

Offset of the REX prefix.

UnknownOpcode

No form has this opcode.

Fields

at: usize

Offset of the opcode byte.

escaped: bool

Whether the opcode follows the 0F escape.

opcode: u8

The opcode byte.

InvalidOperandSize

The opcode exists, but not with this operand size (66 / REX.W).

Fields

at: usize

Offset of the opcode byte.

UnknownExtension

The opcode exists, but not with this ModRM reg extension.

Fields

at: usize

Offset of the ModRM byte.

ext: u8

The /digit found.

RegisterOperand

The form needs a memory operand but ModRM names a register.

Fields

at: usize

Offset of the ModRM byte.

UnusedRex

The REX prefix sets R, X, or B, but no operand of the form uses it.

Fields

at: usize

Offset of the REX prefix.

Implementations

impl DecodeError

pub const fn at(&self) -> usize

The offset in the input of the byte at fault.

Examples

use isa_lang::x86_64::decode;

assert_eq!(decode(&[0x66, 0x66, 0x90]).unwrap_err().at(), 1);

Trait Implementations

impl Clone for DecodeError

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for DecodeError

impl Debug for DecodeError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for DecodeError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for DecodeError

impl Error for DecodeError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl Hash for DecodeError

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for DecodeError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for DecodeError