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//! # `yaxpeax-x86`, a decoder for x86-family instruction sets
//!
//! `yaxpeax-x86` provides x86 decoders, for 64-, 32-, and 16-bit modes. `yaxpeax-x86` also
//! implements traits defined by `yaxpeax_arch`, making it suitable for interchangeable use with
//! other `yaxpeax`-family instruction decoders.
//!
//! ## usage
//!
//! the fastest way to decode an x86 instruction is through [`amd64::InstDecoder::decode_slice()`]:
//! ```
//! let decoder = yaxpeax_x86::amd64::InstDecoder::default();
//!
//! let inst = decoder.decode_slice(&[0x33, 0xc0]).unwrap();
//!
//! #[cfg(features="fmt")]
//! assert_eq!("xor eax, eax", inst.to_string());
//! ```
//!
//! instructions, operands, registers, and generally all decoding structures, are in their mode's
//! repsective submodule:
//! * `x86_64`/`amd64` decoding is under [`long_mode`]
//! * `x86_32`/`x86` decoding is under [`protected_mode`]
//! * `x86_16`/`8086` decoding is under [`real_mode`]
//!
//! all modes have equivalent data available in a decoded instruction. for example, all modes have
//! library-friendly `Operand` and `RegSpec` types:
//!
//! ```
//! use yaxpeax_x86::amd64::{InstDecoder, Operand, RegSpec};
//!
//! let decoder = yaxpeax_x86::amd64::InstDecoder::default();
//!
//! let inst = decoder.decode_slice(&[0x33, 0x01]).unwrap();
//!
//! #[cfg(features="fmt")]
//! assert_eq!("xor eax, dword [rcx]", inst.to_string());
//!
//! assert_eq!(Operand::Register(RegSpec::eax()), inst.operand(0));
//! #[cfg(features="fmt")]
//! assert_eq!("eax", inst.operand(0).to_string());
//! assert_eq!(Operand::RegDeref(RegSpec::rcx()), inst.operand(1));
//!
//! // an operand in isolation does not know the size of memory it references, if any
//! #[cfg(features="fmt")]
//! assert_eq!("[rcx]", inst.operand(1).to_string());
//!
//! // and for memory operands, the size must be read from the instruction itself:
//! let mem_size: yaxpeax_x86::amd64::MemoryAccessSize = inst.mem_size().unwrap();
//! assert_eq!("dword", mem_size.size_name());
//!
//! // `MemoryAccessSize::size_name()` is how its `Display` impl works, as well:
//! #[cfg(features="fmt")]
//! assert_eq!("dword", mem_size.to_string());
//! ```
//!
//! `yaxpeax-x86` can also be used to decode instructions generically through the `yaxpeax-arch`
//! traits:
//! ```
//! mod decoder {
//! use yaxpeax_arch::{Arch, AddressDisplay, Decoder, Reader, ReaderBuilder};
//!
//! // have to play some games so this example works right even without `fmt` enabled!
//! #[cfg(feature="fmt")]
//! trait InstBound: std::fmt::Display {}
//! #[cfg(not(feature="fmt"))]
//! trait InstBound {}
//!
//! #[cfg(feature="fmt")]
//! impl <T: std::fmt::Display> InstBound for T {}
//! #[cfg(not(feature="fmt"))]
//! impl <T> InstBound for T {}
//!
//! pub fn decode_stream<
//! 'data,
//! A: yaxpeax_arch::Arch,
//! U: ReaderBuilder<A::Address, A::Word>,
//! >(data: U) where
//! A::Instruction: InstBound,
//! {
//! let mut reader = ReaderBuilder::read_from(data);
//! let mut address: A::Address = reader.total_offset();
//!
//! let decoder = A::Decoder::default();
//! let mut decode_res = decoder.decode(&mut reader);
//! loop {
//! match decode_res {
//! Ok(ref inst) => {
//! #[cfg(feature="fmt")]
//! println!("{}: {}", address.show(), inst);
//! decode_res = decoder.decode(&mut reader);
//! address = reader.total_offset();
//! }
//! Err(e) => {
//! println!("{}: decode error: {}", address.show(), e);
//! break;
//! }
//! }
//! }
//! }
//! }
//!
//! use yaxpeax_x86::amd64::{Arch as x86_64};
//! use yaxpeax_arch::{ReaderBuilder, U8Reader};
//! let data: &[u8] = &[0x55, 0x33, 0xc0, 0x48, 0x8b, 0x02, 0x5d, 0xc3];
//! decoder::decode_stream::<x86_64, _>(data);
//! ```
//!
//! ## `#![no_std]`
//!
//! `yaxpeax-x86` supports `no_std` usage. to be built `no_std`, `yaxpeax-x86` only needs
//! `default-features = false` in the corresponding `Cargo.toml` dependency. if formatting is
//! needed with `std` disabled, it can be re-enabled by explicitly requesting the `fmt` features
//! like:
//! ```text
//! yaxpeax-x86 = { version = "*", default-features = false, features = ["fmt"] }
//! ```
//!
//! this is how the `.so` and `.a` packaging in
//! [`ffi/`](https://github.com/iximeow/yaxpeax-x86/tree/no-gods-no-/ffi) is performed.
#![no_std]
#[cfg(feature="use-serde")]
#[macro_use] extern crate serde_derive;
#[cfg(feature="use-serde")]
extern crate serde;
#[cfg(feature="std")]
extern crate alloc;
pub mod long_mode;
pub use long_mode as amd64;
pub use long_mode::Arch as x86_64;
pub mod protected_mode;
pub use protected_mode::Arch as x86_32;
pub mod real_mode;
pub use real_mode::Arch as x86_16;
mod safer_unchecked;
const MEM_SIZE_STRINGS: [&'static str; 64] = [
"byte", "word", "BUG", "dword", "ptr", "far", "BUG", "qword",
"BUG", "mword", "BUG", "BUG", "BUG", "BUG", "BUG", "xmmword",
"BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG",
"BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "ymmword",
"BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG",
"BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG",
"BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "BUG",
"BUG", "BUG", "BUG", "BUG", "BUG", "BUG", "ptr", "zmmword",
];
pub struct MemoryAccessSize {
size: u8,
}
impl MemoryAccessSize {
/// return the number of bytes referenced by this memory access.
///
/// if the number of bytes cannot be confidently known by the instruction in isolation (as is
/// the case for `xsave`/`xrstor`-style "operate on all processor state" instructions), this
/// function will return `None`.
pub fn bytes_size(&self) -> Option<u8> {
if self.size == 63 {
None
} else {
Some(self.size)
}
}
/// a human-friendly label for the number of bytes this memory access references.
///
/// there are some differences from size names that may be expected elsewhere; `yaxpeax-x86`
/// prefers to use consistent names for a width even if the way those bytes are used varies.
///
/// the sizes `yaxpeax-x86` knows are as follows:
/// | size (bytes) | name |
/// |--------------|------------|
/// | 1 | `byte` |
/// | 2 | `word` |
/// | 4 | `dword` |
/// | 6 | `far` |
/// | 8 | `qword` |
/// | 10 | `mword` |
/// | 16 | `xmmword` |
/// | 32 | `ymmword` |
/// | 64 | `zmmword` |
/// | variable | `ptr` |
///
/// "mword" refers to an mmx-sized access - 80 bits, or 10 bytes. `mword` is also used for
/// 64-bit far calls, because they reference a contiguous ten bytes; two bytes of segment
/// selector and eight bytes of address.
///
/// "variable" accesses access a number of bytes dependent on the physical processor and its
/// operating mode. this is particularly relevant for `xsave`/`xrstor`-style instructions.
pub fn size_name(&self) -> &'static str {
MEM_SIZE_STRINGS[self.size as usize - 1]
}
}
#[cfg(feature = "fmt")]
impl core::fmt::Display for MemoryAccessSize {
fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
f.write_str(self.size_name())
}
}
#[cfg(feature = "fmt")]
impl core::fmt::Debug for MemoryAccessSize {
fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
core::fmt::Display::fmt(self, f)
}
}
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