holey-bytes/hbbytecode/src/lib.rs

#![no_std]

pub type OpR = u8;

pub type OpA = u64;
pub type OpO = u32;
pub type OpP = u16;

pub type OpB = u8;
pub type OpH = u16;
pub type OpW = u32;
pub type OpD = u64;

/// # Safety
/// Has to be valid to be decoded from bytecode.
pub unsafe trait BytecodeItem {}
macro_rules! define_items {
    ($($name:ident ($($item:ident),* $(,)?)),* $(,)?) => {
        $(
            #[repr(packed)]
            pub struct $name($(pub $item),*);
            unsafe impl BytecodeItem for $name {}
        )*
    };
}

define_items! {
    OpsRR   (OpR, OpR          ),
    OpsRRR  (OpR, OpR, OpR     ),
    OpsRRRR (OpR, OpR, OpR, OpR),
    OpsRRB  (OpR, OpR, OpB     ),
    OpsRRH  (OpR, OpR, OpH     ),
    OpsRRW  (OpR, OpR, OpW     ),
    OpsRD   (OpR, OpD          ),
    OpsRRD  (OpR, OpR, OpD     ),
    OpsRRAH (OpR, OpR, OpA, OpH),
    OpsRROH (OpR, OpR, OpO, OpH),
    OpsRRO  (OpR, OpR, OpO     ),
    OpsRRP  (OpR, OpR, OpP     ),
}

unsafe impl BytecodeItem for OpA {}
unsafe impl BytecodeItem for OpB {}
unsafe impl BytecodeItem for OpO {}
unsafe impl BytecodeItem for () {}

::with_builtin_macros::with_builtin! {
    let $spec = include_from_root!("instructions.in") in {
        /// Invoke macro with bytecode definition
        ///
        /// # Format
        /// ```text
        /// Opcode, Mnemonic, Type, Docstring;
        /// ```
        ///
        /// # Type
        /// ```text
        /// Types consist of letters meaning a single field
        /// | Type | Size (B) | Meaning                 |
        /// |:-----|:---------|:------------------------|
        /// | N    | 0        | Empty                   |
        /// | R    | 1        | Register                |
        /// | A    | 8        | Absolute address        |
        /// | O    | 4        | Relative address offset |
        /// | P    | 2        | Relative address offset |
        /// | B    | 1        | Immediate               |
        /// | H    | 2        | Immediate               |
        /// | W    | 4        | Immediate               |
        /// | D    | 8        | Immediate               |
        /// ```
        #[macro_export]
            macro_rules! invoke_with_def {
                ($macro:path) => {
                    $macro! { $spec }
                };
            }
    }
}

macro_rules! gen_opcodes {
    ($($opcode:expr, $mnemonic:ident, $_ty:ident, $doc:literal;)*) => {
        pub mod opcode {
            $(
                #[doc = $doc]
                pub const $mnemonic: u8 = $opcode;
            )*
        }
    };
}

invoke_with_def!(gen_opcodes);