#![no_std]

macro_rules! constmod {
    ($vis:vis $mname:ident($repr:ty) { $($cname:ident = $val:expr),* $(,)? }) => {
        $vis mod $mname {
            $(pub const $cname: $repr = $val;)*
        }
    };
}

constmod!(pub opcode(u8) {
    NOP = 0, // N; Do nothing
    ADD = 1, // RRR; #0 ← #1 + #2
    SUB = 2, // RRR; #0 ← #1 - #2
    MUL = 3, // RRR; #0 ← #1 × #2
    DIV = 4, // RRR; #0 ← #1 ÷ #2
    REM = 5, // RRR; #0 ← #1 % #2
    AND = 6, // RRR; #0 ← #1 & #2
    OR  = 7, // RRR; #0 ← #1 | #2
    XOR = 8, // RRR; #0 ← #1 ^ #2
    NOT = 9, // RR;  #0 ← !#1

    // TODO: Add instruction for integer and float
    // reg ← reg + imm instructions

    ADDF = 10, // RRR; #0 ← #1 +. #2
    SUBF = 11, // RRR; #0 ← #1 +. #2
    MULF = 12, // RRR; #0 ← #1 +. #2
    DIVF = 13, // RRR; #0 ← #1 +. #2

    CP = 14, // RR;  Copy #0 ← #1
    LI = 15, // RI;  Load immediate, #0 ← imm #1
    LB = 16, // RRI; Load byte (8 bits), #0 ← [#1 + imm #2]
    LD = 17, // RRI; Load doublet (16 bits)
    LQ = 18, // RRI; Load quadlet (32 bits)
    LO = 19, // RRI; Load octlet (64 bits)
    SB = 20, // RRI; Store byte, [#1 + imm #2] ← #0
    SD = 21, // RRI; Store doublet
    SQ = 22, // RRI; Store quadlet
    SO = 23, // RRI; Store octlet

    PAGEMAP   = 24, // ?; Map a page
    PAGEUNMAP = 25, // ?; Unmap a page
    PAGEMP    = 26, // ?; Page modify protection flags

    JMP     = 27, // I; Unconditional jump
    JMPCOND = 28, // ?; Conditional jump
    RET     = 29, // N; Return
    ECALL   = 30, // N; Issue system call
});

#[repr(packed)] pub struct ParamRRR(pub u8, pub u8, pub u8);
#[repr(packed)] pub struct ParamRRI(pub u8, pub u8, pub u64);
#[repr(packed)] pub struct ParamRR(pub u8, pub u8);
#[repr(packed)] pub struct ParamRI(pub u8, pub u64);

/// # Safety
/// TODO.
pub unsafe trait OpParam {}
unsafe impl OpParam for ParamRRR {}
unsafe impl OpParam for ParamRRI {}
unsafe impl OpParam for ParamRR {}
unsafe impl OpParam for ParamRI {}
unsafe impl OpParam for u64 {}
unsafe impl OpParam for () {}