#![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
    SL   = 9,  // RRR; #0 ← #1 « #2
    SR   = 10, // RRR; #0 ← #1 » #2
    SRS  = 11, // RRR; #0 ← #1 » #2 (signed)
    CMP  = 12, // RRR; #0 ← #1 <=> #2
    CMPU = 13, // RRR; #0 ← #1 <=> #2 (unsigned)
    NOT  = 14, // RR;  #0 ← !#1

    ADDF  = 15, // RRR; #0 ← #1 +. #2
    SUBF  = 16, // RRR; #0 ← #1 +. #2
    MULF  = 17, // RRR; #0 ← #1 +. #2
    DIVF  = 18, // RRR; #0 ← #1 +. #2
    ADDI  = 19, // RRI; #0 ← #1 + imm #2
    MULI  = 20, // RRI; #0 ← #1 × imm #2
    REMI  = 21, // RRI; #0 ← #1 % imm #2
    ANDI  = 22, // RRI; #0 ← #1 & imm #2
    ORI   = 23, // RRI; #0 ← #1 | imm #2
    XORI  = 24, // RRI; #0 ← #1 ^ imm #2
    SLI   = 25, // RRI; #0 ← #1 « imm #2
    SRI   = 26, // RRI; #0 ← #1 » imm #2
    SRSI  = 27, // RRI; #0 ← #1 » imm #2 (signed)
    CMPI  = 28, // RRI; #0 ← #1 <=> imm #2
    CMPUI = 29, // RRI; #0 ← #1 <=> imm #2 (unsigned)

    ADDFI = 30, // RRI; #0 ← #1 +. imm #2
    MULFI = 31, // RRI; #0 ← #1 *. imm #2

    CP = 32, // RR;  Copy #0 ← #1
    LI = 33, // RI;  Load immediate, #0 ← imm #1
    LB = 34, // RRI; Load byte (8 bits), #0 ← [#1 + imm #2]
    LD = 35, // RRI; Load doublet (16 bits)
    LQ = 36, // RRI; Load quadlet (32 bits)
    LO = 37, // RRI; Load octlet (64 bits)
    SB = 38, // RRI; Store byte, [#1 + imm #2] ← #0
    SD = 39, // RRI; Store doublet
    SQ = 40, // RRI; Store quadlet
    SO = 41, // RRI; Store octlet

    JMP   = 42, // RI;  Unconditional jump [#0 + imm #1]
    JEQ   = 43, // RRI; if #0 = #1 → jump imm #2
    JNE   = 44, // RRI; if #0 ≠ #1 → jump imm #2
    JLT   = 45, // RRI; if #0 < #1 → jump imm #2
    JGT   = 46, // RRI; if #0 > #1 → jump imm #2
    JLTU  = 47, // RRI; if #0 < #1 → jump imm #2 (unsigned)
    JGTU  = 48, // RRI; if #0 > #1 → jump imm #2 (unsigned)
    RET   = 49, // N; Return
    ECALL = 50, // 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 () {}