Inline assembly

asm blocks

asm is a low-level escape hatch for inserting target-architecture instructions.

fun read_value() -> i64 {
    var result: i64 = 0;
    asm {
        "mov rax, 123"
        out("rax") result
    }
    return result;
}

String literals in the block become assembly instruction entries.

Inputs and outputs

var result: i64 = 0;
asm {
    "mov rax, rdi"
    in("rdi") 123
    out("rax") result
}

• in("reg") expression associates a Wave value with an input operand.
• out("reg") target stores an output into an assignable Wave target.
• Register names can be parsed from strings or identifier forms.

An input operand can be a variable, an integer or string literal, &identifier, deref identifier, or a negative numeric literal.

clobbers

If a block changes registers or memory state beyond explicit outputs, list that state in clobber(...).

asm {
    "nop"
    clobber("rax", "rcx", "memory")
}

What to verify

• Instruction syntax must match the target architecture and LLVM inline-assembly contract.
• Do not destroy registers that the calling convention requires you to preserve.
• Declare the required clobbers when the block reads or writes hidden state.
• Prefer isolating architecture-specific asm behind small typed functions.

Inline assembly's correctness and portability are not guaranteed by Wave's type system alone.