// Stream B1 (fibers) step B1.0a — LOCK commit for `abi(.pure)`.
//
// An `abi(.pure)` function has no calling-convention prologue/epilogue/frame
// and no implicit `__sx_ctx`: its body is a single asm block that sets the
// return register and emits its own `ret`. This is the substrate the per-arch
// fiber context-switch is built on (design §4.6) — a `.c` epilogue would
// restore SP from the wrong stack across a switch (SP-in ≠ SP-out by design).
//
// This commit only plumbs the `is_pure` flag through lowering; LLVM emission
// (the `naked` attribute + asm-only body) is NOT implemented yet, so emit bails
// LOUDLY (build-gating, nonzero exit) rather than emit a framed body. The bail
// is at the function level, before any asm/instruction selection, so it is
// host-independent (no `.build` target pin needed until B1.0b adds emission).
// B1.0b flips this to a green, aarch64-pinned end-to-end run.
answer :: () -> i64 abi(.pure) {
    asm volatile {
        #string ASM
        mov x0, #42
        ret
ASM
    };
}

main :: () -> i64 { return answer(); }