current

    pub inline fn current() S390x {
        var ctx: S390x = undefined;
        asm volatile (
            \\ stmg %%r0, %%r15, 0(%%r2)
            \\ epsw %%r0, %%r1
            \\ stm %%r0, %%r1, 128(%%r2)
            \\ larl %%r0, .
            \\ stg %%r0, 136(%%r2)
            :
            : [ctx] "{r2}" (&ctx),
            : .{ .r0 = true, .r1 = true, .memory = true });
        return ctx;
    }