Line https://github.com/ish-app/ish/blob/master/jit/gadgets-aarch... and the subsequent lines sum it up nicely:

        # also hell {{{
        .ifin(\op, bt)
            read_bullshit \size, \op\size\()_mem
        .endifin
        .ifin(\op, btc,bts,btr)
            write_bullshit \size, \op\size\()_mem
        .endifin
        # }}}