ARM_ADD_I
emit(ARM_ADD_I(tmp[0], src, add_off), ctx);
emit(ARM_ADD_I(tmp[1], r_array, off), ctx);
emit(ARM_ADD_I(tmp[1], tmp[1], ctx->prologue_bytes), ctx);
emit(ARM_ADD_I(ARM_SP, ARM_SP, imm8m(24)), ctx); // callee clean
emit(ARM_ADD_I(ARM_SP, ARM_SP, 8), ctx);
emit(ARM_ADD_I(ARM_SP, ARM_SP, 8), ctx);