p1275_uintptr2cell
ci[4] = p1275_uintptr2cell(arg1); /* Arg2: stack arg 1 */
ci[5] = p1275_uintptr2cell(arg2); /* Arg3: stack arg 2 */
ci[6] = p1275_uintptr2cell(arg3); /* Arg4: stack arg 3 */
ci[7] = p1275_uintptr2cell(arg4); /* Arg5: stack arg 4 */
ci[8] = p1275_uintptr2cell(arg5); /* Arg6: stack arg 5 */
cif[3 + nargs + 1] = p1275_uintptr2cell(symvalue);