let c_int_bounds = function
| UInt8 -> (Big_int.zero_big_int,Big_int.big_int_of_string "256")
| SInt8 -> (Big_int.big_int_of_string "-128",
Big_int.big_int_of_string "128")
| UInt16 -> (Big_int.zero_big_int,
Big_int.big_int_of_string "65536")
| SInt16 -> (Big_int.big_int_of_string "-32768",
Big_int.big_int_of_string "32768")
| UInt32 -> (Big_int.zero_big_int,
Big_int.big_int_of_string "4294967296")
| SInt32 -> (Big_int.big_int_of_string "-2147483648" ,
Big_int.big_int_of_string "2147483648" )
| UInt64 -> (Big_int.zero_big_int ,
Big_int.big_int_of_string "18446744073709551616" )
| SInt64 -> (Big_int.big_int_of_string "-9223372036854775808" ,
Big_int.big_int_of_string "9223372036854775808" )