diff options
Diffstat (limited to 'checklink/Safe.ml')
-rw-r--r-- | checklink/Safe.ml | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/checklink/Safe.ml b/checklink/Safe.ml new file mode 100644 index 00000000..efcd3bd6 --- /dev/null +++ b/checklink/Safe.ml @@ -0,0 +1,25 @@ +(* "Hacker's Delight", section 2.12 *) + +let ( + ) x y = + let z = x + y in + (* Overflow occurs iff x and y have same sign and z's sign is different *) + if (z lxor x) land (z lxor y) < 0 + then raise Exc.IntOverflow + else z + +let ( - ) x y = + let z = x - y in + (* Overflow occurs iff x and y have opposite signs and z and x have + opposite signs *) + if (x lxor y) land (z lxor x) < 0 + then raise Exc.IntOverflow + else z + +let ( * ) x y = + let z = x * y in + if (x = min_int && y < 0) || (y <> 0 && z / y <> x) + then raise Exc.IntOverflow + else z + +let of_int32 = Safe32.to_int +let to_int32 = Safe32.of_int |