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checked_add :: (a: $T, b: T) -> result: T, overflow: bool
#modify {
if T.type == .INTEGER return;
T = null;
}
{
overflow: bool;
result: T = a + b;
info := type_info(T);
if info.signed {
// (+A) + (+B) = −C
// (−A) + (−B) = +C
if ((a > 0) && (b > 0) && (result < 0)) || ((a < 0) && (b < 0) && (result > 0)) {
overflow = true;
}
} else {
if result < a {
overflow = true;
}
}
return result, overflow;
}
checked_sub :: (a: $T, b: T) -> result: T, overflow: bool
#modify {
if T.type == .INTEGER return;
T = null;
}
{
overflow: bool;
result: T = a - b;
info := type_info(T);
if info.signed {
// (+A) − (−B) = −C
// (−A) − (+B) = +C
if ((a > 0) && (b < 0) && (result < 0)) || ((a < 0) && (b > 0) && (result > 0)) {
overflow = true;
}
} else {
if result > a {
overflow = true;
}
}
return result, overflow;
}
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