On 2024-12-12 23:58, Charles Oliver Nutter wrote:
Question two: Am I losing the benefits of *Exact if I use the following
code to "pre-check" for overflow?
long high = Math.multiplyHigh(a, b);
if (high == 0) return Math.multiplyExact(a, b);
return bigIntegerMultiply(a, b);
For your specific multiplication use case you might try with
long high = Math.multiplyHigh(a, b);
long low = a * b;
if (high == 0) return low;
return "the big integer consisting of high and low";
It might be possible that the multiplyHigh() and * on the same operands,
when appearing adjacent to each other, get optimized to just one
instruction.
And if not, they might be executed "in parallel" inside the CPU.
HTH
Raffaello
