Multiplication of two uint256

Question

How do I compute the multiplication of two uint256 so the result doesn't overflow?

In the end, this multiplication is an intermediate step within a larger operation, in case this extra piece of info helps.

Fyi, I'm not looking to change the order of the operations nor remove any padding.

uint256 a = 10864869065949319007600000000000000000000;
uint256 b = 3300000000000000000000000000000000000000;
uint256 c = 10859952502829164007600000000000000000000;

uint256 result = (a * b) / c;

The overflow occurs in (a * b).

Assembly is more than welcomed if it produces the expected result. Thanks!

Answer 1

Using https://github.com/SimonSuckut/Solidity_Uint512/blob/main/contracts/Uint512.sol

(uint r0, uint r1) = a.mul256x256(b);
uint result = r0.div512x256(r1, c);