Function mulNoAlias [src]

rma = a * b rma may not alias with a or b. a and b may alias with each other. Asserts the result fits in rma. An upper bound on the number of limbs needed by rma is given by a.limbs.len + b.limbs.len. If allocator is provided, it will be used for temporary storage to improve multiplication performance. error.OutOfMemory is handled with a fallback algorithm.

Prototype

pub fn mulNoAlias(rma: *Mutable, a: Const, b: Const, allocator: ?Allocator) void

Parameters

rma: *Mutablea: Constb: Constallocator: ?Allocator

Source

  pub fn mulNoAlias(rma: *Mutable, a: Const, b: Const, allocator: ?Allocator) void {
    assert(rma.limbs.ptr != a.limbs.ptr); // illegal aliasing
    assert(rma.limbs.ptr != b.limbs.ptr); // illegal aliasing

    if (a.limbs.len == 1 and b.limbs.len == 1) {
        const ov = @mulWithOverflow(a.limbs[0], b.limbs[0]);
        rma.limbs[0] = ov[0];
        if (ov[1] == 0) {
            rma.len = 1;
            rma.positive = (a.positive == b.positive);
            return;
        }
    }

    @memset(rma.limbs[0 .. a.limbs.len + b.limbs.len], 0);

    llmulacc(.add, allocator, rma.limbs, a.limbs, b.limbs);

    rma.normalize(a.limbs.len + b.limbs.len);
    rma.positive = (a.positive == b.positive);
}  