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This is an example of documentation generated by ZigDoc, an alternative to Zig's built-in Auto Doc feature. See also examples in other modes/formats. The project being documented here (as the example) is the Zig standard library. Public Function

bitCountTwosComp

Doc Source

Public Function

std.math.big.int.Const.bitCountTwosComp

pub fn bitCountTwosComp(self: Const) usize

Returns the number of bits required to represent the integer in twos-complement form.

If the integer is negative the value returned is the number of bits needed by a signed integer to represent the value. If positive the value is the number of bits for an unsigned integer. Any unsigned integer will fit in the signed integer with bitcount one greater than the returned value.

e.g. -127 returns 8 as it will fit in an i8. 127 returns 7 since it fits in a u7.

Params

self: Const

File

math/big/int.zig:2228

    pub fn bitCountTwosComp(self: Const) usize {
        var bits = self.bitCountAbs();

        // If the entire value has only one bit set (e.g. 0b100000000) then the negation in twos
        // complement requires one less bit.
        if (!self.positive) block: {
            bits += 1;

            if (@popCount(self.limbs[self.limbs.len - 1]) == 1) {
                for (self.limbs[0 .. self.limbs.len - 1]) |limb| {
                    if (@popCount(limb) != 0) {
                        break :block;
                    }
                }

                bits -= 1;
            }
        }

        return bits;
    }