C++ Arbitrary Precision Integer Arithmetic

The C++ Arbitrary Precision Integer library supports all standard arithmetic, logical bitwise, shifts, and comparison operations. Note that for shifting that >> and << are logical, and the .ashr(x) function implements arithmetic right shift. The output types of an operation are wider than their operands as necessary to hold the result. Operands of ap_int, and ap_uint type, as well as operands of different widths can be mixed freely. By default ap_int will be self-extended to the appropriate width for an operation, while ap_uint will be zero-extended. When mixing ap_int and ap_uint in an arithmetic operation the resulting type will always be ap_int. Some of this behaviour is demonstrated in the example below.

#include "hls/ap_fixpt.hpp"
#include "hls/ap_int.hpp"
#include <iostream>
#include <stdio.h>

using namespace hls;

    //...
    ap_int<8> a = 7;
    ap_int<12> b = 100;
    ap_uint<7> c = 3;

    // Multiply expands to the sum of a and b's width
    ap_int<20> d = a * b;
    std::cout << "d = " << d << std::endl;

    // Add result in max of widths + 1
    ap_int<13> e = a + b;
    std::cout << "e = " << e << std::endl;

    // Logical bitwise ops result in max of widths
    ap_int<12> f = a & b;
    std::cout << "f = " << f << std::endl;

    // Mixing ap_int and ap_uint results in ap_int
    ap_int<9> g = a + c;
    std::cout << "g = " << g << std::endl;

    // ap_(u)int types can be mixed freely with integral types
    ap_int<33> h = -1 - a;
    std::cout << "h = " << h << std::endl;