求助，Montgomery 乘法比暴力乘法取模慢是个啥回事啊（至少在我的机子上是这样的）

// Qiuly AK IOI!
#include<cstdio>
#include<cstring>
#include<cctype>
#include<cmath>
#include<iostream>
#include<algorithm>
#include<random>
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
using namespace std;
typedef int ll;
typedef unsigned int ul;
typedef long long int li;
typedef unsigned long long int ull;
const ll MAXN=262151,MOD=998244353,G=3,INVG=332748118;
struct ModInt{
	ll v;
	ModInt(ll v=0)
	{
		this->v=v;
	}
};
struct Mont{
	static ul mod,inv,r2;
	ul v;
	Mont(ll x=0)
	{
		v=reduce((ull)x*r2);
	}
	inline static void set(ull md)
	{
		mod=inv=md,inv*=2-inv*md,inv*=2-inv*md;
		inv*=2-inv*md,inv*=2-inv*md,r2=-(ull)(md)%md;
	}
	inline ul reduce(ull x)
	{
		ul y=(ul)(x>>32)-(ul)(((ull)((ul)x*inv)*mod)>>32);
		return (ll)(y)<0?y+mod:y;
	}
	inline Mont operator *(Mont &rhs)
	{
		v=reduce((ull)v*rhs.v);
		return *this;
	}
	inline ul get()
	{
		return reduce(v);
	}
};
ul Mont::mod,Mont::inv,Mont::r2;
ll x[100000001],y[100000001];
inline void fast()
{
	Mont r,r2;
	for(register int i=1;i<=10000000;i++)
	{
		r=Mont(x[i]),r2=Mont(y[i]),r=r*r2;
	}
}
inline void slow()
{
	ll x01;
	for(register int i=1;i<=10000000;i++)
	{
		x01=(li)x[i]*y[i]%MOD;
	}
}
int main()
{
	Mont::set(MOD);
	mt19937 mt(123123);
	for(register int i=1;i<=10000000;i++)
	{
		x[i]=mt()%MOD,y[i]=mt()%MOD;
	}
	clock_t t0=clock();
	fast();
	clock_t t1=clock();
	slow();
	clock_t t2=clock();
	printf("%.3lf s\n%.3lf s\n",(double)(t1-t0)/CLOCKS_PER_SEC,(double)(t2-t1)/CLOCKS_PER_SEC);
}