我在看這個問題:How to implement multiplication without using multiplication operator in .NET,實際上有很多樂趣,試圖想辦法繁殖而不使用*。有人可以向我解釋這段代碼嗎?
但是我在這個答案上一直在撓頭。我不知道這段代碼是怎麼回事。
有人可以解釋給我嗎?
using System;
using System.Runtime.InteropServices;
delegate uint BinaryOp(uint a, uint b);
static class Program
{
[DllImport("kernel32.dll", SetLastError = true)]
static extern bool VirtualProtect(
IntPtr address, IntPtr size, uint protect, out uint oldProtect);
static void Main()
{
var bytes = IntPtr.Size == sizeof(int) ? //32-bit? It's slower BTW
new byte[] {0x8B, 0x44, 0x24, 0x04, 0x0F, 0xAF, 0x44, 0x24, 0x08, 0xC3}
: new byte[] {0x0F, 0xAF, 0xCA, 0x8B, 0xC1, 0xC3};
var handle = GCHandle.Alloc(bytes, GCHandleType.Pinned);
try
{
uint old;
VirtualProtect(handle.AddrOfPinnedObject(),
(IntPtr)bytes.Length, 0x40, out old);
var action = (BinaryOp)Marshal.GetDelegateForFunctionPointer(
handle.AddrOfPinnedObject(), typeof(BinaryOp));
var temp = action(3, 2); //6!
}
finally { handle.Free(); }
}
}
此代碼的信用轉至Mehrdad。
實際上是本機機器碼,而不是彙編語言。 – 2011-05-07 11:51:11