C#指针未解决问题

考虑以下代码：

C# code

  

   
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   unsafe
    { 
   byte
    b 
   =
    
   3
   ; 
   double
    d 
   =
    
   10.0
   ; 
   int
    i 
   =
    
   5
   ; 
   byte
   *
    pb 
   =
    
   &
   b; 
   double
   *
    pd 
   =
    
   &
   d; 
   int
   *
    pi 
   =
    
   &
   i; Console.WriteLine(
   "
   Address of b is 0x{0:X},size is {1},value is {2}
   "
   , (
   uint
   )pb, 
   sizeof
   (
   byte
   ), b); Console.WriteLine(
   "
   Address of d is 0x{0:X},size is {1},value is {2}
   "
   , (
   uint
   )pd, 
   sizeof
   (
   double
   ), d); Console.WriteLine(
   "
   Address of i is 0x{0:X},size is {1},value is {2}
   "
   , (
   uint
   )pi, 
   sizeof
   (
   int
   ), i); Console.WriteLine(
   "
   Address of pb is 0x{0:X},size is {1},value is 0x{2:X}
   "
   , (
   uint
   )
   &
   pb, 
   sizeof
   (
   byte
   *
   ), (
   uint
   )pb); Console.WriteLine(
   "
   Address of pd is 0x{0:X},size is {1},value is 0x{2:X}
   "
   , (
   uint
   )
   &
   pd, 
   sizeof
   (
   double
   *
   ), (
   uint
   )pd); Console.WriteLine(
   "
   Address of pi is 0x{0:X},size is {1},value is 0x{2:X}
   "
   , (
   uint
   )
   &
   pi, 
   sizeof
   (
   int
   *
   ), (
   uint
   )pi); } 

  

在我机子上显示的输出结果是
Addressofbis0x12F46C,sizeis1,valueis3
Addressofdis0x12F464,sizeis8,valueis10
Addressofiis0x12F460,sizeis4,valueis5
Addressofpbis0x12F45C,sizeis4,valueis0x12F46C
Addressofpdis0x12F458,sizeis4,valueis0x12F464
Addressofpiis0x12F454,sizeis4,valueis0x12F460

现在我的问题是：看代码，堆栈应该是从高地址向低地址向下填充，byte只占1个字节，而32位处理器系统堆栈的内存块总是按照4字节的倍数进行分配的。b的地址是0x12F46C，那么b这个值应该存储在0x12F468~0x12F46B中，占4个字节，然后为d分配内存，double类型占8个个字节，其地址应该是0x12F468,d应该存储在0x12F460~0x12F467中，但为什么输出结果b占了8个字节的内存而d却只占了4个字节的内存呢。
另外如果把代码的最后三行去掉，即变成

C# code

  

   
<!--

Code highlighting produced by Actipro CodeHighlighter (freeware)
http://www.CodeHighlighter.com/

-->
    
   unsafe
    { 
   byte
    b 
   =
    
   3
   ; 
   double
    d 
   =
    
   10.0
   ; 
   int
    i 
   =
    
   5
   ; 
   byte
   *
    pb 
   =
    
   &
   b; 
   double
   *
    pd 
   =
    
   &
   d; 
   int
   *
    pi 
   =
    
   &
   i; Console.WriteLine(
   "
   Address of b is 0x{0:X},size is {1},value is {2}
   "
   , (
   uint
   )pb, 
   sizeof
   (
   byte
   ), b); Console.WriteLine(
   "
   Address of d is 0x{0:X},size is {1},value is {2}
   "
   , (
   uint
   )pd, 
   sizeof
   (
   double
   ), d); Console.WriteLine(
   "
   Address of i is 0x{0:X},size is {1},value is {2}
   "
   , (
   uint
   )pi, 
   sizeof
   (
   int
   ), i); } 

  

输出结果为
Addressofbis0x12F45C,sizeis1,valueis3
Addressofdis0x12F460,sizeis8,valueis10
Addressofiis0x12F468,sizeis4,valueis5
内存分配变成了从低地址到高地址向上填充，但此时b占了4个字节，d占了8个字节，何解？