.net framework 2.0

• bir bit count tablosunu initialize etmek icin .net framework 2.0 64-bit'te:
  
  c#
  
  byte[] bitcounts = new byte[256];
  for (int n = 0; n < 256; n++) for (int i = n; i > 0; i >>= 1) bitcounts[n] += (byte)(i & 1);
  
  c# compiler'in urettigi x64 kodu:
  
  mov r11,rax
  xor r8d,r8d
  xor r9d,r9d
  xchg ax,ax
  mov edx,r8d
  test edx,edx
  jle 00000642`80150200
  xchg ax,ax
  xchg ax,ax
  xchg ax,ax
  mov al,byte ptr [r11+r9+10h]
  movzx ecx,al
  mov eax,edx
  and eax,1
  movzx eax,al
  add ecx,eax
  mov byte ptr [r11+r9+10h],cl
  sar edx,1
  test edx,edx
  jg 00000642`801501e0
  xchg ax,ax
  add r8d,1
  add r9,1
  cmp r9,100h
  jl 00000642`801501d0
  
  bu da ayni kodun c hali:
  
  unsigned char bitcounts[256];
  for (int n = 0; n < 256; n++) for (int i = n; i > 0; i >>= 1) bitcounts[n] += i & 1;
  
  visual studio 2005 c/c++ compiler'inin native olarak x64 icin urettigi kod:
  
  xor r8d,r8d
  xchg ax,ax
  test r8d,r8d
  mov ecx,r8d
  je main+18dh (40118dh)
  movzx edx,byte ptr [rbx]
  xchg ax,ax
  xchg ax,ax
  movzx eax,cl
  and al,1
  add dl,al
  sar ecx,1
  jne main+180h (401180h)
  mov byte ptr [rbx],dl
  add r8d,1
  add rbx,1
  cmp r8d,100h
  jl main+170h (401170h)
  
  netice olarak diyorum ki .net framework gibi luks bir ortam icin super.
  
  java'nin jit'inin (eger 64-bit destekliyorsa) ne marifetler yaptigini da gormek isterdim ama o imkanimiz yok sanirim.