"CreateFileA" in NT based systems is nothing but a little wrapper around "CreateFileW". So it's fairly short:

77e5b476 public CreateFileA:              ; function entry point 77e5b476   push    ebp 77e5b477   mov     ebp, esp 77e5b479   push    dword ptr [ebp+8] 77e5b47c   call    -$ef ($77e5b392) 77e5b47c 77e5b481   test    eax, eax 77e5b483   jz      loc_77e7b42c 77e5b483 77e5b489   push    dword ptr [ebp+$20] 77e5b48c   push    dword ptr [ebp+$1c] 77e5b48f   push    dword ptr [ebp+$18] 77e5b492   push    dword ptr [ebp+$14] 77e5b495   push    dword ptr [ebp+$10] 77e5b498   push    dword ptr [ebp+$c] 77e5b49b   push    dword ptr [eax+4] 77e5b49e   call    -$412 ($77e5b091)      ; CreateFileW (kernel32.dll) 77e5b49e 77e5b4a3 loc_77e5b4a3: 77e5b4a3   pop     ebp 77e5b4a4   ret     $1c 77e5b4a4 77e5b4a4 ; --------------------------------------------------------- 77e5b4a4 77e7b42c loc_77e7b42c: 77e7b42c   or      eax, -1 77e7b42f   jmp     loc_77e5b4a3