Optimized HighBitSetXX() functions

[mirror_edk2.git] / MdePkg / Library / BaseLib / Ia32 / DivU64x64Remainder.c

/** @file\r
  Calculate the quotient of a 64-bit integer by a 64-bit integer and returns\r
  both the quotient and the remainderSet error flag for all division functions\r
\r
  Copyright (c) 2006, Intel Corporation<BR>\r
  All rights reserved. This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#if _MSC_EXTENSIONS\r
\r
UINT64\r
EFIAPI\r
InternalMathDivRemU64x64 (\r
  IN      UINT64                    Dividend,\r
  IN      UINT64                    Divisor,\r
  OUT     UINT64                    *Remainder    OPTIONAL\r
  )\r
{\r
  _asm {\r
    mov     edx, dword ptr [Dividend + 4]\r
    mov     eax, dword ptr [Dividend + 0]   // edx:eax <- dividend\r
    mov     edi, edx\r
    mov     esi, eax                    // edi:esi <- dividend\r
    mov     ebx, dword ptr [Divisor + 0]   // ecx:ebx <- divisor\r
BitLoop:\r
    shr     edx, 1\r
    rcr     eax, 1\r
    shrd    ebx, ecx, 1\r
    shr     ecx, 1\r
    jnz     BitLoop\r
    div     ebx\r
    mov     ebx, eax                    // ebx <- quotient\r
    mov     ecx, dword ptr [Divisor + 4]\r
    mul     dword ptr [Divisor]\r
    imul    ecx, ebx\r
    add     edx, ecx\r
    mov     ecx, Remainder\r
    jc      TooLarge                   // product > 2^64\r
    cmp     edi, edx                    // compare high 32 bits\r
    ja      Correct\r
    jb      TooLarge                   // product > dividend\r
    cmp     esi, eax\r
    jae     Correct                    // product <= dividend\r
TooLarge:\r
    dec     ebx                         // adjust quotient by -1\r
    jecxz   Return                     // return if Remainder == NULL\r
    sub     eax, dword ptr [Divisor + 0]\r
    sbb     edx, dword ptr [Divisor + 4]\r
Correct:\r
    jecxz   Return\r
    sub     esi, eax\r
    sbb     edi, edx                    // edi:esi <- remainder\r
    mov     [ecx], esi\r
    mov     [ecx + 4], edi\r
Return:\r
    mov     eax, ebx                    // eax <- quotient\r
    xor     edx, edx\r
  }\r
}\r
\r
#endif\r