UefiCpuPkg: Move AsmRelocateApLoopStart from Mpfuncs.nasm to AmdSev.nasm

[mirror_edk2.git] / CryptoPkg / Library / IntrinsicLib / Ia32 / MathRShiftU64.c

/** @file\r
  64-bit Math Worker Function.\r
  The 32-bit versions of C compiler generate calls to library routines\r
  to handle 64-bit math. These functions use non-standard calling conventions.\r
\r
Copyright (c) 2014, Intel Corporation. All rights reserved.<BR>\r
SPDX-License-Identifier: BSD-2-Clause-Patent\r
\r
**/\r
\r
/*\r
 * Shifts a 64-bit unsigned value right by a certain number of bits.\r
 */\r
__declspec(naked) void __cdecl\r
_aullshr (\r
  void\r
  )\r
{\r
  _asm {\r
    ;\r
    ; Checking: Only handle 64bit shifting or more\r
    ;\r
    cmp     cl, 64\r
    jae     _Exit\r
\r
    ;\r
    ; Handle shifting between 0 and 31 bits\r
    ;\r
    cmp     cl, 32\r
    jae     More32\r
    shrd    eax, edx, cl\r
    shr     edx, cl\r
    ret\r
\r
    ;\r
    ; Handle shifting of 32-63 bits\r
    ;\r
More32:\r
    mov     eax, edx\r
    xor     edx, edx\r
    and     cl, 31\r
    shr     eax, cl\r
    ret\r
\r
    ;\r
    ; Invalid number (less  then 32bits), return 0\r
    ;\r
\r
_Exit:\r
    xor     eax, eax\r
    xor     edx, edx\r
    ret\r
  }\r
}\r