RShiftU64.S revision 57246fe073e7946e03387576fca76eba86b51694 
1#------------------------------------------------------------------------------
2#
3# Copyright (c) 2006 - 2008, Intel Corporation
4# All rights reserved. This program and the accompanying materials
5# are licensed and made available under the terms and conditions of the BSD License
6# which accompanies this distribution.  The full text of the license may be found at
7# http://opensource.org/licenses/bsd-license.php
8#
9# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
10# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
11#
12# Module Name:
13#
14#   RShiftU64.S
15#
16# Abstract:
17#
18#   64-bit logical right shift function for IA-32
19#
20#------------------------------------------------------------------------------
21
22    .686:
23    .code:
24
25.globl ASM_PFX(InternalMathRShiftU64)
26
27#------------------------------------------------------------------------------
28# UINT64
29# EFIAPI
30# InternalMathRShiftU64 (
31#   IN      UINT64                    Operand,
32#   IN      UINTN                     Count
33#   );
34#------------------------------------------------------------------------------
35ASM_PFX(InternalMathRShiftU64):
36    movb    12(%esp), %cl               # cl <- Count
37    xorl    %edx, %edx
38    movl    8(%esp), %eax
39    testb   $32, %cl                    # Count >= 32?
40    cmovz   %eax, %edx
41    cmovz   0x4(%esp), %eax
42    shrdl   %cl, %edx, %eax
43    shr     %cl, %edx
44    ret
45