MdePkg/Library/BaseLib/Ia32/LShiftU64.S

#------------------------------------------------------------------------------
#
# Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>
# This program and the accompanying materials
# are licensed and made available under the terms and conditions of the BSD License
# which accompanies this distribution.  The full text of the license may be found at
# http://opensource.org/licenses/bsd-license.php.
#
# THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
# WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
#
# Module Name:
#
#   LShiftU64.S
#
# Abstract:
#
#   64-bit left shift function for IA-32
#
#------------------------------------------------------------------------------

ASM_GLOBAL ASM_PFX(InternalMathLShiftU64)

#------------------------------------------------------------------------------
# UINT64
# EFIAPI
# InternalMathLShiftU64 (
#   IN      UINT64                    Operand,
#   IN      UINTN                     Count
#   );
#------------------------------------------------------------------------------
ASM_PFX(InternalMathLShiftU64):
    movb    12(%esp), %cl
    xorl    %eax, %eax
    movl    4(%esp), %edx
    testb   $32, %cl                    # Count >= 32?
    jnz     L0
    movl    %edx, %eax
    movl    0x8(%esp), %edx
L0:
    shld    %cl, %eax, %edx
    shl     %cl, %eax
    ret