1 /** @file 2 64-bit logical right shift function for IA-32 3 4 Copyright (c) 2006 - 2015, Intel Corporation. All rights reserved.<BR> 5 This program and the accompanying materials 6 are licensed and made available under the terms and conditions of the BSD License 7 which accompanies this distribution. The full text of the license may be found at 8 http://opensource.org/licenses/bsd-license.php. 9 10 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, 11 WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED. 12 13 **/ 14 15 16 17 18 /** 19 Shifts a 64-bit integer right between 0 and 63 bits. This high bits 20 are filled with zeros. The shifted value is returned. 21 22 This function shifts the 64-bit value Operand to the right by Count bits. The 23 high Count bits are set to zero. The shifted value is returned. 24 25 @param Operand The 64-bit operand to shift right. 26 @param Count The number of bits to shift right. 27 28 @return Operand >> Count 29 30 **/ 31 UINT64 32 EFIAPI 33 InternalMathRShiftU64 ( 34 IN UINT64 Operand, 35 IN UINTN Count 36 ) 37 { 38 _asm { 39 mov cl, byte ptr [Count] 40 xor edx, edx 41 mov eax, dword ptr [Operand + 4] 42 test cl, 32 43 jnz L0 44 mov edx, eax 45 mov eax, dword ptr [Operand + 0] 46 L0: 47 shrd eax, edx, cl 48 shr edx, cl 49 } 50 } 51 52
