[mirror_edk2.git] / EdkCompatibilityPkg / Foundation / Library / EfiCommonLib / Ia32 / LShiftU64.S

#/*++
#
#Copyright (c) 2006, Intel Corporation                                                         
#All rights reserved. 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.c
#
#Abstract:
#
#  64-bit left shift function for IA-32
#
#--*/
#
#include "EfiBind.h"
#---------------------------------------------------------------------------
    .686: 
    #.MODEL flat,C
    .code: 

#---------------------------------------------------------------------------
.globl ASM_PFX(LShiftU64)
#
#UINT64
#LShiftU64 (
#  IN UINT64   Operand,
#  IN UINTN    Count
#  )
#/*++
#
#Routine Description:
# 
#  This routine allows a 64 bit value to be left shifted by 32 bits and 
#  returns the shifted value.
#  Count is valid up 63. (Only Bits 0-5 is valid for Count)
#
#Arguments:
#
#  Operand - Value to be shifted
#  Count   - Number of times to shift left.
#  
#Returns:
#
#  Value shifted left identified by the Count.
#
#--*/
ASM_PFX(LShiftU64):

    movl   4(%esp), %eax # dword ptr Operand[0]
    movl   8(%esp), %edx # dword ptr Operand[4]

    #
    # CL is valid from 0 - 31. shld will move EDX:EAX by CL times but EAX is not touched
    # For CL of 32 - 63, it will be shifted 0 - 31 so we will move eax to edx later. 
    #
    movl   0xC(%esp), %ecx # Count
    andl   $63, %ecx
    shld   %cl, %eax, %edx
    shlb   %cl, %eax

    #
    # Since Count is 32 - 63, eax will have been shifted  by 0 - 31                                                     
    # If shifted by 32 or more, set lower 32 bits to zero.
    #
    cmpl   $32, %ecx
    jc     _LShiftU64_Done

    movl   %eax, %edx
    xorl   %eax, %eax

_LShiftU64_Done: 

    ret
#LShiftU64 ENDP
Commit	Line	Data
b962b6b5	1	#/*++
	2	#
	3	#Copyright (c) 2006, 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	# LShiftU64.c
	15	#
	16	#Abstract:
	17	#
	18	# 64-bit left shift function for IA-32
	19	#
	20	#--*/
	21	#
	22	#include "EfiBind.h"
	23	#---------------------------------------------------------------------------
	24	.686:
	25	#.MODEL flat,C
	26	.code:
	27
	28	#---------------------------------------------------------------------------
	29	.globl ASM_PFX(LShiftU64)
	30	#
	31	#UINT64
	32	#LShiftU64 (
	33	# IN UINT64 Operand,
	34	# IN UINTN Count
	35	# )
	36	#/*++
	37	#
	38	#Routine Description:
	39	#
	40	# This routine allows a 64 bit value to be left shifted by 32 bits and
	41	# returns the shifted value.
	42	# Count is valid up 63. (Only Bits 0-5 is valid for Count)
	43	#
	44	#Arguments:
	45	#
	46	# Operand - Value to be shifted
	47	# Count - Number of times to shift left.
	48	#
	49	#Returns:
	50	#
	51	# Value shifted left identified by the Count.
	52	#
	53	#--*/
	54	ASM_PFX(LShiftU64):
	55
	56	movl 4(%esp), %eax # dword ptr Operand[0]
	57	movl 8(%esp), %edx # dword ptr Operand[4]
	58
	59	#
	60	# CL is valid from 0 - 31. shld will move EDX:EAX by CL times but EAX is not touched
	61	# For CL of 32 - 63, it will be shifted 0 - 31 so we will move eax to edx later.
	62	#
	63	movl 0xC(%esp), %ecx # Count
	64	andl $63, %ecx
65	shld %cl, %eax, %edx
66	shlb %cl, %eax
67
68	#
69	# Since Count is 32 - 63, eax will have been shifted by 0 - 31
70	# If shifted by 32 or more, set lower 32 bits to zero.
71	#
72	cmpl $32, %ecx
73	jc _LShiftU64_Done
74
75	movl %eax, %edx
76	xorl %eax, %eax
77
78	_LShiftU64_Done:
79
80	ret
81	#LShiftU64 ENDP
82