audk/ArmPkg/Library/BaseMemoryLibVstm/Arm/CopyMem.S

115 lines
2.5 KiB
ArmAsm

#------------------------------------------------------------------------------
#
# CopyMem() worker for ARM
#
# This file started out as C code that did 64 bit moves if the buffer was
# 32-bit aligned, else it does a byte copy. It also does a byte copy for
# any trailing bytes. Update using VSTM/SLDM to do 128 byte copies.
#
# Copyright (c) 2008 - 2010, Apple Inc. 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.
#
#------------------------------------------------------------------------------
/**
Copy Length bytes from Source to Destination. Overlap is OK.
This implementation
@param Destination Target of copy
@param Source Place to copy from
@param Length Number of bytes to copy
@return Destination
VOID *
EFIAPI
InternalMemCopyMem (
OUT VOID *DestinationBuffer,
IN CONST VOID *SourceBuffer,
IN UINTN Length
)
**/
.text
.align 2
GCC_ASM_EXPORT(InternalMemCopyMem)
ASM_PFX(InternalMemCopyMem):
stmfd sp!, {r4, r9, lr}
tst r0, #3
mov r4, r0
mov r9, r0
mov ip, r2
mov lr, r1
movne r0, #0
bne L4
tst r1, #3
movne r3, #0
moveq r3, #1
cmp r2, #127
movls r0, #0
andhi r0, r3, #1
L4:
cmp r4, r1
bcc L26
bls L7
rsb r3, r1, r4
cmp ip, r3
bcc L26
cmp ip, #0
beq L7
add r9, r4, ip
add lr, ip, r1
b L16
L29:
sub ip, ip, #8
cmp ip, #7
ldrd r2, [lr, #-8]!
movls r0, #0
cmp ip, #0
strd r2, [r9, #-8]!
beq L7
L16:
cmp r0, #0
bne L29
sub r3, lr, #1
sub ip, ip, #1
ldrb r3, [r3, #0]
sub r2, r9, #1
cmp ip, #0
sub r9, r9, #1
sub lr, lr, #1
strb r3, [r2, #0]
bne L16
b L7
L11:
ldrb r3, [lr], #1
sub ip, ip, #1
strb r3, [r9], #1
L26:
cmp ip, #0
beq L7
L30:
cmp r0, #0
beq L11
sub ip, ip, #128 // 32
cmp ip, #127 // 31
vldm lr!, {d0-d15}
movls r0, #0
cmp ip, #0
vstm r9!, {d0-d15}
bne L30
L7:
dsb
mov r0, r4
ldmfd sp!, {r4, r9, pc}