audk/ArmPkg/Library/BaseMemoryLibStm/Arm/CopyMem.asm

115 lines
2.3 KiB
NASM
Executable File

;------------------------------------------------------------------------------
;
; 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. It was updated to do 32-byte copies using stm/ldm.
;
; 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
)
**/
EXPORT InternalMemCopyMem
AREA AsmMemStuff, CODE, READONLY
InternalMemCopyMem
stmfd sp!, {r4-r11, lr}
tst r0, #3
mov r11, r0
mov r10, r0
mov ip, r2
mov lr, r1
movne r0, #0
bne L4
tst r1, #3
movne r3, #0
moveq r3, #1
cmp r2, #31
movls r0, #0
andhi r0, r3, #1
L4
cmp r11, r1
bcc L26
bls L7
rsb r3, r1, r11
cmp ip, r3
bcc L26
cmp ip, #0
beq L7
add r10, r11, 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, [r10, #-8]!
beq L7
L16
cmp r0, #0
bne L29
sub r3, lr, #1
sub ip, ip, #1
ldrb r3, [r3, #0]
sub r2, r10, #1
cmp ip, #0
sub r10, r10, #1
sub lr, lr, #1
strb r3, [r2, #0]
bne L16
b L7
L11
ldrb r3, [lr], #1
sub ip, ip, #1
strb r3, [r10], #1
L26
cmp ip, #0
beq L7
L30
cmp r0, #0
beq L11
sub ip, ip, #32
cmp ip, #31
ldmia lr!, {r2-r9}
movls r0, #0
cmp ip, #0
stmia r10!, {r2-r9}
bne L30
L7
mov r0, r11
ldmfd sp!, {r4-r11, pc}
END