CloverBootloader/MdePkg/Library/BaseMemoryLibOptDxe/Arm/SetMem.asm

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;------------------------------------------------------------------------------
;
; Copyright (c) 2016, Linaro Ltd. All rights reserved.<BR>
;
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
;------------------------------------------------------------------------------
EXPORT InternalMemZeroMem
EXPORT InternalMemSetMem
EXPORT InternalMemSetMem16
EXPORT InternalMemSetMem32
EXPORT InternalMemSetMem64
AREA SetMem, CODE, READONLY, CODEALIGN, ALIGN=5
THUMB
InternalMemSetMem16
uxth r2, r2
lsl r1, r1, #1
orr r2, r2, r2, lsl #16
b B0
InternalMemSetMem32
lsl r1, r1, #2
b B0
InternalMemSetMem64
lsl r1, r1, #3
b B1
ALIGN 32
InternalMemSetMem
uxtb r2, r2
orr r2, r2, r2, lsl #8
orr r2, r2, r2, lsl #16
b B0
InternalMemZeroMem
movs r2, #0
B0
mov r3, r2
B1
push {r4, lr}
cmp r1, #16 ; fewer than 16 bytes of input?
add r1, r1, r0 ; r1 := dst + length
add lr, r0, #16
blt L2
bic lr, lr, #15 ; align output pointer
str r2, [r0] ; potentially unaligned store of 4 bytes
str r3, [r0, #4] ; potentially unaligned store of 4 bytes
str r2, [r0, #8] ; potentially unaligned store of 4 bytes
str r3, [r0, #12] ; potentially unaligned store of 4 bytes
beq L1
L0
add lr, lr, #16 ; advance the output pointer by 16 bytes
subs r4, r1, lr ; past the output?
blt L3 ; break out of the loop
strd r2, r3, [lr, #-16] ; aligned store of 16 bytes
strd r2, r3, [lr, #-8]
bne L0 ; goto beginning of loop
L1
pop {r4, pc}
L2
subs r4, r1, lr
L3
adds r4, r4, #16
subs r1, r1, #8
cmp r4, #4 ; between 4 and 15 bytes?
blt L4
cmp r4, #8 ; between 8 and 15 bytes?
str r2, [lr, #-16] ; overlapping store of 4 + (4 + 4) + 4 bytes
itt gt
strgt r3, [lr, #-12]
strgt r2, [r1]
str r3, [r1, #4]
pop {r4, pc}
L4
cmp r4, #2 ; 2 or 3 bytes?
strb r2, [lr, #-16] ; store 1 byte
it ge
strhge r2, [r1, #6] ; store 2 bytes
pop {r4, pc}
END