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/* SPDX-License-Identifier: GPL-2.0 */
/*
* String handling functions for PowerPC32
*
* Copyright (C) 1996 Paul Mackerras.
*
*/
#include <asm/ppc_asm.h>
#include <asm/export.h>
#include <asm/cache.h>
.text
CACHELINE_BYTES = L1_CACHE_BYTES
LG_CACHELINE_BYTES = L1_CACHE_SHIFT
CACHELINE_MASK = (L1_CACHE_BYTES-1)
_GLOBAL(__clear_user)
/*
* Use dcbz on the complete cache lines in the destination
* to set them to zero. This requires that the destination
* area is cacheable.
*/
cmplwi cr0, r4, 4
mr r10, r3
li r3, 0
blt 7f
11: stw r3, 0(r10)
beqlr
andi. r0, r10, 3
add r11, r0, r4
subf r6, r0, r10
clrlwi r7, r6, 32 - LG_CACHELINE_BYTES
add r8, r7, r11
srwi r9, r8, LG_CACHELINE_BYTES
addic. r9, r9, -1 /* total number of complete cachelines */
ble 2f
xori r0, r7, CACHELINE_MASK & ~3
srwi. r0, r0, 2
beq 3f
mtctr r0
4: stwu r3, 4(r6)
bdnz 4b
3: mtctr r9
li r7, 4
10: dcbz r7, r6
addi r6, r6, CACHELINE_BYTES
bdnz 10b
clrlwi r11, r8, 32 - LG_CACHELINE_BYTES
addi r11, r11, 4
2: srwi r0 ,r11 ,2
mtctr r0
bdz 6f
1: stwu r3, 4(r6)
bdnz 1b
6: andi. r11, r11, 3
beqlr
mtctr r11
addi r6, r6, 3
8: stbu r3, 1(r6)
bdnz 8b
blr
7: cmpwi cr0, r4, 0
beqlr
mtctr r4
addi r6, r10, -1
9: stbu r3, 1(r6)
bdnz 9b
blr
90: mr r3, r4
blr
91: add r3, r10, r4
subf r3, r6, r3
blr
EX_TABLE(11b, 90b)
EX_TABLE(4b, 91b)
EX_TABLE(10b, 91b)
EX_TABLE(1b, 91b)
EX_TABLE(8b, 91b)
EX_TABLE(9b, 91b)
EXPORT_SYMBOL(__clear_user)
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