mem32.S
1.66 KB
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/*
* String handling functions.
*
* Copyright IBM Corp. 2012
*/
#include <linux/linkage.h>
/*
* memset implementation
*
* This code corresponds to the C construct below. We do distinguish
* between clearing (c == 0) and setting a memory array (c != 0) simply
* because nearly all memset invocations in the kernel clear memory and
* the xc instruction is preferred in such cases.
*
* void *memset(void *s, int c, size_t n)
* {
* if (likely(c == 0))
* return __builtin_memset(s, 0, n);
* return __builtin_memset(s, c, n);
* }
*/
ENTRY(memset)
basr %r5,%r0
.Lmemset_base:
ltr %r4,%r4
bzr %r14
ltr %r3,%r3
jnz .Lmemset_fill
ahi %r4,-1
lr %r3,%r4
srl %r3,8
ltr %r3,%r3
lr %r1,%r2
je .Lmemset_clear_rest
.Lmemset_clear_loop:
xc 0(256,%r1),0(%r1)
la %r1,256(%r1)
brct %r3,.Lmemset_clear_loop
.Lmemset_clear_rest:
ex %r4,.Lmemset_xc-.Lmemset_base(%r5)
br %r14
.Lmemset_fill:
stc %r3,0(%r2)
chi %r4,1
lr %r1,%r2
ber %r14
ahi %r4,-2
lr %r3,%r4
srl %r3,8
ltr %r3,%r3
je .Lmemset_fill_rest
.Lmemset_fill_loop:
mvc 1(256,%r1),0(%r1)
la %r1,256(%r1)
brct %r3,.Lmemset_fill_loop
.Lmemset_fill_rest:
ex %r4,.Lmemset_mvc-.Lmemset_base(%r5)
br %r14
.Lmemset_xc:
xc 0(1,%r1),0(%r1)
.Lmemset_mvc:
mvc 1(1,%r1),0(%r1)
/*
* memcpy implementation
*
* void *memcpy(void *dest, const void *src, size_t n)
*/
ENTRY(memcpy)
basr %r5,%r0
.Lmemcpy_base:
ltr %r4,%r4
bzr %r14
ahi %r4,-1
lr %r0,%r4
srl %r0,8
ltr %r0,%r0
lr %r1,%r2
jnz .Lmemcpy_loop
.Lmemcpy_rest:
ex %r4,.Lmemcpy_mvc-.Lmemcpy_base(%r5)
br %r14
.Lmemcpy_loop:
mvc 0(256,%r1),0(%r3)
la %r1,256(%r1)
la %r3,256(%r3)
brct %r0,.Lmemcpy_loop
j .Lmemcpy_rest
.Lmemcpy_mvc:
mvc 0(1,%r1),0(%r3)