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phys_memset improvements

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. verify length argument
	. use rep stosl / stosb
This commit is contained in:
Arne Welzel 2012-09-21 14:15:44 +02:00 committed by Ben Gras
parent 8a3b6ca3bb
commit 629829e69c
1 changed files with 14 additions and 28 deletions
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42
kernel/arch/i386/klib.S
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@ -316,49 +316,35 @@ ENTRY(__user_copy_msg_pointer_failure)
/* phys_memset */
/*===========================================================================*/
/*
* PUBLIC void phys_memset(phys_bytes source, unsigned long pattern,
* PUBLIC void phys_memset(phys_bytes dst, unsigned long pattern,
* phys_bytes bytecount);
* Fill a block of physical memory with pattern.
*/
ENTRY(phys_memset)
push %ebp
mov %esp, %ebp
push %esi
push %ebx
push %edi
cld
mov 8(%ebp), %edi
mov 16(%ebp), %ecx
mov 12(%ebp), %eax
shr $2, %ecx
rep stosl
mov 8(%ebp), %esi
mov 16(%ebp), %eax
mov 12(%ebp), %ebx
shr $2, %eax
fill_start:
mov %ebx, (%esi)
add $4, %esi
dec %eax
jne fill_start
/* Any remaining bytes? */
mov 16(%ebp), %eax
and $3, %eax
remain_fill:
cmp $0, %eax
je fill_done
movb 12(%ebp), %bl
movb %bl, (%esi)
add $1, %esi
inc %ebp
dec %eax
jmp remain_fill
mov 16(%ebp), %ecx
and $3, %ecx
rep stosb
fill_done:
LABEL(memset_fault) /* kernel can send us here */
mov $0, %eax /* 0 means: no fault */
pop %ebx
pop %esi
pop %edi
pop %ebp
ret
LABEL(memset_fault_in_kernel) /* kernel can send us here */
pop %ebx
pop %esi
pop %edi
pop %ebp
mov %cr2, %eax
ret