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/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
*/
.file "memset.s"
/*
* char *memset(sp, c, n)
*
* Set an array of n chars starting at sp to the character c.
* Return sp.
*
* Fast assembler language version of the following C-program for memset
* which represents the `standard' for the C-library.
*
* void *
* memset(void *sp1, int c, size_t n)
* {
* if (n != 0) {
* char *sp = sp1;
* do {
* *sp++ = (char)c;
* } while (--n != 0);
* }
* return (sp1);
* }
*
* Flow :
*
* For small 6 or fewer bytes stores, bytes will be stored.
*
* For less than 32 bytes stores, align the address on 4 byte boundary.
* Then store as many 4-byte chunks, followed by trailing bytes.
*
* For sizes greater than 32 bytes, align the address on 8 byte boundary.
* if (count > 64) {
* store as many 8-bytes chunks to block align the address
* store using ASI_BLK_INIT_ST_QUAD_LDD_P
* }
* Store as many 8-byte chunks, followed by trialing bytes.
*
*/
#include <sys/asm_linkage.h>
#include <sys/niagaraasi.h>
#include <sys/asi.h>
ANSI_PRAGMA_WEAK(memset,function)
.section ".text"
.align 32
ENTRY(memset)
mov %o0, %o5 ! copy sp1 before using it
cmp %o2, 7 ! if small counts, just write bytes
blu,pn %ncc, .wrchar
and %o1, 0xff, %o1 ! o1 is (char)c
sll %o1, 8, %o3
or %o1, %o3, %o1 ! now o1 has 2 bytes of c
sll %o1, 16, %o3
cmp %o2, 0x20
blu,pn %ncc, .wdalign
or %o1, %o3, %o1 ! now o1 has 4 bytes of c
sllx %o1, 32, %o3
or %o1, %o3, %o1 ! now o1 has 8 bytes of c
.dbalign:
andcc %o5, 7, %o3 ! is sp1 aligned on a 8 byte bound
bz,pt %ncc, .blkalign ! already double aligned
sub %o3, 8, %o3 ! -(bytes till double aligned)
add %o2, %o3, %o2 ! update o2 with new count
! Set -(%o3) bytes till sp1 double aligned
1: stb %o1, [%o5] ! there is at least 1 byte to set
inccc %o3 ! byte clearing loop
bl,pt %ncc, 1b
inc %o5
! Now sp1 is double aligned (sp1 is found in %o5)
.blkalign:
mov ASI_BLK_INIT_ST_QUAD_LDD_P, %asi
cmp %o2, 0x40 ! check if there are 64 bytes to set
blu,pn %ncc, 5f
mov %o2, %o3
andcc %o5, 63, %o3 ! is sp1 block aligned?
bz,pt %ncc, .blkwr ! now block aligned
sub %o3, 64, %o3 ! o3 is -(bytes till block aligned)
add %o2, %o3, %o2 ! o2 is the remainder
! Store -(%o3) bytes till dst is block (64 byte) aligned.
! Use double word stores.
! Recall that dst is already double word aligned
1:
stx %o1, [%o5]
addcc %o3, 8, %o3
bl,pt %ncc, 1b
add %o5, 8, %o5
! Now sp1 is block aligned
.blkwr:
and %o2, 63, %o3 ! calc bytes left after blk store.
andn %o2, 63, %o4 ! calc size of blocks in bytes
cmp %o4, 0x100 ! check if there are 256 bytes to set
blu,pn %ncc, 3f
nop
2:
stxa %o1, [%o5+0x0]%asi
stxa %o1, [%o5+0x40]%asi
stxa %o1, [%o5+0x80]%asi
stxa %o1, [%o5+0xc0]%asi
stxa %o1, [%o5+0x8]%asi
stxa %o1, [%o5+0x10]%asi
stxa %o1, [%o5+0x18]%asi
stxa %o1, [%o5+0x20]%asi
stxa %o1, [%o5+0x28]%asi
stxa %o1, [%o5+0x30]%asi
stxa %o1, [%o5+0x38]%asi
stxa %o1, [%o5+0x48]%asi
stxa %o1, [%o5+0x50]%asi
stxa %o1, [%o5+0x58]%asi
stxa %o1, [%o5+0x60]%asi
stxa %o1, [%o5+0x68]%asi
stxa %o1, [%o5+0x70]%asi
stxa %o1, [%o5+0x78]%asi
stxa %o1, [%o5+0x88]%asi
stxa %o1, [%o5+0x90]%asi
stxa %o1, [%o5+0x98]%asi
stxa %o1, [%o5+0xa0]%asi
stxa %o1, [%o5+0xa8]%asi
stxa %o1, [%o5+0xb0]%asi
stxa %o1, [%o5+0xb8]%asi
stxa %o1, [%o5+0xc8]%asi
stxa %o1, [%o5+0xd0]%asi
stxa %o1, [%o5+0xd8]%asi
stxa %o1, [%o5+0xe0]%asi
stxa %o1, [%o5+0xe8]%asi
stxa %o1, [%o5+0xf0]%asi
stxa %o1, [%o5+0xf8]%asi
sub %o4, 0x100, %o4
cmp %o4, 0x100
bgu,pt %ncc, 2b
add %o5, 0x100, %o5
3:
cmp %o4, 0x40 ! check if 64 bytes to set
blu %ncc, 5f
nop
4:
stxa %o1, [%o5+0x0]%asi
stxa %o1, [%o5+0x8]%asi
stxa %o1, [%o5+0x10]%asi
stxa %o1, [%o5+0x18]%asi
stxa %o1, [%o5+0x20]%asi
stxa %o1, [%o5+0x28]%asi
stxa %o1, [%o5+0x30]%asi
stxa %o1, [%o5+0x38]%asi
subcc %o4, 0x40, %o4
bgu,pt %ncc, 4b
add %o5, 0x40, %o5
5:
! Set the remaining doubles
membar #Sync
mov ASI_PNF, %asi ! restore %asi to default
! ASI_PRIMARY_NOFAULT value
subcc %o3, 8, %o3 ! Can we store any doubles?
blu,pn %ncc, .wrchar
and %o2, 7, %o2 ! calc bytes left after doubles
6:
stx %o1, [%o5] ! store the doubles
subcc %o3, 8, %o3
bgeu,pt %ncc, 6b
add %o5, 8, %o5
ba .wrchar
nop
.wdalign:
andcc %o5, 3, %o3 ! is sp1 aligned on a word boundary
bz,pn %ncc, .wrword
andn %o2, 3, %o3 ! create word sized count in %o3
dec %o2 ! decrement count
stb %o1, [%o5] ! clear a byte
b .wdalign
inc %o5 ! next byte
.wrword:
st %o1, [%o5] ! 4-byte writing loop
subcc %o3, 4, %o3
bnz,pt %ncc, .wrword
inc 4, %o5
and %o2, 3, %o2 ! leftover count, if any
.wrchar:
! Set the remaining bytes, if any
cmp %o2, 0
be %ncc, .exit
nop
7:
deccc %o2
stb %o1, [%o5]
bgu,pt %ncc, 7b
inc %o5
.exit:
retl ! %o0 was preserved
nop
SET_SIZE(memset)
|
