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/* $NetBSD: memset.S,v 1.2 2013/03/17 02:12:41 christos Exp $ */
/*
* Copyright (c) 1996-2002 Eduardo Horvath
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include "strmacros.h"
#if defined(LIBC_SCCS) && !defined(lint)
RCSID("$NetBSD: memset.S,v 1.2 2013/03/17 02:12:41 christos Exp $")
#endif /* LIBC_SCCS and not lint */
/*
* XXXXXXXXXXXXXXXXXXXX
* We need to make sure that this doesn't use floating point
* before our trap handlers are installed or we could panic
* XXXXXXXXXXXXXXXXXXXX
*/
/*
* memset(addr, c, len)
*
* We want to use VIS instructions if we're clearing out more than
* 256 bytes, but to do that we need to properly save and restore the
* FP registers. Unfortunately the code to do that in the kernel needs
* to keep track of the current owner of the FPU, hence the different
* code.
*
* XXXXX To produce more efficient code, we do not allow lengths
* greater than 0x80000000000000000, which are negative numbers.
* This should not really be an issue since the VA hole should
* cause any such ranges to fail anyway.
*/
#if !defined(_KERNEL) || defined(_RUMPKERNEL)
ENTRY(bzero)
! %o0 = addr, %o1 = len
mov %o1, %o2
clr %o1 ! ser pattern
#endif
ENTRY(memset)
! %o0 = addr, %o1 = pattern, %o2 = len
mov %o0, %o4 ! Save original pointer
Lmemset_internal:
btst 7, %o0 ! Word aligned?
bz,pn %xcc, 0f
nop
inc %o0
deccc %o2 ! Store up to 7 bytes
bge,a,pt CCCR, Lmemset_internal
stb %o1, [%o0 - 1]
retl ! Duplicate Lmemset_done
mov %o4, %o0
0:
/*
* Duplicate the pattern so it fills 64-bits.
*/
andcc %o1, 0x0ff, %o1 ! No need to extend zero
bz,pt %icc, 1f
sllx %o1, 8, %o3 ! sigh. all dependent insns.
or %o1, %o3, %o1
sllx %o1, 16, %o3
or %o1, %o3, %o1
sllx %o1, 32, %o3
or %o1, %o3, %o1
1:
#ifdef USE_BLOCK_STORE_LOAD
!! Now we are 64-bit aligned
cmp %o2, 256 ! Use block clear if len > 256
bge,pt CCCR, Lmemset_block ! use block store insns
#endif /* USE_BLOCK_STORE_LOAD */
deccc 8, %o2
Lmemset_longs:
bl,pn CCCR, Lmemset_cleanup ! Less than 8 bytes left
nop
3:
inc 8, %o0
deccc 8, %o2
bge,pt CCCR, 3b
stx %o1, [%o0 - 8] ! Do 1 longword at a time
/*
* Len is in [-8..-1] where -8 => done, -7 => 1 byte to zero,
* -6 => two bytes, etc. Mop up this remainder, if any.
*/
Lmemset_cleanup:
btst 4, %o2
bz,pt CCCR, 5f ! if (len & 4) {
nop
stw %o1, [%o0] ! *(int *)addr = 0;
inc 4, %o0 ! addr += 4;
5:
btst 2, %o2
bz,pt CCCR, 7f ! if (len & 2) {
nop
sth %o1, [%o0] ! *(short *)addr = 0;
inc 2, %o0 ! addr += 2;
7:
btst 1, %o2
bnz,a %icc, Lmemset_done ! if (len & 1)
stb %o1, [%o0] ! *addr = 0;
Lmemset_done:
retl
mov %o4, %o0 ! Restore ponter for memset (ugh)
#ifdef USE_BLOCK_STORE_LOAD
Lmemset_block:
sethi %hi(block_disable), %o3
ldx [ %o3 + %lo(block_disable) ], %o3
brnz,pn %o3, Lmemset_longs
!! Make sure our trap table is installed
set _C_LABEL(trapbase), %o5
rdpr %tba, %o3
sub %o3, %o5, %o3
brnz,pn %o3, Lmemset_longs ! No, then don't use block load/store
nop
/*
* Kernel:
*
* Here we use VIS instructions to do a block clear of a page.
* But before we can do that we need to save and enable the FPU.
* The last owner of the FPU registers is fplwp, and
* fplwp->l_md.md_fpstate is the current fpstate. If that's not
* null, call savefpstate() with it to store our current fp state.
*
* Next, allocate an aligned fpstate on the stack. We will properly
* nest calls on a particular stack so this should not be a problem.
*
* Now we grab either curlwp (or if we're on the interrupt stack
* lwp0). We stash its existing fpstate in a local register and
* put our new fpstate in curlwp->p_md.md_fpstate. We point
* fplwp at curlwp (or lwp0) and enable the FPU.
*
* If we are ever preempted, our FPU state will be saved in our
* fpstate. Then, when we're resumed and we take an FPDISABLED
* trap, the trap handler will be able to fish our FPU state out
* of curlwp (or lwp0).
*
* On exiting this routine we undo the damage: restore the original
* pointer to curlwp->p_md.md_fpstate, clear our fplwp, and disable
* the MMU.
*
*/
ENABLE_FPU(0)
!! We are now 8-byte aligned. We need to become 64-byte aligned.
btst 63, %i0
bz,pt CCCR, 2f
nop
1:
stx %i1, [%i0]
inc 8, %i0
btst 63, %i0
bnz,pt %xcc, 1b
dec 8, %i2
2:
brz %i1, 3f ! Skip the memory op
fzero %f0 ! if pattern is 0
#ifdef _LP64
stx %i1, [%i0] ! Flush this puppy to RAM
membar #StoreLoad
ldd [%i0], %f0
#else
stw %i1, [%i0] ! Flush this puppy to RAM
membar #StoreLoad
ld [%i0], %f0
fmovsa %icc, %f0, %f1
#endif
3:
fmovd %f0, %f2 ! Duplicate the pattern
fmovd %f0, %f4
fmovd %f0, %f6
fmovd %f0, %f8
fmovd %f0, %f10
fmovd %f0, %f12
fmovd %f0, %f14
!! Remember: we were 8 bytes too far
dec 56, %i2 ! Go one iteration too far
5:
stda %f0, [%i0] ASI_STORE ! Store 64 bytes
deccc BLOCK_SIZE, %i2
bg,pt %icc, 5b
inc BLOCK_SIZE, %i0
membar #Sync
/*
* We've saved our possible fpstate, now disable the fpu
* and continue with life.
*/
RESTORE_FPU
addcc %i2, 56, %i2 ! Restore the count
ba,pt %xcc, Lmemset_longs ! Finish up the remainder
restore
#endif /* USE_BLOCK_STORE_LOAD */
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