Substitute Mach 3.0 kernel bcopy() which is unrolled for aligned copies.
This commit is contained in:
jonathan
parent
f8f304c76c
commit
cbb2b5d0fb
@ -1,145 +1,198 @@
|
||||
/* $NetBSD: bcopy.S,v 1.5 1996/09/17 01:32:32 jonathan Exp $ */
|
||||
/* $NetBSD: bcopy.S,v 1.6 1997/08/09 02:02:08 jonathan Exp $ */
|
||||
|
||||
/*-
|
||||
* Copyright (c) 1991, 1993
|
||||
* The Regents of the University of California. All rights reserved.
|
||||
*
|
||||
* This code is derived from software contributed to Berkeley by
|
||||
* Ralph Campbell.
|
||||
*
|
||||
* 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.
|
||||
* 2. Redistributions in binary form must reproduce the above copyright
|
||||
* notice, this list of conditions and the following disclaimer in the
|
||||
* documentation and/or other materials provided with the distribution.
|
||||
* 3. All advertising materials mentioning features or use of this software
|
||||
* must display the following acknowledgement:
|
||||
* This product includes software developed by the University of
|
||||
* California, Berkeley and its contributors.
|
||||
* 4. Neither the name of the University nor the names of its contributors
|
||||
* may be used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
|
||||
*
|
||||
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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.
|
||||
/*
|
||||
* Mach Operating System
|
||||
* Copyright (c) 1993 Carnegie Mellon University
|
||||
* All Rights Reserved.
|
||||
*
|
||||
* Permission to use, copy, modify and distribute this software and its
|
||||
* documentation is hereby granted, provided that both the copyright
|
||||
* notice and this permission notice appear in all copies of the
|
||||
* software, derivative works or modified versions, and any portions
|
||||
* thereof, and that both notices appear in supporting documentation.
|
||||
*
|
||||
* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
|
||||
* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
|
||||
* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
|
||||
*
|
||||
* Carnegie Mellon requests users of this software to return to
|
||||
*
|
||||
* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
|
||||
* School of Computer Science
|
||||
* Carnegie Mellon University
|
||||
* Pittsburgh PA 15213-3890
|
||||
*
|
||||
* any improvements or extensions that they make and grant Carnegie Mellon
|
||||
* the rights to redistribute these changes.
|
||||
*/
|
||||
|
||||
/*
|
||||
* File: mips_bcopy.s
|
||||
* Author: Chris Maeda
|
||||
* Date: June 1993
|
||||
*
|
||||
* Fast copy routine. Derived from aligned_block_copy.
|
||||
*/
|
||||
|
||||
|
||||
#include <mips/asm.h>
|
||||
|
||||
#if defined(LIBC_SCCS) && !defined(lint)
|
||||
ASMSTR("from: @(#)bcopy.s 8.1 (Berkeley) 6/4/93")
|
||||
ASMSTR("$NetBSD: bcopy.S,v 1.5 1996/09/17 01:32:32 jonathan Exp $")
|
||||
ASMSTR("from: @(#)mips_bcopy.s 2.2 CMU 18/06/93")
|
||||
ASMSTR("$NetBSD: bcopy.S,v 1.6 1997/08/09 02:02:08 jonathan Exp $")
|
||||
#endif /* LIBC_SCCS and not lint */
|
||||
|
||||
#ifdef ABICALLS
|
||||
.abicalls
|
||||
#endif
|
||||
|
||||
/* bcopy(s1, s2, n) */
|
||||
|
||||
#ifdef MIPSEL
|
||||
# define LWHI lwr
|
||||
# define LWLO lwl
|
||||
# define SWHI swr
|
||||
# define SWLO swl
|
||||
#endif
|
||||
#ifdef MIPSEB
|
||||
# define LWHI lwl
|
||||
# define LWLO lwr
|
||||
# define SWHI swl
|
||||
# define SWLO swr
|
||||
#endif
|
||||
/*
|
||||
* bcopy(caddr_t src, caddr_t dst, unsigned int len)
|
||||
*
|
||||
* a0 src address
|
||||
* a1 dst address
|
||||
* a2 length
|
||||
*/
|
||||
|
||||
LEAF(bcopy)
|
||||
.set noat
|
||||
.set noreorder
|
||||
addu t0, a0, a2 # t0 = end of s1 region
|
||||
sltu t1, a1, t0
|
||||
sltu t2, a0, a1
|
||||
and t1, t1, t2 # t1 = true if from < to < (from+len)
|
||||
beq t1, zero, forward # non overlapping, do forward copy
|
||||
slt t2, a2, 12 # check for small copy
|
||||
/*
|
||||
* Make sure we can copy forwards.
|
||||
*/
|
||||
sltu t0,a0,a1 # t0 == a0 < a1
|
||||
addu a3,a0,a2 # a3 == end of source
|
||||
sltu t1,a1,a3 # t1 == a1 < a0+a2
|
||||
and t2,t0,t1 # overlap -- copy backwards
|
||||
bne t2,zero,backcopy
|
||||
|
||||
ble a2, zero, 2f
|
||||
addu t1, a1, a2 # t1 = end of to region
|
||||
/*
|
||||
* There are four alignment cases (with frequency)
|
||||
* (Based on measurements taken with a DECstation 5000/200
|
||||
* inside a Mach kernel.)
|
||||
*
|
||||
* aligned -> aligned (mostly)
|
||||
* unaligned -> aligned (sometimes)
|
||||
* aligned,unaligned -> unaligned (almost never)
|
||||
*
|
||||
* Note that we could add another case that checks if
|
||||
* the destination and source are unaligned but the
|
||||
* copy is alignable. eg if src and dest are both
|
||||
* on a halfword boundary.
|
||||
*/
|
||||
andi t1,a1,3 # get last 3 bits of dest
|
||||
bne t1,zero,bytecopy
|
||||
andi t0,a0,3 # get last 3 bits of src
|
||||
bne t0,zero,destaligned
|
||||
|
||||
/*
|
||||
* Forward aligned->aligned copy, 8*4 bytes at a time.
|
||||
*/
|
||||
li AT,-32
|
||||
and t0,a2,AT /* count truncated to multiple of 32 */
|
||||
addu a3,a0,t0 /* run fast loop up to this address */
|
||||
sltu AT,a0,a3 /* any work to do? */
|
||||
beq AT,zero,wordcopy
|
||||
subu a2,t0
|
||||
|
||||
/*
|
||||
* loop body
|
||||
*/
|
||||
cp:
|
||||
lw v0,0(a0)
|
||||
lw v1,4(a0)
|
||||
lw t0,8(a0)
|
||||
lw t1,12(a0)
|
||||
addu a0,32
|
||||
sw v0,0(a1)
|
||||
sw v1,4(a1)
|
||||
sw t0,8(a1)
|
||||
sw t1,12(a1)
|
||||
lw t1,-4(a0)
|
||||
lw t0,-8(a0)
|
||||
lw v1,-12(a0)
|
||||
lw v0,-16(a0)
|
||||
addu a1,32
|
||||
sw t1,-4(a1)
|
||||
sw t0,-8(a1)
|
||||
sw v1,-12(a1)
|
||||
bne a0,a3,cp
|
||||
sw v0,-16(a1)
|
||||
|
||||
/*
|
||||
* Copy a word at a time, no loop unrolling.
|
||||
*/
|
||||
wordcopy:
|
||||
andi t2,a2,3 # get byte count / 4
|
||||
subu t2,a2,t2 # t2 = number of words to copy * 4
|
||||
beq t2,zero,bytecopy
|
||||
addu t0,a0,t2 # stop at t0
|
||||
subu a2,a2,t2
|
||||
1:
|
||||
lb v0, -1(t0) # copy bytes backwards,
|
||||
subu t0, t0, 1 # doesnt happen often so do slow way
|
||||
subu t1, t1, 1
|
||||
bne t0, a0, 1b
|
||||
sb v0, 0(t1)
|
||||
lw v0,0(a0)
|
||||
addu a0,4
|
||||
sw v0,0(a1)
|
||||
bne a0,t0,1b
|
||||
addu a1,4
|
||||
|
||||
bytecopy:
|
||||
beq a2,zero,copydone # nothing left to do?
|
||||
nop
|
||||
2:
|
||||
lb v0,0(a0)
|
||||
addu a0,1
|
||||
sb v0,0(a1)
|
||||
subu a2,1
|
||||
bgtz a2,2b
|
||||
addu a1,1
|
||||
|
||||
copydone:
|
||||
j ra
|
||||
nop
|
||||
forward:
|
||||
bne t2, zero, smallcpy # do a small bcopy
|
||||
xor v0, a0, a1 # compare low two bits of addresses
|
||||
and v0, v0, 3
|
||||
subu a3, zero, a1 # compute # bytes to word align address
|
||||
beq v0, zero, aligned # addresses can be word aligned
|
||||
and a3, a3, 3
|
||||
|
||||
beq a3, zero, 1f
|
||||
subu a2, a2, a3 # subtract from remaining count
|
||||
LWHI v0, 0(a0) # get next 4 bytes (unaligned)
|
||||
LWLO v0, 3(a0)
|
||||
addu a0, a0, a3
|
||||
SWHI v0, 0(a1) # store 1, 2, or 3 bytes to align a1
|
||||
addu a1, a1, a3
|
||||
1:
|
||||
and v0, a2, 3 # compute number of words left
|
||||
subu a3, a2, v0
|
||||
move a2, v0
|
||||
addu a3, a3, a0 # compute ending address
|
||||
2:
|
||||
LWHI v0, 0(a0) # copy words a0 unaligned, a1 aligned
|
||||
LWLO v0, 3(a0)
|
||||
addu a0, a0, 4
|
||||
addu a1, a1, 4
|
||||
bne a0, a3, 2b
|
||||
sw v0, -4(a1)
|
||||
b smallcpy
|
||||
/*
|
||||
* Copy from unaligned source to aligned dest.
|
||||
*/
|
||||
destaligned:
|
||||
andi t0,a2,3 # t0 = bytecount mod 4
|
||||
subu a3,a2,t0 # number of words to transfer
|
||||
beq a3,zero,bytecopy
|
||||
nop
|
||||
aligned:
|
||||
beq a3, zero, 1f
|
||||
subu a2, a2, a3 # subtract from remaining count
|
||||
LWHI v0, 0(a0) # copy 1, 2, or 3 bytes to align
|
||||
addu a0, a0, a3
|
||||
SWHI v0, 0(a1)
|
||||
addu a1, a1, a3
|
||||
1:
|
||||
and v0, a2, 3 # compute number of whole words left
|
||||
subu a3, a2, v0
|
||||
move a2, v0
|
||||
addu a3, a3, a0 # compute ending address
|
||||
2:
|
||||
lw v0, 0(a0) # copy words
|
||||
addu a0, a0, 4
|
||||
addu a1, a1, 4
|
||||
bne a0, a3, 2b
|
||||
sw v0, -4(a1)
|
||||
smallcpy:
|
||||
ble a2, zero, 2f
|
||||
addu a3, a2, a0 # compute ending address
|
||||
1:
|
||||
lbu v0, 0(a0) # copy bytes
|
||||
addu a0, a0, 1
|
||||
addu a1, a1, 1
|
||||
bne a0, a3, 1b
|
||||
sb v0, -1(a1)
|
||||
2:
|
||||
move a2,t0 # this many to do after we are done
|
||||
addu a3,a0,a3 # stop point
|
||||
|
||||
3:
|
||||
#if MIPSEL /* little-endian */
|
||||
lwr v0,0(a0)
|
||||
lwl v0,3(a0)
|
||||
#else /* big-endian */
|
||||
lwl v0,0(a0)
|
||||
lwr v0,3(a0)
|
||||
#endif
|
||||
addi a0,4
|
||||
sw v0,0(a1)
|
||||
bne a0,a3,3b
|
||||
addi a1,4
|
||||
|
||||
j bytecopy
|
||||
nop
|
||||
|
||||
/*
|
||||
* Copy by bytes backwards.
|
||||
*/
|
||||
backcopy:
|
||||
blez a2,copydone # nothing left to do?
|
||||
addu t0,a0,a2 # end of source
|
||||
addu t1,a1,a2 # end of destination
|
||||
4:
|
||||
lb v0,-1(t0)
|
||||
subu t0,1
|
||||
sb v0,-1(t1)
|
||||
bne t0,a0,4b
|
||||
subu t1,1
|
||||
j ra
|
||||
nop
|
||||
|
||||
.set reorder
|
||||
END(bcopy)
|
||||
.set at
|
||||
END(bcopy)
|
||||
|
||||
Loading…
Reference in New Issue
Block a user