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/*
* Copyright (c) 2009
* MIPS Technologies, Inc., California.
*
* 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. Neither the name of the MIPS Technologies, Inc., 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 MIPS TECHNOLOGIES, INC. ``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 MIPS TECHNOLOGIES, INC. 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.
*/
/************************************************************************
*
* memset.S, version "64h" with 1 cache line horizon for "pref 30" and 14 nops
* Version: "043009"
*
************************************************************************/
/************************************************************************
* Include files
************************************************************************/
#include "machine/asm.h"
/*
* This routine could be optimized for MIPS64. The current code only
* uses MIPS32 instructions.
*/
#if defined(__MIPSEB__)
# define SWHI swl /* high part is left in big-endian */
#endif
#if defined(__MIPSEL__)
# define SWHI swr /* high part is right in little-endian */
#endif
#if !(defined(XGPROF) || defined(XPROF))
#undef SETUP_GP
#define SETUP_GP
#endif
LEAF(memset_cmips,0)
.set noreorder
.set noat
addu t0,a0,a2 # t0 is the "past the end" address
slti AT,a2,4 # is a2 less than 4?
bne AT,zero,.Llast4 # if yes, go to last4
move v0,a0 # memset returns the dst pointer
beq a1,zero,.Lset0
subu v1,zero,a0
# smear byte into 32 bit word
#if (__mips==32) && (__mips_isa_rev>=2)
ins a1, a1, 8, 8 # Replicate fill byte into half-word.
ins a1, a1, 16, 16 # Replicate fill byte into word.
#else
and a1,0xff
sll AT,a1,8
or a1,AT
sll AT,a1,16
or a1,AT
#endif
.Lset0: andi v1,v1,0x3 # word-unaligned address?
beq v1,zero,.Laligned # v1 is the unalignment count
subu a2,a2,v1
SWHI a1,0(a0)
addu a0,a0,v1
# Here we have the "word-aligned" a0 (until the "last4")
.Laligned:
andi t8,a2,0x3f # any 64-byte chunks?
# t8 is the byte count past 64-byte chunks
beq a2,t8,.Lchk8w # when a2==t8, no 64-byte chunks
# There will be at most 1 32-byte chunk then
subu a3,a2,t8 # subtract from a2 the reminder
# Here a3 counts bytes in 16w chunks
addu a3,a0,a3 # Now a3 is the final dst after 64-byte chunks
# Find out, if there are any 64-byte chunks after which will be still at least
# 96 bytes left. The value "96" is calculated as needed buffer for
# "pref 30,64(a0)" prefetch, which can be used as "pref 30,0(a0)" after
# incrementing "a0" by 64.
# For "a2" below 160 there will be no such "pref 30 safe" 64-byte chunk.
#
sltiu v1,a2,160
bgtz v1,.Lloop16w_nopref30 # skip "pref 30,0(a0)"
subu t7,a2,96 # subtract "pref 30 unsafe" region
# below we have at least 1 64-byte chunk which is "pref 30 safe"
andi t6,t7,0x3f # t6 is past "64-byte safe chunks" reminder
subu t5,t7,t6 # subtract from t7 the reminder
# Here t5 counts bytes in 16w "safe" chunks
addu t4,a0,t5 # Now t4 is the dst after 64-byte "safe" chunks
# Don't use "pref 30,0(a0)" for a0 in a "middle" of a cache line
# pref 30,0(a0)
# Here we are in the region, where it is safe to use "pref 30,64(a0)"
.Lloop16w:
addiu a0,a0,64
pref 30,-32(a0) # continue setting up the dest, addr 64-32
sw a1,-64(a0)
sw a1,-60(a0)
sw a1,-56(a0)
sw a1,-52(a0)
sw a1,-48(a0)
sw a1,-44(a0)
sw a1,-40(a0)
sw a1,-36(a0)
nop
nop # the extra nop instructions help to balance
nop # cycles needed for "store" + "fill" + "evict"
nop # For 64byte store there are needed 8 fill
nop # and 8 evict cycles, i.e. at least 32 instr.
nop
nop
pref 30,0(a0) # continue setting up the dest, addr 64-0
sw a1,-32(a0)
sw a1,-28(a0)
sw a1,-24(a0)
sw a1,-20(a0)
sw a1,-16(a0)
sw a1,-12(a0)
sw a1,-8(a0)
sw a1,-4(a0)
nop
nop
nop
nop # NOTE: adding 14 nop-s instead of 12 nop-s
nop # gives better results for "fast" memory
nop
bne a0,t4,.Lloop16w
nop
beq a0,a3,.Lchk8w # maybe no more 64-byte chunks?
nop # this "delayed slot" is useless ...
.Lloop16w_nopref30: # there could be up to 3 "64-byte nopref30" chunks
addiu a0,a0,64
sw a1,-64(a0)
sw a1,-60(a0)
sw a1,-56(a0)
sw a1,-52(a0)
sw a1,-48(a0)
sw a1,-44(a0)
sw a1,-40(a0)
sw a1,-36(a0)
sw a1,-32(a0)
sw a1,-28(a0)
sw a1,-24(a0)
sw a1,-20(a0)
sw a1,-16(a0)
sw a1,-12(a0)
sw a1,-8(a0)
bne a0,a3,.Lloop16w_nopref30
sw a1,-4(a0)
.Lchk8w: # t8 here is the byte count past 64-byte chunks
andi t7,t8,0x1f # is there a 32-byte chunk?
# the t7 is the reminder count past 32-bytes
beq t8,t7,.Lchk1w # when t8==t7, no 32-byte chunk
move a2,t7
sw a1,0(a0)
sw a1,4(a0)
sw a1,8(a0)
sw a1,12(a0)
sw a1,16(a0)
sw a1,20(a0)
sw a1,24(a0)
sw a1,28(a0)
addiu a0,a0,32
.Lchk1w:
andi t8,a2,0x3 # now t8 is the reminder past 1w chunks
beq a2,t8,.Llast4
subu a3,a2,t8 # a3 is the count of bytes in 1w chunks
addu a3,a0,a3 # now a3 is the dst address past the 1w chunks
# copying in words (4-byte chunks)
.LwordCopy_loop:
addiu a0,a0,4
bne a0,a3,.LwordCopy_loop
sw a1,-4(a0)
.Llast4:beq a0,t0,.Llast4e
.Llast4l:addiu a0,a0,1
bne a0,t0,.Llast4l
sb a1,-1(a0)
.Llast4e:
j ra
nop
.set at
.set reorder
END(memset_cmips)
/************************************************************************
* Implementation : Static functions
************************************************************************/
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