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+ # Optimized memset implementation for PowerPC.
+ # Copyright (C) 1997 Free Software Foundation, Inc.
+ # This file is part of the GNU C Library.
+ #
+ # The GNU C Library is free software; you can redistribute it and/or
+ # modify it under the terms of the GNU Library General Public License as
+ # published by the Free Software Foundation; either version 2 of the
+ # License, or (at your option) any later version.
+ #
+ # The GNU C Library is distributed in the hope that it will be useful,
+ # but WITHOUT ANY WARRANTY; without even the implied warranty of
+ # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ # Library General Public License for more details.
+ #
+ # You should have received a copy of the GNU Library General Public
+ # License along with the GNU C Library; see the file COPYING.LIB. If not,
+ # write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ # Boston, MA 02111-1307, USA.
+
+ .section ".text"
+ .align 5
+ nop
+
+ .globl memset
+ .type memset,@function
+memset:
+ # __ptr_t [r3] memset (__ptr_t s [r3], int c [r4], size_t n [r5]));
+ # Returns 's'.
+
+ # The memset is done in three sizes: byte (8 bits), word (32 bits),
+ # cache line (256 bits). There is a special case for setting cache lines
+ # to 0, to take advantage of the dcbz instruction.
+ # r6: current address we are storing at
+ # r7: number of bytes we are setting now (when aligning)
+
+ # take care of case for size <= 4
+ cmplwi %cr1,%r5,4
+ andi. %r7,%r3,3
+ mr %r6,%r3
+ ble- %cr1,small
+ # align to word boundary
+ cmplwi %cr5,%r5,31
+ rlwimi %r4,%r4,8,16,23
+ beq+ aligned # 8th instruction from .align
+ mtcrf 0x01,%r3
+ subfic %r7,%r7,4
+ add %r6,%r6,%r7
+ sub %r5,%r5,%r7
+ bf+ 31,0f
+ stb %r4,0(%r3)
+ bt 30,aligned
+0: sth %r4,-2(%r6) # 16th instruction from .align
+ # take care of case for size < 31
+aligned:
+ mtcrf 0x01,%r5
+ rlwimi %r4,%r4,16,0,15
+ ble %cr5,medium
+ # align to cache line boundary...
+ andi. %r7,%r6,0x1C
+ subfic %r7,%r7,0x20
+ beq caligned
+ mtcrf 0x01,%r7
+ add %r6,%r6,%r7
+ sub %r5,%r5,%r7
+ cmplwi %cr1,%r7,0x10
+ mr %r8,%r6
+ bf 28,1f
+ stw %r4,-4(%r8)
+ stwu %r4,-8(%r8)
+1: blt %cr1,2f
+ stw %r4,-4(%r8) # 32nd instruction from .align
+ stw %r4,-8(%r8)
+ stw %r4,-12(%r8)
+ stwu %r4,-16(%r8)
+2: bf 29,caligned
+ stw %r4,-4(%r8)
+ # now aligned to a cache line.
+caligned:
+ cmplwi %cr1,%r4,0
+ clrrwi. %r7,%r5,5
+ mtcrf 0x01,%r5 # 40th instruction from .align
+ beq %cr1,zloopstart # special case for clearing memory using dcbz
+ srwi %r0,%r7,5
+ mtctr %r0
+ beq medium # we may not actually get to do a full line
+ clrlwi. %r5,%r5,27
+ add %r6,%r6,%r7
+0: li %r8,-0x40
+ bdz cloopdone # 48th instruction from .align
+
+cloop: dcbz %r8,%r6
+ stw %r4,-4(%r6)
+ stw %r4,-8(%r6)
+ stw %r4,-12(%r6)
+ stw %r4,-16(%r6)
+ nop # let 601 fetch last 4 instructions of loop
+ stw %r4,-20(%r6)
+ stw %r4,-24(%r6) # 56th instruction from .align
+ nop # let 601 fetch first 8 instructions of loop
+ stw %r4,-28(%r6)
+ stwu %r4,-32(%r6)
+ bdnz cloop
+cloopdone:
+ stw %r4,-4(%r6)
+ stw %r4,-8(%r6)
+ stw %r4,-12(%r6)
+ stw %r4,-16(%r6) # 64th instruction from .align
+ stw %r4,-20(%r6)
+ cmplwi %cr1,%r5,16
+ stw %r4,-24(%r6)
+ stw %r4,-28(%r6)
+ stwu %r4,-32(%r6)
+ beqlr
+ add %r6,%r6,%r7
+ b medium_tail2 # 72nd instruction from .align
+
+ .align 5
+ nop
+# clear lines of memory in 128-byte chunks.
+zloopstart:
+ clrlwi %r5,%r5,27
+ mtcrf 0x02,%r7
+ srwi. %r0,%r7,7
+ mtctr %r0
+ li %r7,0x20
+ li %r8,-0x40
+ cmplwi %cr1,%r5,16 # 8
+ bf 26,0f
+ dcbz 0,%r6
+ addi %r6,%r6,0x20
+0: li %r9,-0x20
+ bf 25,1f
+ dcbz 0,%r6
+ dcbz %r7,%r6
+ addi %r6,%r6,0x40 # 16
+1: cmplwi %cr5,%r5,0
+ beq medium
+zloop:
+ dcbz 0,%r6
+ dcbz %r7,%r6
+ addi %r6,%r6,0x80
+ dcbz %r8,%r6
+ dcbz %r9,%r6
+ bdnz zloop
+ beqlr %cr5
+ b medium_tail2
+
+ .align 5
+small:
+ # Memset of 4 bytes or less.
+ cmplwi %cr5,%r5,1
+ cmplwi %cr1,%r5,3
+ bltlr %cr5
+ stb %r4,0(%r6)
+ beqlr %cr5
+ nop
+ stb %r4,1(%r6)
+ bltlr %cr1
+ stb %r4,2(%r6)
+ beqlr %cr1
+ nop
+ stb %r4,3(%r6)
+ blr
+
+# memset of 0-31 bytes
+ .align 5
+medium:
+ cmplwi %cr1,%r5,16
+medium_tail2:
+ add %r6,%r6,%r5
+medium_tail:
+ bt- 31,medium_31t
+ bt- 30,medium_30t
+medium_30f:
+ bt- 29,medium_29t
+medium_29f:
+ bge- %cr1,medium_27t
+ bflr- 28
+ stw %r4,-4(%r6) # 8th instruction from .align
+ stw %r4,-8(%r6)
+ blr
+
+medium_31t:
+ stbu %r4,-1(%r6)
+ bf- 30,medium_30f
+medium_30t:
+ sthu %r4,-2(%r6)
+ bf- 29,medium_29f
+medium_29t:
+ stwu %r4,-4(%r6)
+ blt- %cr1,medium_27f # 16th instruction from .align
+medium_27t:
+ stw %r4,-4(%r6)
+ stw %r4,-8(%r6)
+ stw %r4,-12(%r6)
+ stwu %r4,-16(%r6)
+medium_27f:
+ bflr- 28
+medium_28t:
+ stw %r4,-4(%r6)
+ stw %r4,-8(%r6)
+ blr