linux/arch/xtensa/lib/memset.S
Chris Zankel 173d668138 [PATCH] xtensa: remove extra header files
The Xtensa port contained many header files that were never needed.  This
rather lengthy patch removes all those files.  Unfortunately, there were
many dependencies that needed to be updated, so this patch touches quite a
few source files.

Signed-off-by: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-12-10 09:55:39 -08:00

160 lines
3.8 KiB
ArmAsm

/*
* arch/xtensa/lib/memset.S
*
* ANSI C standard library function memset
* (Well, almost. .fixup code might return zero.)
*
* This file is subject to the terms and conditions of the GNU General
* Public License. See the file "COPYING" in the main directory of
* this archive for more details.
*
* Copyright (C) 2002 Tensilica Inc.
*/
#include <asm/variant/core.h>
/*
* void *memset(void *dst, int c, size_t length)
*
* The algorithm is as follows:
* Create a word with c in all byte positions
* If the destination is aligned,
* do 16B chucks with a loop, and then finish up with
* 8B, 4B, 2B, and 1B stores conditional on the length.
* If destination is unaligned, align it by conditionally
* setting 1B and 2B and then go to aligned case.
* This code tries to use fall-through branches for the common
* case of an aligned destination (except for the branches to
* the alignment labels).
*/
/* Load or store instructions that may cause exceptions use the EX macro. */
#define EX(insn,reg1,reg2,offset,handler) \
9: insn reg1, reg2, offset; \
.section __ex_table, "a"; \
.word 9b, handler; \
.previous
.text
.align 4
.global memset
.type memset,@function
memset:
entry sp, 16 # minimal stack frame
# a2/ dst, a3/ c, a4/ length
extui a3, a3, 0, 8 # mask to just 8 bits
slli a7, a3, 8 # duplicate character in all bytes of word
or a3, a3, a7 # ...
slli a7, a3, 16 # ...
or a3, a3, a7 # ...
mov a5, a2 # copy dst so that a2 is return value
movi a6, 3 # for alignment tests
bany a2, a6, .Ldstunaligned # if dst is unaligned
.L0: # return here from .Ldstunaligned when dst is aligned
srli a7, a4, 4 # number of loop iterations with 16B
# per iteration
bnez a4, .Laligned
retw
/*
* Destination is word-aligned.
*/
# set 16 bytes per iteration for word-aligned dst
.align 4 # 1 mod 4 alignment for LOOPNEZ
.byte 0 # (0 mod 4 alignment for LBEG)
.Laligned:
#if XCHAL_HAVE_LOOPS
loopnez a7, .Loop1done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .Loop1done
slli a6, a7, 4
add a6, a6, a5 # a6 = end of last 16B chunk
#endif /* !XCHAL_HAVE_LOOPS */
.Loop1:
EX(s32i, a3, a5, 0, memset_fixup)
EX(s32i, a3, a5, 4, memset_fixup)
EX(s32i, a3, a5, 8, memset_fixup)
EX(s32i, a3, a5, 12, memset_fixup)
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
blt a5, a6, .Loop1
#endif /* !XCHAL_HAVE_LOOPS */
.Loop1done:
bbci.l a4, 3, .L2
# set 8 bytes
EX(s32i, a3, a5, 0, memset_fixup)
EX(s32i, a3, a5, 4, memset_fixup)
addi a5, a5, 8
.L2:
bbci.l a4, 2, .L3
# set 4 bytes
EX(s32i, a3, a5, 0, memset_fixup)
addi a5, a5, 4
.L3:
bbci.l a4, 1, .L4
# set 2 bytes
EX(s16i, a3, a5, 0, memset_fixup)
addi a5, a5, 2
.L4:
bbci.l a4, 0, .L5
# set 1 byte
EX(s8i, a3, a5, 0, memset_fixup)
.L5:
.Lret1:
retw
/*
* Destination is unaligned
*/
.Ldstunaligned:
bltui a4, 8, .Lbyteset # do short copies byte by byte
bbci.l a5, 0, .L20 # branch if dst alignment half-aligned
# dst is only byte aligned
# set 1 byte
EX(s8i, a3, a5, 0, memset_fixup)
addi a5, a5, 1
addi a4, a4, -1
# now retest if dst aligned
bbci.l a5, 1, .L0 # if now aligned, return to main algorithm
.L20:
# dst half-aligned
# set 2 bytes
EX(s16i, a3, a5, 0, memset_fixup)
addi a5, a5, 2
addi a4, a4, -2
j .L0 # dst is now aligned, return to main algorithm
/*
* Byte by byte set
*/
.align 4
.byte 0 # 1 mod 4 alignment for LOOPNEZ
# (0 mod 4 alignment for LBEG)
.Lbyteset:
#if XCHAL_HAVE_LOOPS
loopnez a4, .Lbytesetdone
#else /* !XCHAL_HAVE_LOOPS */
beqz a4, .Lbytesetdone
add a6, a5, a4 # a6 = ending address
#endif /* !XCHAL_HAVE_LOOPS */
.Lbyteloop:
EX(s8i, a3, a5, 0, memset_fixup)
addi a5, a5, 1
#if !XCHAL_HAVE_LOOPS
blt a5, a6, .Lbyteloop
#endif /* !XCHAL_HAVE_LOOPS */
.Lbytesetdone:
retw
.section .fixup, "ax"
.align 4
/* We return zero if a failure occurred. */
memset_fixup:
movi a2, 0
retw