nuttx/libs/libc/machine/xtensa/arch_strcpy.S
zhuyanlin cfcff5f570 libc:machine:xtensa:add xtensa libc implement
N/A

Signed-off-by: zhuyanlin <zhuyanlin1@xiaomi.com>
2021-11-06 07:39:27 -05:00

244 lines
6.3 KiB
ArmAsm

/****************************************************************************
* libs/libc/machine/xtensa/arch_strcpy.S
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include "xtensa_asm.h"
#include <arch/chip/core-isa.h>
#include <arch/xtensa/xtensa_abi.h>
/****************************************************************************
* Public Functions
****************************************************************************/
.section .text
.begin schedule
.align 4
.literal_position
.global strcpy
.type strcpy, @function
strcpy:
ENTRY(16)
/* a2 = dst, a3 = src */
mov a10, a2 # leave dst in return value register
movi a4, MASK0
movi a5, MASK1
movi a6, MASK2
movi a7, MASK3
bbsi.l a3, 0, .Lsrc1mod2
bbsi.l a3, 1, .Lsrc2mod4
.Lsrcaligned:
/* Check if the destination is aligned. */
movi a8, 3
bnone a10, a8, .Laligned
j .Ldstunaligned
.Lsrc1mod2: # src address is odd
l8ui a8, a3, 0 # get byte 0
addi a3, a3, 1 # advance src pointer
s8i a8, a10, 0 # store byte 0
beqz a8, 1f # if byte 0 is zero
addi a10, a10, 1 # advance dst pointer
bbci.l a3, 1, .Lsrcaligned # if src is now word-aligned
.Lsrc2mod4: # src address is 2 mod 4
l8ui a8, a3, 0 # get byte 0
/* 1-cycle interlock */
s8i a8, a10, 0 # store byte 0
beqz a8, 1f # if byte 0 is zero
l8ui a8, a3, 1 # get byte 0
addi a3, a3, 2 # advance src pointer
s8i a8, a10, 1 # store byte 0
addi a10, a10, 2 # advance dst pointer
bnez a8, .Lsrcaligned
1: RET(16)
/* dst is word-aligned; src is word-aligned. */
.align 4
#if XCHAL_HAVE_LOOPS
#if XCHAL_HAVE_DENSITY
/* (2 mod 4) alignment for loop instruction */
#else
/* (1 mod 4) alignment for loop instruction */
.byte 0
.byte 0
#endif
.Laligned:
#if XCHAL_HAVE_DENSITY
_movi.n a8, 0 # set up for the maximum loop count
#else
_movi a8, 0 # set up for the maximum loop count
#endif
loop a8, .Lz3 # loop forever (almost anyway)
l32i a8, a3, 0 # get word from src
addi a3, a3, 4 # advance src pointer
bnone a8, a4, .Lz0 # if byte 0 is zero
bnone a8, a5, .Lz1 # if byte 1 is zero
bnone a8, a6, .Lz2 # if byte 2 is zero
s32i a8, a10, 0 # store word to dst
bnone a8, a7, .Lz3 # if byte 3 is zero
addi a10, a10, 4 # advance dst pointer
#else /* !XCHAL_HAVE_LOOPS */
1: addi a10, a10, 4 # advance dst pointer
.Laligned:
l32i a8, a3, 0 # get word from src
addi a3, a3, 4 # advance src pointer
bnone a8, a4, .Lz0 # if byte 0 is zero
bnone a8, a5, .Lz1 # if byte 1 is zero
bnone a8, a6, .Lz2 # if byte 2 is zero
s32i a8, a10, 0 # store word to dst
bany a8, a7, 1b # if byte 3 is zero
#endif /* !XCHAL_HAVE_LOOPS */
.Lz3: /* Byte 3 is zero. */
RET(16)
.Lz0: /* Byte 0 is zero. */
#if XCHAL_HAVE_BE
movi a8, 0
#endif
s8i a8, a10, 0
RET(16)
.Lz1: /* Byte 1 is zero. */
#if XCHAL_HAVE_BE
extui a8, a8, 16, 16
#endif
s16i a8, a10, 0
RET(16)
.Lz2: /* Byte 2 is zero. */
#if XCHAL_HAVE_BE
extui a8, a8, 16, 16
#endif
s16i a8, a10, 0
movi a8, 0
s8i a8, a10, 2
RET(16)
#if 1
/* For now just use byte copy loop for the unaligned destination case. */
.align 4
#if XCHAL_HAVE_LOOPS
#if XCHAL_HAVE_DENSITY
/* (2 mod 4) alignment for loop instruction */
#else
/* (1 mod 4) alignment for loop instruction */
.byte 0
.byte 0
#endif
#endif
.Ldstunaligned:
#if XCHAL_HAVE_LOOPS
#if XCHAL_HAVE_DENSITY
_movi.n a8, 0 # set up for the maximum loop count
#else
_movi a8, 0 # set up for the maximum loop count
#endif
loop a8, 2f # loop forever (almost anyway)
#endif
1: l8ui a8, a3, 0
addi a3, a3, 1
s8i a8, a10, 0
addi a10, a10, 1
#if XCHAL_HAVE_LOOPS
beqz a8, 2f
#else
bnez a8, 1b
#endif
2: RET(16)
#else /* 0 */
/* This code is not functional yet. */
.Ldstunaligned:
l32i a9, a2, 0 # load word from dst
#if XCHAL_HAVE_BE
ssa8b a9 # rotate by dst alignment so that
src a9, a9, a9 # shift in loop will put back in place
ssa8l a9 # shift left by byte*8
#else
ssa8l a9 # rotate by dst alignment so that
src a9, a9, a9 # shift in loop will put back in place
ssa8b a9 # shift left by 32-byte*8
#endif
/* dst is word-aligned; src is unaligned. */
.Ldstunalignedloop:
l32i a8, a3, 0 # get word from src
/* 1-cycle interlock */
bnone a8, a4, .Lu0 # if byte 0 is zero
bnone a8, a5, .Lu1 # if byte 1 is zero
bnone a8, a6, .Lu2 # if byte 2 is zero
src a9, a8, a9 # combine last word and this word
s32i a9, a10, 0 # store word to dst
bnone a8, a7, .Lu3 # if byte 3 is nonzero, iterate
l32i a9, a3, 4 # get word from src
addi a3, a3, 8 # advance src pointer
bnone a9, a4, .Lu4 # if byte 0 is zero
bnone a9, a5, .Lu5 # if byte 1 is zero
bnone a9, a6, .Lu6 # if byte 2 is zero
src a8, a9, a8 # combine last word and this word
s32i a8, a10, 4 # store word to dst
addi a10, a10, 8 # advance dst pointer
bany a8, a7, .Ldstunalignedloop # if byte 3 is nonzero, iterate
/* Byte 7 is zero. */
.Lu7: RET(16)
.Lu0: /* Byte 0 is zero. */
#if XCHAL_HAVE_BE
movi a8, 0
#endif
s8i a8, a10, 0
RET(16)
.Lu1: /* Byte 1 is zero. */
#if XCHAL_HAVE_BE
extui a8, a8, 16, 16
#endif
s16i a8, a10, 0
RET(16)
.Lu2: /* Byte 2 is zero. */
s16i a8, a10, 0
movi a8, 0
s8i a8, a10, 2
RET(16)
#endif /* 0 */
.end schedule
.size strcpy, . - strcpy