1956385a7d
Provide a way to only customize specific string operations, such as for memcpy with the DMA capability by ROM. Signed-off-by: yangdongdong <yangdongdong@xiaomi.com>
129 lines
3.6 KiB
ArmAsm
129 lines
3.6 KiB
ArmAsm
/****************************************************************************
|
|
* libs/libc/machine/xtensa/arch_strlen.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>
|
|
|
|
#include "libc.h"
|
|
|
|
#ifdef LIBC_BUILD_STRLEN
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
.section .text
|
|
.begin schedule
|
|
.align 4
|
|
.literal_position
|
|
.global strlen
|
|
.type strlen, @function
|
|
strlen:
|
|
ENTRY(16)
|
|
/* a2 = s */
|
|
|
|
addi a3, a2, -4 # because we overincrement at the end
|
|
movi a4, MASK0
|
|
movi a5, MASK1
|
|
movi a6, MASK2
|
|
movi a7, MASK3
|
|
bbsi.l a2, 0, .L1mod2
|
|
bbsi.l a2, 1, .L2mod4
|
|
j .Laligned
|
|
|
|
.L1mod2: # address is odd
|
|
l8ui a8, a3, 4 # get byte 0
|
|
addi a3, a3, 1 # advance string pointer
|
|
beqz a8, .Lz3 # if byte 0 is zero
|
|
bbci.l a3, 1, .Laligned # if string pointer is now word-aligned
|
|
|
|
.L2mod4: # address is 2 mod 4
|
|
addi a3, a3, 2 # advance ptr for aligned access
|
|
l32i a8, a3, 0 # get word with first two bytes of string
|
|
bnone a8, a6, .Lz2 # if byte 2 (of word, not string) is zero
|
|
bany a8, a7, .Laligned # if byte 3 (of word, not string) is nonzero
|
|
|
|
/* Byte 3 is zero. */
|
|
addi a3, a3, 3 # point to zero byte
|
|
sub a2, a3, a2 # subtract to get length
|
|
RET(16)
|
|
|
|
/* String 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
|
|
#endif
|
|
.Laligned:
|
|
#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, .Lz3 # loop forever (almost anyway)
|
|
#endif
|
|
1: l32i a8, a3, 4 # get next word of string
|
|
addi a3, a3, 4 # advance string 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
|
|
#if XCHAL_HAVE_LOOPS
|
|
bnone a8, a7, .Lz3 # if byte 3 is zero
|
|
#else
|
|
bany a8, a7, 1b # repeat if byte 3 is non-zero
|
|
#endif
|
|
|
|
.Lz3: /* Byte 3 is zero. */
|
|
addi a3, a3, 3 # point to zero byte
|
|
/* Fall through.... */
|
|
|
|
.Lz0: /* Byte 0 is zero. */
|
|
sub a2, a3, a2 # subtract to get length
|
|
RET(16)
|
|
|
|
.Lz1: /* Byte 1 is zero. */
|
|
addi a3, a3, 1 # point to zero byte
|
|
sub a2, a3, a2 # subtract to get length
|
|
RET(16)
|
|
|
|
.Lz2: /* Byte 2 is zero. */
|
|
addi a3, a3, 2 # point to zero byte
|
|
sub a2, a3, a2 # subtract to get length
|
|
RET(16)
|
|
|
|
.end schedule
|
|
|
|
.size strlen, . - strlen
|
|
|
|
#endif
|