nuttx/arch/arm/src/armv8-m/arm_testset.S
Gregory Nutt 010603329b More compliance to the naming standard.
1) Rename all up_*.S file to arm_*.S
2) Rename all functions used only by armv8_m logic from up_* to arm_*
2020-04-26 14:12:47 -03:00

109 lines
3.7 KiB
ArmAsm
Executable File

/****************************************************************************
* arch/arm/src/armv8-m/gnu/arm_testset.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 <nuttx/config.h>
#include <arch/spinlock.h>
.syntax unified
.thumb
.file "arm_testset.S"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Public Symbols
****************************************************************************/
.globl up_testset
/****************************************************************************
* Assembly Macros
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
.text
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: up_testset
*
* Description:
* Perform an atomic test and set operation on the provided spinlock.
*
* This function must be provided via the architecture-specific logic.
*
* Input Parameters:
* lock - The address of spinlock object.
*
* Returned Value:
* The spinlock is always locked upon return. The value of previous value
* of the spinlock variable is returned, either SP_LOCKED if the spinlock
* as previously locked (meaning that the test-and-set operation failed to
* obtain the lock) or SP_UNLOCKED if the spinlock was previously unlocked
* (meaning that we successfully obtained the lock)
*
****************************************************************************/
.globl up_testset
.type up_testset, %function
up_testset:
mov r1, #SP_LOCKED
/* Test if the spinlock is locked or not */
1:
ldrexb r2, [r0] /* Test if spinlock is locked or not */
cmp r2, r1 /* Already locked? */
beq 2f /* If already locked, return SP_LOCKED */
/* Not locked ... attempt to lock it */
strexb r2, r1, [r0] /* Attempt to set the locked state */
cmp r2, r1 /* r2 will be 1 is strexb failed */
beq 1b /* Failed to lock... try again */
/* Lock acquired -- return SP_UNLOCKED */
dmb /* Required before accessing protected resource */
mov r0, #SP_UNLOCKED
bx lr
/* Lock not acquired -- return SP_LOCKED */
2:
mov r0, #SP_LOCKED
bx lr
.size up_testset, . - up_testset
.end