From b3a177618f8750ae7255b6d660fe15a7a0c62ac7 Mon Sep 17 00:00:00 2001 From: Gregory Nutt Date: Fri, 8 Apr 2016 14:14:28 -0600 Subject: [PATCH] Oops: Forgot to add file in previous commit --- arch/arm/src/armv7-m/iar/up_testset.S | 107 ++++++++++++++++++++++++++ 1 file changed, 107 insertions(+) create mode 100644 arch/arm/src/armv7-m/iar/up_testset.S diff --git a/arch/arm/src/armv7-m/iar/up_testset.S b/arch/arm/src/armv7-m/iar/up_testset.S new file mode 100644 index 0000000000..9590e576e7 --- /dev/null +++ b/arch/arm/src/armv7-m/iar/up_testset.S @@ -0,0 +1,107 @@ +/**************************************************************************** + * arch/arm/src/armv7-m/gnu/up_testset.S + * + * Copyright (C) 2016 Gregory Nutt. All rights reserved. + * Author: Gregory Nutt + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * 3. Neither the name NuttX nor the names of its contributors may be + * used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE + * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, + * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, + * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS + * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED + * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN + * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + * + ****************************************************************************/ + +/**************************************************************************** + * Included Files + ****************************************************************************/ + +#include +#include + + MODULE up_testset + SECTION .text:CODE:NOROOT(2) + +/**************************************************************************** + * Public Symbols + ****************************************************************************/ + + PUBLIC up_testset + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: up_testset + * + * Description: + * Perform and atomic test and set operation on the provided spinlock. + * + * This function must be provided via the architecture-specific logoic. + * + * 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) + * + ****************************************************************************/ + + THUMB + +up_testset: + + mov r1, #SP_LOCKED + + /* Test if the spinlock is locked or not */ + +L1: + ldrexb r2, [r0] /* Test if spinlock is locked or not */ + cmp r2, r1 /* Already locked? */ + beq L2 /* 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 */ + +L2: + mov r0, #SP_LOCKED + bx lr + + END