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564c9d7dcd
ARM specifies that SysTick RELOAD must be programmed with N-1 to get a period of N CPU cycles. Adjust the timeout/reload conversions accordingly: subtract 1 when writing RELOAD and add 1 back when converting RELOAD to a timeout/interval. Also clamp RELOAD to the valid 24-bit range (1..0x00ffffff) for Armv7-M/Armv8-M to avoid invalid values. Reference: https://developer.arm.com/documentation/dui0646/c/Cortex-M7-Peripherals/System-timer--SysTick/SysTick-Reload-Value-Register Signed-off-by: Gao Jiawei <gaojiawei@xiaomi.com>
115 lines
3.5 KiB
C
115 lines
3.5 KiB
C
/****************************************************************************
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* include/sys/param.h
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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#ifndef __INCLUDE_SYS_PARAM_H
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#define __INCLUDE_SYS_PARAM_H
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <limits.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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#define MAXHOSTNAMELEN HOST_NAME_MAX
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/* Macros for min/max. */
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#ifndef MIN
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# define MIN(a,b) (((a) < (b)) ? (a) : (b))
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#endif /* MIN */
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#ifndef MAX
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# define MAX(a,b) (((a) > (b)) ? (a) : (b))
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#endif /* MAX */
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#ifndef CLAMP
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/* inclusively clamping a value into a given range */
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# define CLAMP(x, min, max) ((x) <= (min) ? (min) : MIN(x, max))
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#endif /* CLAMP */
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/* Macros for number of items.
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* (aka. ARRAY_SIZE, ArraySize, Size of an Array)
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*/
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#ifndef nitems
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# define nitems(_a) (sizeof(_a) / sizeof(0[(_a)]))
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#endif /* nitems */
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/* Macros for counting and rounding.
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*
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* These macros accept value to be rounded or checked as 'a' and base as 'b'.
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* They are consistent with those provided by some BSDs.
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*
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* howmany() calculates how many b fit into a.
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*
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* rounddown() and roundup() round a to the next b.
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*
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* rounddown2() and roundup2() are for powers of 2 only.
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*
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* powerof2() returns 1 if a is a power of 2, 0 otherwise.
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*
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* Warning: rounddown2() and roundup2() can be used only if b is power of 2,
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* otherwise they will produce wrong result.
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*
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* In all of these macros, outcome is undefined if b is 0.
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*
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* All parameters are assumed to be unsigned integers.
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*/
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#ifndef howmany
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# define howmany(a, b) (((a) + ((b) - 1)) / (b))
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#endif /* howmany */
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#ifndef rounddown
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# define rounddown(a, b) (((a) / (b)) * (b))
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#endif /* rounddown */
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#ifndef rounddown2
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# define rounddown2(a, b) ((a) & ~((b) - 1))
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#endif /* rounddown2 */
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#ifndef roundup
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# define roundup(a, b) ((((a) + ((b) - 1)) / (b)) * (b))
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#endif /* roundup */
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#ifndef roundup2
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# define roundup2(a, b) (((a) + ((b) - 1)) & ~((b) - 1))
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#endif /* roundup2 */
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#ifndef powerof2
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# define powerof2(a) (!(((a) - 1) & (a)))
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#endif /* powerof2 */
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/****************************************************************************
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* Public Type Definitions
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****************************************************************************/
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/****************************************************************************
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* Public Function Prototypes
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****************************************************************************/
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#endif /* __INCLUDE_SYS_PARAM_H */
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