98 lines
3.0 KiB
C
98 lines
3.0 KiB
C
/****************************************************************************
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* net/utils/net_incr32.c
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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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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <nuttx/net/netdev.h>
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#ifndef CONFIG_NET_ARCH_INCR32
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: net_carry32
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*
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* Description:
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* Calculate the Internet checksum over a buffer.
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*
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****************************************************************************/
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static inline void net_carry32(FAR uint8_t *sum, uint16_t op16)
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{
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if (sum[2] < (op16 >> 8))
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{
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++sum[1];
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if (sum[1] == 0)
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{
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++sum[0];
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}
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}
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if (sum[3] < (op16 & 0xff))
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{
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++sum[2];
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if (sum[2] == 0)
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{
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++sum[1];
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if (sum[1] == 0)
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{
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++sum[0];
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}
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}
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}
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}
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: net_incr32
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*
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* Description:
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*
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* Carry out a 32-bit addition.
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*
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* By defining CONFIG_NET_ARCH_INCR32, the architecture can replace
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* net_incr32 with hardware assisted solutions.
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*
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* Input Parameters:
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* op32 - A pointer to a 4-byte array representing a 32-bit integer in
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* network byte order (big endian). This value may not be word
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* aligned. The value pointed to by op32 is modified in place
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*
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* op16 - A 16-bit integer in host byte order.
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*
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****************************************************************************/
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void net_incr32(FAR uint8_t *op32, uint16_t op16)
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{
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op32[3] += (op16 & 0xff);
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op32[2] += (op16 >> 8);
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net_carry32(op32, op16);
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}
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#endif /* CONFIG_NET_ARCH_INCR32 */
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