114 lines
3.8 KiB
C
114 lines
3.8 KiB
C
/****************************************************************************
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* net/utils/net_incr32.c
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*
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* Copyright (C) 2007-2010, 2012, 2014-2015, 2017 Gregory Nutt. All
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* rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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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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