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