Architecture specific uIP functions

The functions in the architecture specific module implement the IP check sum and 32-bit additions.

The IP checksum calculation is the most computationally expensive operation in the TCP/IP stack and it therefore pays off to implement this in efficient assembler. The purpose of the uip-arch module is to let the checksum functions to be implemented in architecture specific assembler.

Files
file	uip_arch.h
	Declarations of architecture specific functions.

Functions
void	uip_add32 (uint8_t *op32, uint16_t op16)
	Carry out a 32-bit addition. More...

Variables
uint8_t	uip_acc32 [4]
	4-byte array used for the 32-bit sequence number calculations. More...

void uip_add32	(	uint8_t *	op32,
		uint16_t	op16
	)

Carry out a 32-bit addition.

Because not all architectures for which uIP is intended has native 32-bit arithmetic, uIP uses an external C function for doing the required 32-bit additions in the TCP protocol processing. This function should add the two arguments and place the result in the global variable uip_acc32.

Note

The 32-bit integer pointed to by the op32 parameter and the result in the uip_acc32 variable are in network byte order (big endian).

Parameters

op32	A pointer to a 4-byte array representing a 32-bit integer in network byte order (big endian).
op16	A 16-bit integer in host byte order.

Referenced by uip_process(), and uip_split_output().

uint8_t uip_acc32[4]

4-byte array used for the 32-bit sequence number calculations.

Referenced by uip_split_output().