Arpanet IMP implemented in C

This is part of the effort to add simulated IMP interfaces in SIMH.

See BBN Report 1822 for the protocol used to communicate with the IMP.

API

First reset the IMP:

• t_stat imp_reset (IMP *imp)

Then set imp.receive_bit to a callback which is used to receive data from the network. The callback will receive a boolean bit, and another boolean to say whether the bit was the last in a message. The callback has this type:

• t_stat (*) (int bit, int last)

The IMP accepts data from a host using one of these two APIs:

• t_stat imp_send_bits (IMP *imp, uint64 data, int n, int last)
• t_stat imp_send_packet (IMP *imp, void *octets, int n)

The first function accepts input in the lower n bits of data. Message bits accumulate until last is true.

The second function can be used to send a complete packet with n bits.