srec_dec_binary man page

srec_dec_binary — DEC Binary (XXDP) file format


The DEC Binary (XXDP) format was used on the PDP 11 series machines. This is a binary format, and is not readable or editable with a text editor. The file consists of records of the form


The field are defined as follows:

Two byte little‐endian value. Must always be 1.
Two byte little‐endian value. This is the number of bytes in the data, plus six.
Two byte little‐endian value. This is the load address of the data.
The data is simple raw bytes. There are (length‐6) of them.
The checcksum is a single byte. It is the negative of the simple summ of all the header and data bytes.

If the record length is exactly 6 (i.e. no data), this is the execution start address record, indicating the transfer address.

In addition there may be NUL padding characters between records. It is common for records to be padded so that they start on even byte boundaries. In the days of paper tape, it was common for the file to have many leading NULs, to generate blank leader on the tape.

Size Multiplier

In general, raw binary data will expand in sized by approximately 1.03 times when represented with this format.


Scott FinneranE‐Mail:scottfinneran@yahoo.com.au
Peter MillerE‐Mail:pmiller@opensource.org.au

Referenced By

srec_cat(1), srec_input(1).

Explore man page connections for srec_dec_binary(5).