DBRC trace input

When called, DSPTRACE receives a 16-byte parameter list.

Contents of the parameter list

An 8-character identifier that becomes the first 8 characters of the trace entry.
A 4-byte control block pointer that points to a DFSBRLSB or the DSPRQB.
A 4-byte block area pointer. 64 bytes of data from the block area are inserted in the trace entry. If the pointer is 0, the trace entry is 64 bytes long. Otherwise, the trace entry is 128 bytes long.